A-TYPE : See Jack

AB : See Stereophonic  

AB POWERING : See Phantom Power. 

ABTT : The Association of British Theatre Technicians. 

ACL : Acronym for AirCraft Landing Light. See Aero.

ACOUSTICS :  The behaviour of sound and its study. 
The acoustics of a room depend on its size and shape and the 
amount and position of sound-absorbing and reflecting material. 

ACOUSTIC PICK-UP : See Pick-Up. 

ACT: 1) Subdivision between sections of a play.
A short play is a "One-Act-er", a play with one interval has two Acts etc.
Acts are subdivided further into Scenes. 2)
The thing Actors can do which makes them different from Techies (!!).

ACT DROP : Victorian stretched framed and painted canvas.
Used as a visual stimulation during scene changes, 
and to indicate that there was more to come.
Only operational one today at the Gaiety Theatre, Isle Of Man (unless you know better...).
Term now used to refer to any front cloth or tabs lowered during intervals.
Especially pantomime / musicals.  

ACTING AREA : That area within the performance space within which the actor may 
move in full view of the audience.
(Also name of early Strand down-lighting floodlight - known as "Ack Ack"). 

ACTIVE : A piece of circuitry is termed active if it needs a power supply for 
it to function. (Active DI box, Active crossover etc.)
Circuitry that needs no additional power supply is termed passive 
(eg resistors & capacitors in a crossover). 
Passive circuits use the electrical sound signal itself to operate the components.
OR A piece of circuitry is termed active if it amplifies a signal supplied to it.
A passive circuit does not increase the level of a signal.  

AD LIB : The presence of mind by an actor to improvise when;
1) another actor fails to enter on cue
2) the normal progress of the play is disturbed
3) lines are forgotten
4) It may also be a bad habit developed by some actors  whereby unnecessary 'gags' 
are introduced into the dialogue.

ADAM : See Digital Recording. 

ADAPTOR (or Splitter) : Connector which allows two or more electrical devices to 
be connected to a single power outlet. The connection is normally parallel, that is,
each device is fed the same voltage, but the current is divided between them.
Sometimes known as a "Twofer". A three-way splitter is known as a "Threefer".
A Series splitter is also available where a voltage is shared equally between two loads.  See Series Splitter, Jumper and Grelco. 

ADAT : See Digital Recording. 

ADDITIVE COLOUR MIXING : See Colour Mixing. 

ADVANCE BAR : Lighting bar positioned just downstage of the proscenium arch. 

AERIAL : Cable or rod used to send and receive radio signals 
(connected to transmitter and receiver or tuner). 

AERO :  A type of high intensity Par lamp that derives its name from its use 
as an aircraft landing lamp. The true Aero is 28V and 250W, although there are many variations. The lamp has a very tight beam. 

AETTI : Arts & Entertainment Technical Training Initiative (UK). 

AGC : Automatic Gain Control. Circuitry within recording equipment which 
compensates for differences in volume in the incoming sound signal by adjusting 
the gain automatically. Helps to reduce wild swings in volume. 

AISLE : A passage through seating. 

A.J. : Jargon for an Adjustable Spanner. 

A.L.D. :Association of Lighting Designers.(UK) 

AMP :Abbreviation for ;
 1)  AMPERE, the standard unit for measurement of electrical current passing 
 through a circuit. Cables, fuses and switches are designated by their current 
 carrying capacity. Square pin plugs are rated at 13 Amps maximum and Round pin 
 plugs at either 5 Amps or 15 Amps maximum, depending on the size of the pins. 
 If a cable rated at 5 Amps is used with a load of 15 Amps, the cable will 
 overheat and possibly catch fire.
2) AMPLIFIER -  sound equipment that converts the low voltage, 
low current signal from a tape deck, mixer  etc. into a higher current signal 
suitable for driving speakers. See Power Amplifier, Crossover. 

AMPLITUDE : The strength of a vibrating wave ; in sound, the loudness of the sound. 

ANALOGUE SIGNAL (See Digital) : A continuously variable signal that can have any 
value over a given range. For example, an analogue voltage within the range 
0 to 10 Volts can have values of 0, 2, 8.785 or any value between. 
Most dimmers require an analogue voltage in order to operate 
(from 0 to -10V or 0 to +10V depending on the manufacturer). 
Most lighting control desks produce a digital multiplexed  output, which is 
converted by a demux box to an analogue signal for the dimmer. 
See also Digital dimmer. 

ANIMATION DISC : See Effects. 

A.N.S.I. : American National Standards Institute. 

ANTI-RAKE : The act of modifying furniture or props by shortening the upstage 
legs etc. so that they can stand level on a raked stage. See also Raked Stage.

APRON : Section of the stage floor which projects towards or into the auditorium. 
In proscenium theatres, the part of the stage in front of the house tabs, 
or in front of the proscenium arch. 

ARBOR : US equivalent of CRADLE in a counterweight flying system.

ARC LIGHT : See Discharge lamp. 

ARCHITECTURAL LAMP : A type of linear filament lamp with contacts at 
90 degrees to the filament which can gives the appearance of a continuous 
line of light (similar to neon, but dimmable). 

ARCLINE (Trade Name) : A coloured plastic tube containing a number of small 
strobe units which, when triggered, flash in sequence down the tube. 
Many tubes can be connected together. 

ARENA : Form of stage where the audience are seated on at least two 
(normally three, or all four) sides of the whole 
acting area. See Thrust. 

ASIDE : Lines spoken by an actor to the audience and not supposed to be 
overheard by other characters on-stage.

ASM :  Assistant Stage Manager. 

ATTENUATE : To reduce the intensity of a sound signal. 

ATMOSPHERE : The normal background sound at any location. 

AUDITORIUM : The part of the theatre accommodating the audience during the 
performance. Sometimes known as the "house". 

AUTOMATIC STOP : Many reel-to-reel tape players for theatrical use have a 
facility that stops the tape mechanism when a piece of clear leader passes 
a detector adjacent to the erase head. This can be used to cue the tape up 
ready to start the next effect. 

AUTOMATION : 
1) Facility available on larger sound mixing desks allowing channel muting 
or even fader 
moves to be taken under the control of a computer to ensure accurate and 
repeatable mixing. 
2) Describes the method used instead of stage crew for moving bits of set 
around shows with 
a big budget.

AUXILIARY OUTPUT or SEND : An additional output from a sound desk which 
can be used for foldback or monitoring without tying up the main outputs. 
Each input channel will have a path to the Aux buss. Also used for feeding 
a signal to an effects processor. See Auxiliary Return. 

AUXILIARY INPUT or RETURN : A route back into the sound desk for a signal 
sent to a piece of outboard equipment via an auxiliary send. 


B    Back To Top


B-TYPE : See Jack. 

BACK CLOTH : See Cloth. 

BACKFLAP : Hinge frequently used in Scenic Construction. 

BACKING :
 1) Scenic piece as a backing behind an opening in the set (window etc.) 
 which hides the technical areas beyond.
 2) The money invested in a commercial production (by a Backer). 

BACKLIGHT : Light coming from upstage, behind scenery or actors, to sculpt 
and separate them from the background 

BACK PROJECTION : See Projection. 

BACKSTAGE : The part of the stage and theatre which is out of the sight of 
the audience. The service areas of the theatre. 

BACK-UP : A section of a lighting control board (sometimes a separate unit) 
which provides an alternative method of control should the main board fail. 

BAFFLE : 
1) A sheet of material used to prevent a spill of light in a lantern or 
in part of a set.
2) A panel in a loudspeaker cabinet designed to reduce back interference 
noise by isolating the front and rear of the loudspeaker diaphragm.
3) A panel in an auditorium positioned so as to reduce sound reflections 
and improve the acoustics of the space.4) What most of this jargon will 
do to any non-technical theatrical type.

BAKELITE :(Trade Name) Early type of thermosetting plastic often used for 
electrical plugs and sockets.  Has a distinctive fishy (ammonia) smell when burning. 

BALANCED LINE : A method of carrying sound signals which reduces interference 
by using a third conductor, the shield. The two inner conductors carry the 
same sound signal, one is positive and the other is negative. 
Any interference induced into the cable is equal and opposite in each 
of the inner conductors and is cancelled out. 
It is important to use balanced lines when carrying low level signals 
(e.g. microphones) along long cable runs. See unbalanced line. 

BALCONY RAIL : See Circle Fronts.

BALLAST : A unit used in conjunction with discharge lamps containing 
capacitors, inductors and other start-up circuitry. 
The inductor is initially used to develop a high potential to strike the 
discharge and is then used to limit the current flow while the lamp is lit. 

BALLYHOO : Swinging a followspot beam around in a figure of eight pattern.

BANTAM : See Jack. 

BAR : 
	The horizontal metal tube (usually 48mm in external diameter) hung 
	from flying lines (or forming part of a grid) from which lighting 
	equipment and scenery etc. may be suspended. Also known as a Barrel. 
	When vertical, known as a Boom. Sometimes known as a Pipe in the US, 
	although many curse that usage, and demand the use of Batten ; 
	"A pipe is what you smoke; a batten is what you hang your instruments from." 

BAR BELLS : 
are rung in public areas of the theatre to warn the audience that the 
performance is about to start/continue. Usuallyoperated from the prompt corner 
and sometimes followed by Front of House Calls. The bells are also used as a 
warning to FOH staff that the interval is about to commence or that the show 
is about to end. 

BARNDOORS : A rotatable attachment consisting of two ir four metal flaps 
which is fixed to the front of a Fresnel or PC type lanternto reduce the 
beam spread in one or more directions. 

BASE PLATE : A metal plate which prevents damage to floors when using scaffolding
 or trussing. 

BASS : Lower end of the musical scale. In acoustics, the range (below about 200Hz) 
in which there are difficulties, principally in the reproduction of sound, due to 
the large wavelengths involved. 

BASS BIN : : Speaker cabinet containing Woofer designed for Bass sound reproduction
(see also Subwoofer). 

BASTARD SIDE (B.S.) : 
Terminology used when the Prompt corner is Stage Right. Stage Left is then 
known as Opposite Bastard (O.B.)  

BATTENS :
1) Timber at the top and bottom of a cloth. A Sandwich batten is used to 
carry a hanging cloth. It comprises two flat pieces of timber screwed
 together with the edge of the cloth between them.  
2) Timber used for joining flats together for flying. 
3) Compartmentalised floodlights set up so as to allow colour mixing.
 See also groundrow. Low voltage battens are commonly used as light 
 curtains & for colour washes. 
4) US term interchangable with PIPE for a flying bar. 

BC HOLDER : Type of domestic lampholder that has largely been replaced 
by the ES (Edison Screw) and the GES (Goliath Edison Screw) for general 
lighting applications in the theatre. Stage lighting equipment 
uses prefocus lamp bases. (Most types of Festoon still use BC holders.) 

BEAM ANGLE : The angle of the cone of light produced by a lantern. 
Defined as the angle within which the lowest intensity in a beam of 
light from a lantern is not less than one-tenth of the maximum. 

BEAMLIGHT : Flood lantern which uses a parabolic reflector and a low 
voltage high intensity lamp to produce an intense near-parallel beam. 
Also known as a Beam Projector. 

BECTU : Broadcasting, Entertainment, Cinematograph and Theatre Union. 
The UK entertainment technicians union. 

BEGINNERS : A call given by the DSM to bring those actors who appear 
in the first part of a play to the stage. e.g. "Act One Beginners to 
the stage, please". The actors/actresses are then called by name. 

BELL BOARD : A live sound effects board on which are mounted a number 
of different types of doorbells /  phone bells etc. Usually operated 
by stage management. 

BI-AMPLIFICATION : A way of optimising the efficiency of a speaker 
system by separately amplifying the High Frequency (HF) and Low Frequency (LF) 
portions of the sound signal and sending them down two pairs of cables 
to the speaker. Multipin Speakon connectors have been developed to do this. 

BIFOCAL SPOT : Profile lantern with two sets of shutters, one of which 
produces a hard edge, and one a soft edge. Not necessary in zoom 
profiles, because this requirement is fulfilled by two lenses. 

BILLY BLOCK : A pulley on a short length of rope used to divert the pull
 of a working rope, or to suspend a single item in storage. 

BIOBOX: (Aus) See DOME.

BIRDIE : A compact display luminaire containing a Par 16 lamp. So called 
because it is similar to, but much smaller than, the Parcan, and is 
hence "one under Par". 

BLACK HOLE : Accidentally unlit portion of the stage. 

BLACK LIGHT : See Ultra-Violet. 

BLACKS  : 
1) Black clothing worn by stage management during productions. 
2) Any black drapes or tabs, permanently or temporarily rigged. 
Used for masking technical areas. 

BLACKOUT : Complete absence of stage lighting. Blue working lights 
backstage should remain on and are not usually under the control of 
the board, except during a Dead Blackout (DBO), when there is no onstage light. 
Exit signs and other emergency lighting must remain on at all times. 

BLEECON : Trade name for a type of low voltage 8 pin connector which is 
similar to the audio DIN plug. Used most often for carrying signals from 
analogue lighting control desks to dimmers or to demux boxes. Originally 
manufactured by Belling and Lee. 

BLEED : Dimmers which are incorrectly trimmed are said to bleed. 
That is, the dimmer still gives a small output, causing the lantern 
to glow, when the control signal is at a minimum. 

BLEED THROUGH : Transformation from a scene downstage of a gauze to another 
scene upstage, by slowly crossfading lighting from downstage to upstage. 
If a gauze is lit steeply, or from the sides, it will appear solid. 
If this light is turned off and light added to the set upstage of 
it, it will disappear. 

BLINDERS : Lamps arranged around the stage directed into the 
auditorium , originally to prevent spectators seeing the stage during 
scene changes when the house tabs were not lowered. 
Now used for effect in rock concerts etc. 

BLIND PLOTTING : The facility on some lighting control desks for the 
operator to make changes to the plot, without affecting the state on stage. 

BLOCK : Frame in which one or more pulley wheels (sheaves) are mounted. 

BLOCKING : The process of arranging moves to be made by the actors during 
the play, recorded by stage management in the prompt script. 

BLUES : Blue lights used backstage in a performance situation. 
See also working lights. 

BNC:  (Bayonet Neill Consulman - after original inventors) 
Coaxial connector used for carrying a composite video signal or radio 
frequency signal. 

BOARD : The main control for the stage lighting. 
Originally known as the switchboard or dimmerboard, it is now 
usually remote from the dimmers. The lighting operator for a show 
is said to be "on the board". 

BOMB TANK : Metal bin or box covered with fine mesh in which Theatrical 
Maroons can be safely detonated. 

BOOK :  See Prompt Book.  

BOOK FLAT : Two-fold piece of scenery. Book flats are free-standing when 
angled open, allowing quick setting and compact storage. Booking describes 
the action of opening or closing a book flat.  

BOOM :
1) Vertical scaffolding pole (usually 48mm diameter) on which horizontal
 boom arms can be mounted, carrying lanterns. Often used behind wings for 
 side-lighting etc. Booms have a base plate or stand at the bottom and are 
 tied off to the grid or fly floor at the top (not always necessary
  for short booms). Booms can also be fixed to the rear of the 
  procenium arch (Pros. Boom) or hanging from the ends of lighting bars. 
  Sometimes known in the US as a light tree. A light tree mounted upstage 
  of a Tormentor is known as a Torm Tree. 
2) An arm mounted on a microphone stand. 

BOOM ARM : See Boom. 

BORDER : A narrow horizontal masking piece (flattage or cloth), normally of 
neutral colour to mask the lighting rig and flown scenery from the audience, 
and to provide an upper limit to the scene. Often used in conjunction with legs. 

BOSS PLATE : Metal plate fixed to the stage floor into which a bolt can be 
screwed for fixing scenery. 

BO'SUN'S CHAIR : A small seat or cradle rigged on a rope over a pulley 
whereby a technician may be hoisted to work at an otherwise inaccessible position. 

BOTTLESCREW : (Also Bottle Strainer) Threaded device which is used to 
tension a wire, or to provide an adjustable link in a cable, to fine-tune 
the height of flown scenery. (Known in the USA as a Turnbuckle) 

BOUNCE : 
1) Diffuse light that has been reflected from the stage, walls, cyc etc. 
2) Describes the fast in/out movement of "bouncing" flown house tabs, used 
during curtain calls. This can also apply to the fast blackout/lights up 
cues that happen at curtain calls. 
3) This facility is available on many multitrack tape machines. Describes 
the mixing down of multiple sounds from different tracks onto one track,
 hence freeing up the other tracks to be re-used. Allows many sounds to 
 be recorded onto one tape. 

BOUNDARY MIC. : A microphone mounted on a flat plate which acts as a 
reflective surface directing sound into the mic capsule. Used for general 
pick-up over a large area. See PCC, PZM. 

BOX BOOM : US term for a front of house vertical lighting position 
(predominantly sidelight).

BOX SET : Naturalistic setting of a complete room built from flats 
with only the side nearest the audience (the fourth wall) missing. 

BRACE :
1) Angled strengthening timber within a flat. 
2) Support for scenery (flattage) on stage
a. Extendible, hooking into a screw eye on the flat and being weighted 
to the floor (commonly known as a "Stage Brace")
b. French, right-angled non adjustable triangular frame, made from timber, 
and attached to the flat with pin hinges. Often swung flush to the flat 
for storage or flying.
See also Jack (US for Brace). 

BRACE WEIGHT : Slotted cast iron weight placed on foot of extendible or 
French brace to prevent movement. Often referred to as a "Stage Weight" 

BRAIL : A rope, wire or chain attached at either end of a piece of scenery 
or lighting bar pulling it upstage or downstage of its naturally hanging 
position to allow another flying item to pass, or to improve its position. 
See also Breast Line. 

BREAK A LEG :A superstitious and widely accepted alternative to "Good Luck" 
(which is considered bad luck). 
A more full derivation of the term can be found here. 

BREAKAWAY : Prop or item of furniture designed to break/shatter with impact. 
Breakaway furniture and some props are usuallycapable of restoration to
be "broken" again. 

BREAST LINE : A form or brail horizontally across the width of the stage, 
passed across the fly bars suspension lines and attached at the fly floors 
to brail the scenery up or down stage. 

BRIDGE  : A walkway, giving access to technical and service areas above the 
stage or auditorium, or linking fly-floors. 

BRIDGE LIFT : An elevator which raises and lowers sections of the stage floor, 
usually by electrical or hydraulic means. 

BRIDLE : Two or more wires, ropes or chains attached by a ring, eye or shackle 
to the end of a grid line and fitted at distances apart with clips to a 
barrel or batten and thus distributing the load. 

BSI : British Standards Institute. 

BUBBLE : (especially TV and Film) Replacement lamp. 

BUILD : 
1) During lighting plotting, to construct a state from blackout, or to add to 
an existing state. 
2) An increase in light or sound level. See Check. 
3) A period of set construction ("The Build") 

BUMP : A flash or sudden jump in light level (a snap cue) (see Flash Button). 

BURNT OUT : A coloured gel that has lost its colour or melted through due to 
excessive heat in front of a lantern. Dark blues and greens etc. are most 
susceptible, and may need replacing during a long run. 

BUSBAR : Metal bar carrying incoming electrical supply into which portable 
dimmer racks or other large power requirements can be wired directly. 
An enclosure containing busbars is a Busbar Chamber.

BUSS : A signal line within a sound mixing desk that can receive its signal 
from a number of sources. eg the Aux 1 buss carries the signals from the 
input channels to the Aux 1 Send master control. 


C    Back To Top

C-WRENCH : US for SPANNER. (Abbreviation of Crescent Wrench, named for the curved shape of the tool).

CABLE : Wiring, temporarily rigged, to carry electrical current. Depending on the size of the cable (current carrying capacity), cables are used to supply individual lanterns, whole dimmer racks, or carry signals from a microphone etc. 

CABLE GRIP : A U-shaped clip and saddle used for terminating wire rope. Also known as a Bulldog, Dog Grip or Wire Rope Clip. 

CABLE TIE : Lockable (and sometimes releasable) plastic strap used to tie a bundle of cables together, amongst many other things. 

CAD : Computer-Aided Design. Using a computer to help with 2D plans and drawings, or increasingly for 3D visualisation of how a set will look, and how lighting will affect it. 

CALL :
1) A notification of a working session (eg a Rehearsal Call) 
2) The period of time to which the above call refers. (eg "Your call for tomorrow nights show is 6.55pm") 
3) A request for an actor to come to the stage because an entrance is imminent (these are courtesy calls and should not be relied on by actors - eg "This is your call for the finale Mr Smith and Miss Jones") 
4) An acknowledgement of applause (eg Curtain Call) 
5) The DSM on the book is said to be "calling the cues". 

CAMLOCK :(Trade Name) Single pole connector used on professional power distribution & 
dimming systems. A separate connector is used for each phase/neutral of the supply. 
Originally developed for touring concerts, as power demands increase it's finding more use in
theatres. 


CANS : Headset earpiece and microphone used for communication and 
co-ordination of technical departments during a performance. Also generally used for headphones. 

CANVAS : Used to cover flats as a less heavy alternative to plywood. 

CARDIOD : See Pick-up. 

CAROUSEL : Circular slide magazine; also refers to a 35mm slide projector using this type of magazine (Kodak trade name). See Projection. 

CARPET CUT : A narrow concealed slot along the front of the proscenium stage for clamping the downstage edge of a floorcloth. Becoming obsolete. 

CARTRIDGE : A tape loop in a box which can cue itself up to the beginning of the recorded track in a cartridge player. Used extensively for radio jingles, and sometimes for theatre sound effects. 

CASSETTE : Originally, Compact Cassette. Popular domestic 1/8" tape format. Difficult to cue up accurately, so awkward for live theatre, but cheap, so often used by small scale touring companies as sound effects source. A different cassette is used for each effect. Still popular in four track music applications. 

CASTING : The process of the director choosing actors to perform the characters in the play. 

CASUALS : Part-time temporary technicians (paid by the hour). 

CATWALK : An access walkway to equipment. Unlike a Bridge, not necessarily across a void. 

C.C.T.V. : Closed Circuit television. A video relay system, used in the theatre to give a view of the stage to remote technical operators (especially stage managers). Also used to give musical performers a view of the conductor (and vice versa) to help in keeping time. 

C CLAMP : US equivalent of the Hook Clamp. Requires a spanner/wrench to tighten. 

CD (Compact Disc) : Digital sound storage medium. Provides a high quality source of music, sound effects etc. Also used as a playback medium for sound effects etc by large theatres with long running shows, although CDR (Recordable CD) is becoming more affordable by the day. 

CENTRE LINE : Imaginary line running down the stage through the exact centre of the proscenium opening. Marked as CL on stage plans. Normally marked on the stage floor and used as a reference when marking out or assembling a set. 

CHANNEL : A complete control path for signals in lighting or sound equipment. 

CHASE : A repeated sequence of changing lighting states. 

CHEAT SHEET : A smaller version of the lighting plan, used by the lighting designer during the lighting plot. 

CHECK :
1) Opposite of Build; a smooth diminishment of light or sound level. 
2) See Prefade Listen. 

CHIEF ELECTRICIAN : The senior member of the theatre's stage lighting team, although not necessarily the lighting designer. 

CHINAGRAPH PENCIL : Usually white, wax-based pencil used for marking magnetic tape prior to splicing. Also used for marking identifying numbers of lighting gels. 

CID (Compact Iodide Daylight) : A high intensity discharge lamp that produces a light similar in colour temperature to daylight approx. 5500K). A 1000W CID lamp produces 2.5 times more light than a 2000W tungsten halogen source. 

CIE (Commission Internationale d'Eclairage) : International lighting forum which has produced a series of universally recognised symbols for lighting plans. 

CIRCLE : The balcony with tiered seating above the stalls. Also known as Dress Circle or Grand Circle. 

CIRCLE FRONTS : A permanent front of house lighting position in older proscenium theatres. A number of spotlights, sometimes fitted with colour changers, are recessed into the front of the circle balcony above the stalls. Sometimes known as the Balcony Rail position. 

CIRCUIT : 
1) The means by which a lantern is connected to a dimmer or patch panel. Numbered for reference. 
2) A complete electrical "loop" around which current can flow. 

CITT : Canadian Institute for Theatre Technology. 

CIRCUIT BREAKER : An electro-mechanical "fuse" that can be reset, rather than having to be replaced. Available in the same ratings as fuses. See MCB, RCD. 

CLEANERS : Auditorium working lights. Used for cleaning and setting up the auditorium before the house lights (usually more atmospheric) are switched on. 

CLEARANCE : Message passed to Stage Management from the Front of House Manager that the house is ready for the performance to begin. (ie everyone is in their correct seat and there are no coach parties coming through the doors). 

CLEARING STICK : A long, often bamboo, rod used to rescue flying objects or to prevent them from becoming entangled. 

CLEAT : Piece of timber or metal for tying off a rope line. Used when flying or for holding scenic pieces together with a cleat line. 

CLEAT LINE : Rope passed through cleats on two adjacent flats alternately to hold the flats together. 

CLEW : A ring of metal which is used to join several flying lines or wires to a single pulling wire. 

CLICKTRACK : Technique for reinforcing the live sound of a musical or band with recorded sound from one track of a tape. The other track of the tape consists of a click used by the musical director to keep the live band and cast synchronised with the recorded band or cast. 

CLIPPING : Distortion in a sound signal caused by an amplifier or mixer being unable to handle the level of signal being fed to it. 

CLOTH : A piece of scenic canvas, painted or plain, that is flown or fixed to hang in a vertical position. A Backcloth hangs at the rear of a scene. A Floorcloth is a painted canvas sheet placed on the stage floor to mark out the acting area, or to achieve a particular effect. A Frontcloth hangs well downstage, often to hide a scene change taking place behind. Cut cloths have cut-away open areas and are normally used as a series, painted in perspective. A Star Cloth (usually black) has a large number of small low-voltage lamps sewn or pinned through it which gives a magical starry sky effect. (See also Fibre Optics). In the US, a cloth is known as a Drop (from backdrop). 

CLOVE HITCH : Invaluable knot that every technician should know. 

COLOUR : See Colour Filter. 

COLOUR CALL : A list compiled from the lighting plan of all the colours needed for the rig, and their size. This term also applies to the act of preparing colour filters and frames from such a listing. 

COLOUR CHANGER :
 1) Scroller, where a long string of up to 16 colours is passed horizontally in front of a lantern. Remotely controlled by the lighting desk. 
2) Wheel : Electrically or manually operated disc which is fitted to the front of a lantern with several apertures holding different colour filters which can be selected to enable colour changes. Can also be selected to run continuously. 
3) Semaphore, where framed colours are electrically lowered into place in front of the lantern. Remotely controllable. Can perform additive colour mixing by lowering two colours into position at the same time. 
4) Magazine : Manual semaphore-type device used on the front of a followspot. 

COLOUR CORRECTION : The use of colour filters to compensate for the different colour temperatures of different light sources. Important in lighting for TV and film. 

COLOUR FILTER : A sheet of plastic usually composed of a coloured resin sandwiched between two clear pieces. The coloured filter absorbs all the colours of light except the colour of the filter itself, which it allows through. For this reason, denser colours get very hot, and can burn out very quickly. 

COLOUR FRAME or Gel Frame : A frame which holds the colour filter in the guides at the front of a lantern. Many different sizes of frames are needed for the different lanterns. 

COLOUR MIXING : Combining the effects of two or more lighting gels ;
1) Additive : Focusing two differently coloured beams of light onto the same area (eg Cyc Floods). Combining colours in this way adds the colours together, eventually arriving at white. The three primary colours additively mix to form white, as do the complementary colours. 
2) Subtractive : Placing two different gels in front of the same lantern. Subtractive mixing is used to obtain a colour effect that is not available from stock or from manufacturers. Because the ranges of colour are so wide, the need for subtractive mixing is reducing. Combining colours in this way reduces the light towards blackness. The three primary colours mix subtractively to form black (or to block all the light). 

COLOUR TEMPERATURE : 
A measure of the warmth or coolness of light sources and colours. Measured in degrees Kelvin. The human brain automatically compensates for different colour temperatures - a film or video camera cannot, and thus what we see as white may appear to have a blue or green tint when no colour correction is used for video. Daylight is approximately 5600K and Tungsten Halogen is approx. 3200K. 

COMPANDER : Outboard sound equipment. Combination of a Compressor and an Expander. 

COMPANY : The cast, crew and other staff associated with a show. 

COMPLEMENTARY COLOURS : Pairs of colours which, when additively mixed, combine to produce white light. Examples are red + cyan, green + magenta, and yellow + blue. 

COMPOSITE GOBO : See Gobo. 

COMPRESSOR : A piece of sound processing equipment that ensures all wanted signals are suitably placed between the noise and distortion levels of the recording medium. It evens out the unwanted changes in volume you get with close-miking, and in doing so, adds punch to the sound mix. A Limiter is used to stop a signal from exceeding a preset limit. Beyond this limit, the signal level will not increase, no matter how loud the input becomes. A Limiter is often used to protect speaker systems (and human ears) by preventing a system from becoming too loud. 

CONDENSER LENS : Loosely applied to any spotlight lens which condenses diverging rays into a beam, but more correctly to the short focus combination of two or more lenses in a jacket used for illuminating a slide or effect disc. Also used in some profile lanterns and followspots to produce a smoother light (especially for gobo work). 

CONDENSER MIC (Capacitor Mic) : A microphone that uses the varying capacitance between two plates with a voltage applied across them to convert sound to electrical pulses. Condenser microphones need a power supply to provide the voltage across the plates, which may be provided by a battery within the case of the microphone, or it may be provided from an external phantom power supply. A condenser mic is more sensitive and has a faster reaction to percussive sounds than a Dynamic mic and produces a more even response. See Electret Mic. 

CONDUIT : Metal or plastic pipe used to carry electrical conductors as part of a permanent electrical installation. Also used to add weight to the bottom of a flown cloth. 

CONTACT MIC : A microphone that directly picks up the sound transmitted by a solid material. See Boundary Mic, PCC, PZM. 

COOKIE : See Gobo. 

CORNER PLATE : A triangle of plywood used to strengthen the corners of a flat. 

COUNTERWEIGHT : A standard weight (60 or 30 lb.) used in a counterweight flying system. 

COUNTERWEIGHT SYSTEM :  Method of flying scenery which uses a cradle containing weights to counterbalance the weight of flown scenery. See Double Purchase, Single Purchase, Flying.  

COVE : US for front of house catwalk lighting positions. Also "Balcony Rail".

CRACKED OIL : A smoke effect which creates a haze in the air to make light beams visible. This effect is rarely used now, because it has been found to be carcinogenic. See Water Cracker. 

CRADLE : Metal frame in which counterweights are carried in a flying system. 

CROSBYS : US for saddle and "U" cable clamps (from the manufacturers name).

CROSS FADE : Bringing another lighting state up to completely replace the current lighting state. Also applies to sound effects / music. Sometimes  abbreviated to Xfade or XF.  

CROSSOVER : 
1) A route leading from one side of the stage to the other, out of the audiences view. 
2) An electronic filter in a sound system that routes sound of  the correct frequency to the correct part of the speaker system. Different speakers handle high frequencies (tweeters) and low frequencies (woofers). Sometimes known as a crossover network.
An active crossover splits the signal from the mixing desk into high, mid and low frequencies which are then sent to three separate amplifiers. 

CSI (Compact Source Iodide) : A high intensity discharge  lamp. Most often used in followspots, because it has a colour temperature  (approx. 4000K) close to that of the tungsten halogen lamps. 

CSM : Company Stage Manager 

CUE : The command given to technical departments to carry out a particular operation. E.g. Fly Cue or Sound Cue. Normally given by stage management, but may be taken directly from the action (i.e. a Visual Cue).  

CUEING : There is a standard sequence for giving verbal cues :
"Stand-by Sound Cue 19"	(Stand-by first)
"Sound Cue 19 Go"	(Go last).  

CUE LIGHT  : System for giving technical staff silent cues by light. Red light means stand-by or warn, green light means go. 
Ensures greater precision when visibility or audibility of actors is limited. Sometimes used for cueing actors onto the set. 
For technical cues, lights are normally now used just as a backup to cues given over the headset system. 

CUE TO CUE ("Topping and Tailing") : Cutting out action and dialogue between cues during a technical rehearsal, to save time. 

CUT CLOTH :See Cloth. 

CUT-OUT :    See Profile 

CYC FLOOD : A floodlight, usually with an asymmetrical reflector, designed to light a cyc or backcloth from the top or bottom. In the US, a flood at the top of the cyc is a CYC OVER, and a flood at the bottom is a CYC UNDER. 

CYCLORAMA (usually just "cyc") : Plain cloth or plastered wall filling the rear of the stage. The term is often loosely applied to a blue skycloth, or any flattage at the rear of the stage. Maybe curved at the ends. A more effective backing can be obtained by hanging a sharkstooth gauze just in front of the plain white cyc which gives a hazy effect of distance. 


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D54 : See Multiplex. 

DAISY-CHAINING : Connecting items of equipment together by linking from one to the next in a chain. Used for connecting demux boxes to dimmers etc. 

DAT (Digital Audio Tape) : See Digital Recording. 

DARK  : A venue that has been closed to the public. Some theatres go dark temporarily during production periods, when the next show is in preparation on stage.  

DAYMAN : A member of the backstage staff whose employment includes work done in day-time. 

DBO (Dead Blackout) : See Blackout. 

DBX : A noise reduction process. 

DCC (Digital Compact Cassette) : See Digital Recording.  	

DEAD :
1) A pre-plotted height for a piece of scenery or lighting bar - "that bar's on its dead". Sometimes flying pieces are given a number of extra deads, that may be colour coded, in addition to the "in dead" (lower) and "out dead" (higher - out of view). In the US, Trim has the same meaning. 
2) Scenery or equipment not needed for current production - "that table's dead". 
3) An electric circuit that has been switched off or has failed. 

DEAD HANG : To fly an item without a counterweight.

DEAD HINGE : A hinge used as a right-angle bracket. 

DEAD ROOM : A room with very thick sound absorbers, causing a very dull sound with no reverberation. 

DECIBEL (dB) : Relative measurement for the volume (loudness) of sound. Also used to measure the difference between two voltages, or two currents. See Zero dB. 

DECK : 
1)  Stage/Rostrum Floor 
2) Tape deck/Record deck. 

DELAY : Outboard sound equipment that can momentarily stores a signal being sent to part of a P.A. system so that delayed reinforced sound reaches the audience at the same time as live sound from the stage.  
 
DEMUX BOX : Interface unit between the serial digital output of a memory lighting control desk to the parallel analogue signal understood by a dimmer. 

DE-RIG : The process of removing lanterns & cabling from flying bars or grid - returning the venue to it's normal state, or as preparation for the next production. 

DESIGNERS CONTROL : See Riggers Control. 

DI BOX : Interface unit to convert the high impedance unbalanced output of an instrument (e.g. Electric guitar) into a low impedance balanced signal of low level suitable for connection to the microphone input of a mixing desk. 
Usually has an output jack socket so that the instruments unprocessed signal can be passed direct to the musicians amplifier. DI = Direct Injection. 

DIAPHRAGM :  
1) See iris. 
2) The part of a microphone which responds to sound waves. 

DICHROIC FILTER : Glass colour filters which reflect all light except that which is the colour of the filter, which passes through. Normal gels absorb the unwanted colours, turning the light into heat. Dichroic filters run cooler, and produce a much cooler beam of light. Longer lasting, but a lot more expensive. 

DICHROIC LAMP : A low voltage display lamp with a reflector that lets heat pass through it, rather than reflecting it. Results in a much "cooler" light.  
 
DIFFUSION : See Frost. 

DIGITAL : Many electronic devices use digital logic. Information is handled in separate bits (either ON or OFF) rather than continuously variable analogue signals. Most computer lighting boards give a digital multiplexed output, and more and more sound equipment is going digital. 

DIGITAL DIMMER : The new generation of dimmers that can respond directly to the digital multiplexed output of the lighting desk. The technology also permits the dimmer to report faults and other data back to the control board. 

DIGITAL EFFECTS : Reverb, Delay, Phasing, Flanging, Harmonising, Chorusing. More information coming soon ! 

DIGITAL RECORDING :
1) ADAM : (Akai Digital Audio Multitrack). 12 track recording onto Video 8 tape. 16 bit, 44.1 or 48kHz sampling rate.  
2) DAT (Digital Audio Tape) Cassette-like system which has much higher quality than standard audio cassettes. Widely used in gathering sound effects, for news gathering, and for playback of music. 
3) DCC (Digital Compact Cassette) Rival to DAT which also plays standard audio cassettes. 
4) Mini Disk : Uses computer disk technology, rather than tape. A laser heats an area of magnetic disk which is then written to by a magnetic head. When cooled, the magnetic information is read from the disk by laser. Tracks can be named, and are instant start. Very theatre-friendly system. 
5) Direct to Disk : Uses the hard disk present in most PCs as the recording medium. 

DIMMER : Electrical or electronic device which controls the amount of electricity passed to a lantern, and therefore the intensity of  the lamp. 

DIMMER RACK : A number of individual dimmer circuits mounted in a cabinet. 

DIN : Deutscher Industrie Normen. European standard covering audio connectors and tape equalisation characteristics. 

DIP :
1) Small covered trap at stage level containing electrical outlets. 
2) Lighting equipment on stands at stage level. 
3) Low lighting intensity when cross fading between two higher states. 
4) Transparent lacquer for colouring lamp bulbs. 

DIPOLE :

DISCHARGE LAMP : A high-powered source of light produced by means of a discharge between two electrodes. An arc light, for example uses a discharge between two carbon rods which are manually or automatically fed together as they are burnt up. The use of this type of lighting is restricted to non-dimming applications such as followspots and projection, where dimming is achieved by mechanical means.  Many of the new generation of moving lights use discharge lamps and dichroic filters. See Ballast, CSI, CID, MSR, HMI, HTI, Xenon, MBI. 

DISSOLVE UNIT :  Interface connected between two or more slide projectors and a tape player. Synchronisation signals recorded onto the tape are detected by the dissolve unit and fade up the lamp in one slide projector while changing the slide in the other, and then vice versa, producing a dipless crossfade between the two images. 

DISTORTION : Usually undesirable result of overloading sound equipment. Reducing the levels can remedy the situation. 
 
DISTRIBUTION BOARD : System of interconnected fuse carriers and cabling that routes an incoming power supply to a number of different outputs. 

DIVERSITY : A way of maximising the quality of received radio signal by using two receivers and aerials tuned to the same frequency - the circuitry automatically silently switches to the strongest signal. 

DMX512 : See Multiplex. 

DOCK : See Scene Dock. 

DOLBY : Trade name for a series of noise reduction systems that have become standard on many tape playback machines. Many film soundtracks are produced using this process. Different varieties are found from Dolby B on most personal cassette players, to Dolby SR and Digital, the current state of the art for cinema.  

DOLLY : A small wheeled platform used to move heavy items. (E.g. a piano dolly). 

DOME: (Aus) Follow spot location usually at rear of the upper gallery. Also refered to as BIOBOX (shortened version of BIOGRAPH BOX).

DONUT : A metal plate with a hole in the middle inserted in the colour runners of a lantern to sharpen focus (in the case of a profile) or reduce spill. 

DOOR SLAM :  A small wooden box with a heavy door and various bolts and locks used to simulate slamming and other door sound effects offstage. 

DOUBLE HANDLING : Moving scenery and other equipment more than necessary because it wasn't properly sorted or positioned in the first place.

DOUBLE PURCHASE  : Counterweighted flying system where the cradle travels half the distance of the fly bar, leaving the side wall of the stage under the fly floors clear of flying equipment. The cradle of a double purchase system needs twice as many counterweights as that of a single purchase system balancing the same weight.  

DOWNLIGHT :  A light from directly above the acting area. 

DOWNSTAGE : 
1) The part of the stage nearest to the audience (the lowest part of a raked stage). [Diagram] 
2) A movement towards the audience (in a proscenium theatre). 

DOWSER : A metal flag used in larger followspots and projection equipment to cut off the light beam without cutting off the electrical supply. Discharge lamps need a period of cooling down when they are turned off before they can be turned on again, so they should not be switched off if needed again within about two hours. 

DRAPES : Stage Curtains. See also tabs. 

DRENCHER : System of pipes arranged at the top of a safety curtain to drench it with water in the event of fire. 

DRESS CIRCLE : See Circle. 

DRESSER : Helps actors with costume care and costume changes during the performance. 

DRESSING (the set) : Decorative props (some practical) and furnishings added to a stage setting. See also Tab Dressing. 

DRESS PARADE : Review by director/designer/wardrobe staff of all costumes worn by cast and paraded under stage lighting. Any defects, misfits etc. are noted or corrected before the first Dress Rehearsal. 

DRESS REHEARSAL : A full rehearsal, with all technical elements brought together. The performance as it will be "on the night". 

DRIFT : The effective travelling distance of a suspension barrel between the stage and the underside of the grid.  The drift will be variable depending on the depth of a scenic piece suspended beneath the barrel.  ie the comment "there isn't enough drift" will usually mean that a piece cannot be flown out sufficently high to mask.

DRIFT WIRE : A length of suspension wire of standard length with eyelets at each end between the counterweight bar and the top of the scenic piece flown from it. 

DROP :  See Cloth.

DRUGGET : Canvas or cloth used to mask and/or protect a floor. 

DRY :
1) An actor forgetting the words of his script. 
2) To record a sound without using any effect or other processing is to record it "dry". Recording with an effect is recording "wet". 

DRY ICE : Frozen solid carbon dioxide (CO2) at a temperature of -87.5 degrees centigrade which produces clouds of steam-loaded CO2 gas forming a low-lying mist or fog when dropped into boiling water. Although non-toxic, caution is required in the storage and handling of dry ice because of its extreme cold. Water is boiled in a large tank offstage, into which the dry ice is lowered in a basket. Fans and ducts then direct the gas onto the stage. Dry ice does not support life, so care should be taken that small animals, actors etc. are not below the level of the dry ice for more than a few seconds. 

DRY RUN : A practice run, usually a Technical run without actors.

DRUGGET : A ground cloth, commonly used to protect the floor of a space before installing audience seating etc.

DSM :  Deputy Stage Manager.  

DUBBING : The process of copying a sound from one medium to another (eg onto videotape) or for backup purposes, simply copying sound tapes. 

DUTCHMAN : Tape or material used to cover the seams between flats, prior to painting. 

DYNAMIC MIC : Robust type of microphone which picks up the sound on a diaphragm connected to a coil of wire which moves within a magnet. An alternating current is induced into the wire which provides the electrical output. Most dynamic mics have low output impedances of 200 Ohms. See Condenser Mic. 


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EARTHING : Electrical safety requirement that metal parts of electrical equipment are connected to a common earth or ground point so that in the event of a fault, excess current can be carried away, causing the fuse to blow. Known in the USA as Ground. 

EARTH LOOP :

EARTH SPIKE : Copper rod inserted into the ground to maintain earth continuity (especially when using generators etc.) 

ECHO : A repeated sound received late enough to be heard as distinct from the source. See Reverb. 

EFFECTS, LIGHTING :
Animation Disc : A slotted or perforated metal disc which rotates in front of a lantern to provide "movement" in the light. Most effective when used in front of a profile carrying a gobo. 
Effect Disc : A painted glass disc rotating in front of an effects projector with an objective lens to focus the image (eg Flames, Rain, Snow). 
Flicker Flame : Irregularly slotted rotating metal disc through which light is shone onto a prism-type piece of glass which scatters the beam of light and adds the "dancing" effect of firelight to a scene. 
Gobo Rotators : Motorised device inserted into the gate of a profile lantern that can be remotely controlled to rotate a gobo, usually with variable speed and direction. 
KK Wheel : Slotted metal disc which rotates in front of a lantern to break up the light and provide movement. (Flicker Wheel) 
Lightning : Created through the use of either strobe sources or photoflood lamps.
Tubular Wave Ripple : Horizontal linear lamp around which a slotted cylinder is rotated providing a rising light (as reflected from water onto the side of a ship). 
See also Effects,Sound, pyrotechnics, smoke.

EFFECTS PROJECTOR : Lantern used to project the image from a rotating glass effects disc. Used with an objective lens to produce the desired size of image. Commonly used discs are clouds, flames and rain. 

EFFECTS, SOUND : 
1) Recorded : Often abbreviated to FX. There are many sources for recorded sound effects, most recently on Compact Disc. May form an obvious part of the action (train arriving at station) or may be in the background throughout a scene (e.g. birds chirping). 
2) Live : Gunshots, door slams, and offstage voices (amongst many others) are most effective when done live. See Door slam, Thunder Sheet, Rain box. 
See also Compressor, Digital Effects, Exciter, Noise Gate, Reverb.

EGGS : Slang term used for Strand Pattern 123's, due to their shape.

ELECTRET MIC : A condenser microphone where the capacitor plates are given a charge during manufacture which they retain, therefore requiring no external power supply. 

ELECTRICS : See LX. 

ELEVATION : A working drawing usually drawn to scale, showing the side view of a set or lighting rig. See plan.
In the US, the term "elevation"  refers to a Front elevation. A Rear elevation shows backs of scenic elements. A side view of a set is known as a "section". 

ELEVATOR STAGE : A type of mechanised stage which has sections that can be raised or lowered. 

ELLIPSOIDAL : A profile lantern with an elliptical reflector. Referred to as a LEKO. 

ENHANCER : Sound processing equipment which increases the presence of the vocal track in a mix by adding to the treble information in the signal. Also known as an Exciter. 

ENTR'ACTE : An "overture" to begin the second part or act of a performance. Often used now to describe any interval music. 

EQUALISATION : The process of adjusting the tonal quality of a sound. A graphic equaliser provides adjustment for a wide range of frequency bands, and is normally inserted in the signal path after the mixing desk, before the amplifier. See Feedback. 

EQUITY : Short for British Actors' Equity (or American Actor's Equity Association, founded in 1913, is the labor union representing actors and stage managers in the legitimate theatre in the United States. ). The trade union of actors, directors, designers and stage managers. 
(http://www.equity.org.uk for British, http://www.actorsequity.org/ for American)  

EQUITY LIGHT: See Ghost Light.
 
ESTA : Entertainment Services and Technology Association. 

EXCITER : See Enhancer. 

EXIT SIGN : Usually illuminated sign, of standard size, which should always be visible, showing an audience member and the company the nearest exit. 

EXPANDER : See Noise Gate. 


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FADER : A vertical slider which is used to remotely set the level of a lighting or sound channel. A fade is an increase, diminishment or change in lighting or sound level. 

FALSE PROSCENIUM : A frame formed by scenic canvas or vertical flattage within the proscenium arch. Used to reduce the size of the opening when putting a small set onto a large stage.  

FALSE STAGE : A special stage floor laid for a production. For example to allow trucks  guided by tracks cut into this false floor, to be moved by steel wires running in the shallow (2 or 3 inch) void between the false floor and the original stage floor. A false stage is also required for putting a revolve onto a stage. 

F.B.O. : Abbreviation for Fade to Blackout.

FEED : A power supply to a piece of equipment or installation is termed a "feed". Sound equipment and sensitive computer equipment should have a clean feed - that is, a supply that is free from interference from other equipment. 

FEEDBACK / HOWLROUND : A loud whistle or rumble heard emanating from a sound system. It is caused by a sound being amplified many times. (E.g. a sound is picked up by a microphone and amplified through the speaker. The microphone picks up this amplified sound and it is sent through the system again). Feedback can be avoided by careful microphone positioning, and can be reduced by use of Equalisation to reduce the level of the frequency band causing the feedback. 

FESTOON  :
1) See Swag 
2) Describes tabs which adopt a sculpted shape. 
3) A length of cable incorporating a number of lamp holders used for outdoor party lighting etc. Available in multi-circuit form so that the lamps can be "chased". 

FEV : Short for French Enamel Varnish, a stain which is a mixture of shellac and dye, diluted in methylated spirit. 

FIBRE FRAME : A gel frame made from heat resistant fibres, which doesn't get as hot to the touch as a standard metal frame. 

FIBRE OPTIC : A method of directing light down a very thin glass fibre. Fibre Optics are used mostly in communication, but find theatre applications in star cloths which are black backcloths with the ends of optical fibres poked through, to create a mass of pin pricks of light. A large bundle or harness of fibres may be fed from one light source, sometimes with a motorised colour or flicker wheel. 

FIELD :Refers to the spread of light intensity across a beam. Most profile lanterns have an adjustable field. A Flat field has an even distribution, a peak field has a "hot spot" in the centre of the beam. A flat field is essential when using gobos. See Profile. 

FILL LIGHT : (especially TV and Film lighting) Light which fills the shadows that key light creates. 

FILTER  :
1) See Colour. 
2) Electronic device to isolate and redirect specific frequencies in a speaker system. 

FIRE CURTAIN : See Safety Curtain. 

FIRE EXIT :  Particular exit(s) from a building designated by local authority fire officer to be the correct means of escape from a part of the building in case of fire. It is the responsibility of all staff and performers to ensure that all fire exits are kept clear, unlocked and accessible at all times. 

FIRE EXTINGUISHER : Carbon Dioxide (Black), Water (Red), Foam (Cream), Halon Gas (Green) Powder (Blue) . 

FIRE PROOFING :  Treatment given to fabric, timber, drapes etc. to retard flammability. Many scenic materials require regular re-application of fire proofing treatment. 

FIT-UP :  Initial assembly on stage of a production's hardware, including hanging scenery, building trucks etc. 

FLASH BOX :  A small box containing the socket into which a pyro cartridge is plugged. Also known as a flash pod. 

FLASH OUT / THROUGH : Method of checking whether lanterns are functioning properly by flashing them on one at a time. It is good practice to flash lanterns to 70%, rather than Full to preserve lamp life. 

FLAT : A lightweight timber frame covered with scenic canvas. Now usually covered with plywood or hardboard and consequently not so lightweight. Most theatres have a range of stack flattage made to a standard size, and re-used many times. A Rail is a horizontal batten within a flat. A Stile is a side or vertical piece within a flat. A Sill is the bottom rail of a flat. See also Book flat.  

FLIES : See Fly Tower. 

FLOATS : Early form of footlights using burning wicks floating in oil across the front of the stage. Now applies to anything rigged on the front edge of the stage (eg Float microphones, Uplights etc). 

FLOGGER : Strips of canvas attached to a handle for dusting flats or scenic pieces prior to painting. 

FLOOD :
1) A lensless lantern that produces a broad non-variable spread of light. Floods are used in battens, or singly to light cycloramas or large areas of the stage. 
2) To increase the beam size of a focus spot by moving the lamp and reflector towards the lens. "Flood that a bit, please !" 

FLOORCLOTH : See Cloth. 

FLOORPOCKET : (US) A electrical socket mounted under a flap in the stage floor (UK equivalent is "dip").
  
FLOOR PLAN : See Plan. 

FLUFF : To hesitate - to nearly forget or fumble one's lines.

FLUORESCENCE : The property of some materials to glow when subjected to Ultra-violet light. The materials degrade the UV wavelengths into longer and therefore visible reflected rays. See also Phosphorescence. 

FLY BARS : The metal bars to which scenery and lanterns are attached for flying above the stage. 

FLY FLOOR(S) : High working platform at the side(s) of the stage from which the flying lines are handled. Often are also the site for socket panels for connecting flown lighting apparatus to dimmers, and also sometimes a lighting position. Known in the US as Fly Gallery. 

FLY GALLERY : See Fly Floor.

FLYING : See Hemp Set, Counterweight System.  

FLY TOWER : Extension of the stage walls up to allow scenery to be flown up until it is out of sight of the audience. Known as the "flies". The ideal fly tower should be more than twice the height of the pros. arch, and is said to have "full flying height". Known in the US as the Fly Loft. 

FOCUS : The session when all the lanterns in the rig are angled in the correct direction, with the correct beam size. 

FOCUSING : The process of adjusting the direction and beam size of lanterns. Does not necessarily result in a "sharply focused" image. 

FOCUS SPOT : Term for both Fresnel and PC type lanterns with adjustable beam size. 

FOG MACHINE : See Smoke Machine.

FOH : See Front of House. 

FOLDBACK : Means by which musicians can part of the rest of the sound mix (including voices) and how their instruments sound after being amplified. Also enables actors on stage to hear musicians or effects when they cannot hear the output of the auditorium sound system. 

FOLLOW-ON CUE : A cue that is timed to follow an original cue so quickly that it does not need a separate cue number. Often abbreviated to f/o. 

FOLLOW SPOT : Usually, a powerful profile lantern usually fitted with its own dimmer, iris, colour magazine and shutters mounted in or above the auditorium, used with an operator so that the light beam can be moved around the stage to follow an actor. Sometimes a beam light or other lantern may be used in the same way. See limes. 

FOOTLIGHTS : A compartmentalised batten sometimes recessed into the front edge of the stage, used to neutralise shadows cast by overhead lighting. Modern lighting equipment renders footlights virtually obsolete except for period/special effects. 

FORESTAGE : That part of the stage which projects from the proscenium into the auditorium. See Apron. 

FRENCH BRACE : See Brace . 

FRENCH FLAT : A scenic flat which is flown into position, usually with French braces. 

FRENCH SCENE :A scene division within a play marked (as in French drama) by the entrance / exit of an actor.

FREQUENCY : (measured in Hertz - Hz - cycles per second) The number of times a sound source vibrates each second. A high frequency (HF) sound has a higher pitch and is uni-directional. A low frequency (LF) sound has a lower pitch and is omnidirectional. 

FRESNEL  :(pronounced "Fre-nell")  A type of lantern which produces an even, soft-edged beam of light through a Fresnel lens. The lens is a series of stepped concentric circles on the front and pebbled on the back and is named after its French inventor, Augustin Jean Fresnel (1788-1827). 

FRONT CLOTH : A cloth flown well downstage in front of  which short scenes are played while big scene changes are  "silently" carried out upstage. (Common in musicals and pantomime). 

FRONT OF HOUSE (FOH) :
1) Every part of the theatre in front of the pros arch. Includes foyer areas open to the general public. 
2) All lanterns which are on the audience side of the proscenium and are focussed towards the stage. 

FRONT OF HOUSE CALLS : Announcements made by stage management or FOH staff calling the audience into the auditorium, or informing them when the performance begins. Calls are normally made at the Half (35 mins. before curtain up), the Quarter (20 mins before), the Five (10 mins), and calls normally accompanied by bar bells at 3, 2 and 1 minutes before the performance begins. 

FRONT TABS : House curtains. 

FROST : A diffusing filter used to soften the edges of a light beam. Different strengths of diffuser are available from many colour filter manufacturers. See silk. 

FULLERS EARTH : : Hydrous aluminium silicate, used in chemistry as a filter 
and as a binder when mixing powder paint for use on textiles. 

FULLNESS : Draperies made up with deep "gatherings" have fullness - usually requiring not less than 50% additional fabric, measured at head and foot.  

FUSE : Protective device for electrical equipment (E.g. dimmers). The fuse link will melt  when excess current flows, preventing damage to people or equipment. Every piece of electrical equipment has at least one fuse in its associated circuit. 
 
FUZZ LIGHT : A lamp with a revolving mirror and a coloured plastic dome. Gives a "police light" effect. Usually 12 Volt or 240 Volt operation. 

FX  : See Sound Effect. 


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GAFFA TAPE : Ubiquitous sticky cloth tape. Most common widths are .5" for marking out areas and 2" (usually black) for everything else. Used for temporarily securing almost anything. Should not be used on coiled cables or equipment. Originally known as Gaffer's Tape, from the Gaffer (Master Electrician) on a film set. See PVC Tape. (101 Uses for Gaffa Tape) 

GAIN : 
1) The level of amplification given to a signal or of a system. 
2) A control of the amount of pre-amplification given to a sound signal on its way into a mixer. 

GATE  :
1) The point of focus in a profile spot where the shutters are positioned and where an iris or gobo can be inserted. 
 2)  A single base section of a folding rostrum system. 
 3)  See Noise Gate. 

GAUZE : Cloth with a relatively coarse weave. Used unpainted to diffuse a scene played behind it. When painted, a gauze is opaque when lit obliquely from the front and becomes transparent when the scene behind it is lit . Many different types of gauze are available ; Sharkstooth gauze is the most effective for transformations, because it is the most opaque. Vision gauze is used for diffusing a scene and for supporting cut cloths. Also known as a Scrim. 

G-CLAMP :  Ironmongery fitting for clamping two items into position together. See also Hook Clamp. 

GEL or Gelatine : See Colour Filter. 

GENERAL COVER : Those lanterns in a rig which are set aside purely to light the acting areas. The stage is normally split into a number of areas for this purpose, which can then be isolated or blended together as required by the director. See Special. 

GERB : See pyro. 

GET-IN : The process of moving set, props and other hardware into a theatre prior to the fit-up. (aka Load in or Bump in) 

GET-OFFS : A means for an actor to get off a rostrum, high level etc. out of view of the audience. Usually treads. 

GET-OUT : Moving an entire production out of the venue, and into either a large waste-disposal skip, or into transport. Usually preceded by the strike. (aka Load out or Bump out.) 

GHOSTLIGHT : A light left burning overnight on stage to keep friendly spirits illuminated and unfriendly spirits at bay. Also believed to keep the theatrical muse in a "dark" theatre, and to stop people tripping over bits of scenery when they come into the theatre in the morning. Also refers to the light emitted by a lantern when a dimmer has not been "trimmed" correctly, and is leaking. Also known as "Equity Light".

GLASS FIBRE : A combination of a glass mat and a resin which can be formed into a strong shell. Used in prop-making. 

GLAZE : Glossy finish applied as a final coat to a painted stage floor (also available as a Matt / Flat finish). 

GLOVES : Used when lifting heavier lanterns. 

GLS : General Lighting Service. Lamps designed for general everyday use. 

GOBO : A thin metal plate etched to produce a design which can then be 
projected by a profile spotlight (E.g. Foliage, Windows). 
The image can be used soft focus to add texture, rather than a defined image. 
A number of composite gobos in different coloured lanterns can, with careful focusing, produce a coloured image (e.g. a stained glass window). 
Greater detail can be achieved using a glass gobo. 
The original use of the word GOBO came from the early days of Hollywood.  When the Director of Photography wanted daylight excluded from some area of the set, he'd say "GO BlackOut". Loads of people would run around putting black material between the sun and the set. It eventually evolved into other stuff that goes in front of lights and now most commonly (in the UK at least), refers to patterns in profiles.
In the US TV/Film industry, a Gobo is a piece of material used to mask or block light and a 
Cookie (short for Cucaloris(from the Greek kukaloris: the 
breaking up of light)) is the same as a UK Gobo. 

GOBO HOLDER  : A metal plate designed to hold a gobo of a particular size in a lantern of a particular type. 

GOBO ROTATOR : See Effects. 

GODS : Colloquial term for the Upper Circle of the auditorium. 

GRAND CIRCLE : See Circle. 

GRAND MASTER : See Master. 

GRAPHIC EQUALISER : See Equalisation. 

GREASEPAINT : Name refers to make up supplied in stick form, for application to the face or body. Needs special removing cream. 

GREEN (obsolete term) : The part of the stage visible to the audience. 

GREEN ROOM : Room close to the stage (i.e. the green) for the actors to meet and relax. More.... 

GRELCO :  Brand name for a 2 way 5A or 15A electrical splitter. Another name is Snapper. Sometimes shortened to Grelly. 
A three way splitter is known as a Trelly. 

GRID : 
1) The support structure close to the top of  the fly tower on which the pulleys of the flying system are supported. Constructed from metal or wooden beams. 
2) Arrangement of scaffolding from which lanterns are hung in a performance space with no flying facilities. 

GRIDDED : Any flying piece raised as high as possible into the flys, i.e.to the limit of travel of the flying lines, is said to have been gridded. 

GROUND PLAN : Scaled plan showing the exact position (seen from above) of all items standing on the stage floor and indicating the position of items suspended above. Typical scales are 1:24 (.5" to 1 foot) or, metrically 1:25 (1cm to .25m). Venues have a base plan showing proscenium, walls, seating etc on which individual set and lighting plans can be drawn. 

GROUNDROW : 
1) A long piece of scenery positioned at the base of a backcloth usually to mask the very bottom of a cloth or lanterns lighting a cloth. 
2) Compartmentalised floodlight battens at floor level used to light the bottom of skycloths etc. 

GROUP : A subdivision, permanent or optional, of a lighting board control preset, or a sound desk. 

GUN MIC : A highly directional condenser microphone.


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HALF : Call given to the actors half an hour before they will be called to the stage for the beginning of a performance. Given 35 minutes before the advertised time of commencement. Subsequent calls given are the "quarter" at 20 minutes, "the five" at 10 minutes and "beginners to the stage" at 5 minutes before curtain up. See also Front of House Calls. 

HALOGEN CYCLE : Chemical process occurring in Tungsten Halogen lamps which makes them possible. During the lamps life, Tungsten evaporates from the filament, and would normally deposit itself on the glass wall of a Tungsten lamp, causing it to blacken, and causing the output of the lamp to reduce until it finally blew. In a Tungsten Halogen lamp, the Tungsten combines with the Halogen gas elements present in the lamp envelope and is re-deposited back onto the filament. This process needs a very high temperature to operate, so Tungsten Halogen lamps are able to be a lot smaller, and run a lot hotter, than their Tungsten equivalents. See also Tungsten Halogen. 

HANGING IRON : Ironmongery fitting fixed at the bottom of the back of a flown flat to which the suspension wire is secured. 

HAZER : See Smoke Machine.

"HEADS ON STAGE" : A shouted warning (often just "Heads !") for staff to be aware of activity above them. Also used when an object is being dropped from above. 

HEADSET : 
1) General term for theatre communication equipment. 
2) A headphone and microphone combination used in such communications systems with a beltpack. 

HEMP : A type of rope used for flying, made from fibres found within the bark of the cannabis plant. 

HEMP SET : The simplest flying system consisting of a series of hemp ropes threaded through pulleys on the grid, and tied off on the fly floor on a cleat. The usual arrangement is for three ropes to be attached to a flying piece, named by their position relative to the fly floor (short, centre and long). These names are used when levelling the flying piece, and giving it a dead. The three ropes are pulled or let in together, sometimes requiring more than one person to operate. A theatre using a hemp flying system is known as a Hemp House. 

HIGH HAT : See Top Hat.

HINGE : See Pin Hinge, Backflap Hinge. 

HMI (Hydragyrum Medium arc-length Iodide) : A mercury-halide discharge lamp with a colour temperature of 5600K (daylight). 

HOOK CLAMP : A clamp with a wing bolt for hanging a lantern on a horizontal lighting bar. See safety chain and boom arm. 

HOUSE : 
1) The audience (eg "How big is the house tonight ?") 
2) The auditorium (eg "The house is now open, please do not cross the stage") 

HOUSE LIGHTS : The auditorium lighting which is commonly faded out when the performance starts. 

HOWIE BATTEN: (After Howard Eaton) This is a two circuit (two colour) 120V per circuit MR16 batten developed by Howard for lighting cloths at close proximity. A row of these hung above a cloth allow you to light the cloth where there is little space. They have also become popular as footlights.

HOWLROUND : See Feedback. 

HYDRAULIC : A system of controlling machinery or moving scenery using oil or water under pressure to move a piston or "ram". Used in many large-scale shows to automate scene changes.  

HYPER CARDOID : See Pick-Up. 


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IEC:  International Electrotechnical Commission

IMPEDANCE :  A term for the electrical resistance found in a/c circuits. Affects the ability of a cable to transmit low level (e.g. sound) signals over a long distance. Measured in Ohms. Speakers are rated according to power handling capabilities (Watts, W) and impedance (Ohms).

INCANDESCENT : Light source consisting of a metal filament (Tungsten) which glows white hot when current is passed through. See also Discharge Lamp.

INDEPENDENT : 1) An electrical power supply that is totally separate from the stage lighting control. Used for testing lanterns prior to connection to the lighting system and also for powering non-lighting equipment on stage and working lights. See Non Dim.
2) A channel within the stage lighting control which has been temporarily switched to become independent from the rest of the channels which remain under the control of the operator.

INDUCTION LOOP : System which amplifies audio frequency currents (from a microphone over the stage) around a large loop of cable (around the auditorium) to generate a magnetic field which can be picked up by a hearing aid switched to the "T" position.

INFRA RED Invisible part of the electromagnetic spectrum with a longer wavelength than visible light. Infra-red remote controls are used for lighting desks and practicals. An infra-red-sensitive CCTV camera can pick up body heat activity even in a "blackout".

INHIBIT : A way of taking control of a rogue lantern (or lanterns) at the lighting desk during the operation of a show and removing them from any further lighting states, until the inhibit is removed. Can also be used for removing the front of house lighting from a curtain call state.

INSERT : 
1) An additional route into a sound desk.
2) An extra lighting state added into the sequence later. See Point Cue.

INSET : A small scene set inside a larger one.

INTELLIGENT LIGHT : See Moving Light.

INTERNALLY WIRED BAR (IWB) : A Scaffolding bar (aluminium) which has a number of sockets (usually 15A) positioned along its length, the wiring for which is contained within the bar. See Six Lamp Bar.

INTERVAL MUSIC : Music played in the foyer and/or auditorium during intervals. Most usually Vivaldi's Four Seasons.

INVENTORY : A numbered packing list which itemises all single pieces travelling on a tour; all cartons, flightcases, crates, baskets together with quantities and descriptions of contents.  Extremely important if touring abroad to satisfy customs. Dimensions/weight/value may also require recording.

IRIS : Adjustable aperture which, when placed in the gate of a profile lantern, varies the size of a beam of light. Originally, iris diaphragm.

IRON : See Safety Curtain.

INTERCOM : Usually refers to microphone/headset communications equipment. Abbreviated to "comms". Also known as "cans".


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JACK : 
1)Segmented audio connector. Mono Jacks have two connections - tip and sleeve, and are unbalanced. Stereo jacks have three connections - tip, ring and sleeve. B-type jacks (also known as Bantam jacks) were originally designed for use in telephone exchanges and provide a high quality (and expensive) connection in jackfields. A-type jacks are cheaper and more common, but more fragile. A type jacks are available in 2 sizes : quarter inch and eighth inch.
2) (US) A hinged brace. In the open position, it holds up a flat or other unit of scenery. A Tip Jack is a combinaton of a 
jack and castors so scenery can be supported or rolled.  When it is in position, it is tipped to vertical.  When rolling, it leans backwards.

JACKFIELD : An array of jack sockets ("jills"), providing connections to equipment/outlets etc. A patch panel.

JUMPER : An adaptor from one type of electrical connector to another. For example, a 13 - 15A jumper has a 13A plug and a 15A socket at either end of a short cable. Also applicable to sound cables.


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KABUKI DROP : Method for dropping a cloth from a flying bar. It consists of a bar which attaches to a 
standard flying bar, and is able to spin around. The bar has prongs welded to it on which the drop is hung 
(drop has grommetted holes in the top which hook onto the prongs). Normally these prongs 
are above horizontal, so the drop stays hung. On cue, the pole is 
rotated so that the prongs point downwards, and the drop consequently falls.

KELVIN : See Colour Temperature.

KEY LIGHT : (Esp. TV & Film lighting)  The dominant light source/direction in a lighting state. In a sunny drawing room, the key light would be through the window, for a naturalistic exterior scene the direction of the key light could change as the sun progressed across the sky. See Fill Light.

KILL : To switch off (a light/sound effect); to strike/remove (a prop).

KILOWATT : 1 kilowatt (1kW) is equal to 1000 Watts

KIT :General name for equipment, especially nice shiny equipment, leading to the comment "That's a nice bit of kit"

KK WHEEL :A type of animation disk which fits into the colour runners at the front of a lantern which rotates and breaks up the light beam to make it appear to be moving. Best used on a profile lantern containing a gobo.

KVA : Kilo-Volt Amps. Unit of electrical power.


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LADDER : Non-climbable structure in the shape of a ladder from which lanterns can be hung in a vertical "stack".

LAMP : What the un-initiated call a light bulb. See also Bubble.

LAMPY : Theatre / Rock & Roll lighting technician. Distinct from a "Techie" who may also be a carpenter or stage crew member. A lampy only concerns him/herself with lighting. See also Techie and Noise Boy

LANTERN : 1) General term for unit of lighting equipment including spotlight, flood etc. Term now being replaced by the  internationally recognised "luminaire".

2) Glazed section of roof usually in haystack form over the fly tower that automatically opens in the case of  fire. An updraught is created which inhibits fire from spreading quickly into the auditorium, and prevents build-up of smoke at stage level.

LASER : Acronym of Light Amplification by Stimulated Emission of Radiation. A very high energy beam of light that remains virtually parallel throughout its length. Visible in the air only when a haze of smoke or dust is introduced. Great care is required when using lasers as this energy can cause permanent damage to the retina of the eye. 

LAVALIER MICROPHONE : Originally, a mic worn around the neck on a string. Now applies to a small "tieclip" microphone.

LD :  Lighting Designer.

LEADER TAPE : Non-magnetic plastic tape used to begin and end sound tapes and to separate cues on tape. Clear leader tape is used to activate the automatic stop on some playback machines. Leader tape is available in a variety of colours.

LEGS : Drape set as masking piece at the side of the acting area. Usually set up in pairs across the stage and used in conjunction with borders to frame the audiences view. Apparently, the origin of the phrase "Break a Leg", meaning to take an extra encore from the legs after a successful performance.

LEKO : A type of ellipsoidal profile spot, much used in the USA. Contraction of the original manufacturers names.

LEMO : A small metal multipin connector used for connecting radio microphone heads into the transmitter pack.

LENS : Optical glass with one or both sides curved, the purpose of which is to direct light by concentrating or dispersing light beams.

LIBRETTO : Text of opera, or other long musical vocal composition. The script of a musical.

LIFT : The orchestra pit and/or sections of the stage may be mounted on lifts to make moving of heavy items (e.g. piano etc.) easier. Sometimes the forestage doubles as the orchestra pit by use of a lift.

LIGHT CURTAIN : A lighting effect which, when an area is diffused with smoke, produces a wall of light. Produced (usually) by a batten of low voltage PAR lamps wired in series. Automated versions are available which have colour changers built-in and are able to tilt up and down.

LIGHTING PLAN : A scale drawing detailing the exact location of each lantern used in a production and any other pertinent information (E.g. its dimmer number, focus position and colour number). Often drawn from the theatres' groundplan.

LIGHTING PLOT : The process of recording information about each lighting state either onto paper or into the memory of a computerised lighting board for subsequent playback.  (in USA, this term is used for a lighting plan and a lights session is when lighting states are set up.)

LIGHTING STATE : The format of lighting used at a particular point in the production; a lighting "picture".

LIGHTING STENCIL : Plastic stencil containing a range of scale symbols for current lighting equipment. Greatly facilitates the drawing of lighting plans.

LIMELIGHT : An obsolete source of intensely bright light, most recently used in followspots. See limes. Derived from a burning jet of oxygen and hydrogen impinging on a rotatable cylinder of lime.

LIMES : Follow spots and their operators. This term is still in everyday use, although limelight is not. 

LIMITER : See Compressor.

LINE LEVEL SIGNAL : "Standard" level at which the inputs and outputs of domestic and professional sound equipment operate. Slight variations are that some equipment works at +4dB, some at -10dB. See Mic Level Signal.

LINE-UP TONE : Signal of known frequency and level used for setting up sound recording equipment levels accurately.

LINK : See Point Cue.

LINNEBACH PROJECTOR : Lensless system for projecting a shape from a gel or glass slide etc. placed in front of a floodlight onto the set. Often used for shadow effects.

LOAD :
1) The electrical power rating, in Watts, of the equipment connected to a particular lighting dimmer.
2) The equipment connected to a dimmer.

LOAD STRAP : Woven strap with a ratchet tensioner used for securing a load in a lorry.

LOADING BAY : Access into the theatre for scenery and other equipment. Also called the Get In.


LOGE: Seating area in traditional pros. arch venues. Exact location varies according to the venue, but is usually a "box" position at the dress circle level. (From the French Logè) 

LOUDSPEAKER : Device for converting the electrical signal from an amplifier back into sound waves, most commonly by vibrating a paper cone. Most speaker systems are composed of a number of sources - each designed to handle a specific range of frequencies. See Tweeters and Woofers, Bi-Amplification.

LOW VOLTAGE : Lower voltage lamps give more intense light than mains voltage lamps of the same wattage.

LUAN (US) : A flexible 3 ply timber, used for cladding flats etc. Also known as Philippine mahogany. Use is declining due to the fact that it is sourced from environmentally unsustainable resources in the Brazilian Rainforest.

LUMEN : A measure of light output from a source.

LUMINAIRE : The international term for lighting equipment. Not restricted to theatre lighting.

LUX : A measure of the level of illumination on a surface (1 lumen spread over 1 metre).

LX : Short for Electrics. The department in the theatre responsible for stage lighting and sometimes sound and maintenance of the building's electrical equipment.

LX TAPE : See PVC tape.


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MAHL-STICK : A short stick used by scenic painters to steady the hand by resting its padded end against the surface being painted.

MAINTAINED LIGHTING : See Secondary lighting.

MANUAL DESK : A lighting desk where the interface between operator and dimmer is a fader, rather than a computer. Many modern manual desks have some memory facilities built in, but there are still a large number of venues with solely manual systems.

MARIE TEMPEST HINGE: Door hinge that has been reinforced by a screw lever to keep the door from opening by itself on a raked stage. Named after an actress.

MARKING OUT : Sticking tapes to the floor of the rehearsal space to indicate the groundplan of the scenery. Also for marking position of furniture etc. within a set.

MAROON : An electrically detonated pyrotechnic device giving the effect of a loud explosion. 
Made from gunpowder encased in stout cardboard or string. Must be used within a metal bomb tank. 
Originally developed in the second half of the last century to simulate the sound of cannon. 
It was often used to call out the volunteer lifeboat crew in an emergency.

MASKING : Neutral material or designed scenery which defines the performance area and conceals the technical areas. (e.g. Masking flat).

MASKING TAPE : Paper sticky tape used to mark out the boundary of a surface to be painted or sprayed.

MASTER :
1) An overall control on a lighting or sound control board. The Grand Master takes precedence over all other controls. See Submaster.
2) An original (e.g. Master tape, master plan) which should be used only to make a copy from which to work.
3) A Department Head (e.g. Master Carpenter, Master Electrician). 

MATRIX OUTPUT : Set of outputs on a mixing desk which allows the user to preset a number of output configurations. eg on a 8 x 8 matrix, each of the 8 group outputs from the channels can be routed to any or all of the matrix outputs.

MCB : Minature Circuit Breaker. Up to 63A. See Fuse.

MCCB : Moulded Case Circuit Breaker (over 63A). See Fuse.

MD : 
1) Musical Director. Often the conductor/leader of a musical, or the person responsible for the musical content of a production.
2) Mini Disc. See Digital Recording.

MDF : Medium Density Fibreboard.

MEATRACK : Wheeled rack for transporting a number of pre-rigged six-lamp bars or lanterns.

MEMORY BOARD : An electronic storage device which enables recording and subsequent "playback" of lighting states.

MIC : (pronounced "Mike") Abbreviation for microphone.

MIC LEVEL SIGNAL :Low level audio signal produced by circuitry in microphone. Needs boosting either by a pre-amp or a mixing desk before it can be amplified. Susceptible to interference over long cable runs.

MICROPHONE : Device for converting sound into electrical pulses which can then be amplified or recorded onto tape. Signals from a microphone are very low level and are amplified in the mixing desk to line level. 
See Dynamic Mic, Condenser Mic, Phantom Power, Pick-up, Radio Mic.

MICROPHONE CAPSULE : An interchangable microphone head that fits onto a pre-amplifier. Many capsule types are available, all of which fit the same pre-amplifier.

MIDI : Musical  Instrument Digital Interface. Control system for linking musical instruments or other electronic equipment and computers together and storing the control signals the equipment produces for subsequent playback. See MSC and MMC.

MIMIC : The VDU associated with most medium and large lighting desks has a detailed mimic of the level of all dimmers and other associated information.

MINI DISC : See Digital Recording.

MIRROR BALL : A lighting effect popular in ballrooms and other dance halls. A large plastic ball covered with small mirror pieces. When a spotlight is focused onto the ball, specks for light are thrown around the room. Usually motorised to rotate. [Picture]

MIXDOWN : The process during which a multitrack recording is balanced and transferred to two tracks (stereo) for playback or reproduction.

MIXER : A desk comprising a number of input channels where each sound source is provided with its own control channel through which sound signals are routed into two or more outputs. Many mixing desks can also change the quality of the sound (see Equalisation). A Powered Mixer has an amplifier built into it. Sound sources of varying levels are accepted which can be amplified if necessary. (See Line Level, Gain).

MMC: MIDI Machine Control. A variation of the MIDI language designed for controlling mechanical equipment (eg Tape Players).

MODEL : A scale model provided by the set designer to help all the technical departments to co-ordinate and plan a production. Used as a reference when building, painting, dressing and lighting the set.

MONITOR :
1) An onstage speaker which allows a performer to hear the output of the PA system, or other members of a band.
2) A video display screen

MONKEY POLE : A stick threaded at one end with the line used to cleat two adjacent flats together, enabling the flats to be quickly and silently joined or separated. The stick remains attached to the line and flat of which it forms part.

MOON BOX : Lighting effect. A large shallow circular box with calico on one face and low wattage lamps arranged on the back. Can be flown behind a gauze or thin cyclorama to give the effect of the moon rising. 

MSC : MIDI Show Control. A control language which is an extended version of the original MIDI language. In addition to a "go" command, cue numbers and other information can be sent as well (in addition to fault reports and safety checks).

M.S.R. : (Medium Source Rare Earth) High efficiency discharge lamp with a high colour temperature.

M.U. : Musicians Union.

MULTICORE : A flexible electrical cable composed of several well-insulated cores covered in a strong PVC or rubber covering. Enables a number of different circuits to be carried down one piece of cable. Both lighting and sound multicores are available.

MULTIPLEXED (MUX) SIGNAL : All modern lighting desks use this serial form of communication with dimmers. All the information from the desk is transmitted along a single pair of cables to the dimmer where a de-multiplexing unit (demux box) decodes the string of data and passes the correct piece of information to the correct dimmer. The inductry standard protocal (language/standard) for multiplexing is the digital USITT DMX512. However, new protocols are continually being added to keep up with more demanding equipment. SMX is a communications protocol which enables digital dimmers to "report back" to the desk on any faults (eg blown lamps). D54 uses a stream of analogue voltage levels and was the Strand standard before DMX512 arrived.


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NAB : National American Broadcast. Standard for tape recording equalisation characteristics.

NEON :
1) A type of discharge lighting generated by a high voltage across two electrodes at opposite ends of a long, thin glass tube filled with neon gas. Different colours can be obtained by mixing other gases, or by using fluorescent coatings. Mostly used for advertising signs - the glass tube is bent to form letters.
2) A small mains voltage indicator lamp.

NEUTRAL DENSITY FILTER : (ND) Lighting filter which reduces the brightness of a light source without changing its colour.

NOISE BOY : Theatre or concert sound engineer. Normally male. But not exclusively so ! See also Techie and Lampy.

NOISE GATE : A piece of sound processing equipment that reduces background noise by muting a sound signal when it falls below a certain level, restoring it when the level increases again. Must be used on vocal microphones with care, because it may cut the signal off, although the vocalist is still singing quietly. Also known as an Expander.

NON DIMS : Channels, usually controlled from the lighting desk which are switched, rather than dimmed. This enables motors, slide projectors, smoke machines etc to be controlled from the lighting desk.


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O.P. : Opposite Prompt side of the stage. Stage Right. (ie Actors right when facing audience).[Diagram]

OFFSTAGE :1) A movement towards the nearest side of the stage from the centre. (e.g. "Focus that spot offstage a bit please")2) The area out of sight of the audience (e.g. "Get that donkey offstage !")

OHM : The unit of electrical resistance.

OISTAT : International Organisation of Theatre Scenographers, Technicians and Architects.

OMNIDIRECTIONAL : See Pick-up.

ONSTAGE : A movement towards the centre of the stage from the sides.[Diagram]

OPEN THE HOUSE : Clearance given to FOH staff by stage management that the stage is set and the audience can begin to take their seats. When this clearance is given, the backstage call "The House is now open, please do not cross the stage" is made.

OPEN WHITE :  (o/w) Lighting with no colour filter.

OUT : In flying, means up (out of sight).

OUTRIGGER : An extendible leg to increase the stability of access equipment (eg Tallescope, Scaffold tower).


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PA SYSTEM  :  See Public Address System

PAD  :  A switch on a mixing desk input channel which attenuates (reduces the level of) a signal.

PAGING  :  The act of holding a tab etc. back to allow large items or actors offstage. Also preventing microphone etc cables from getting entangled by pulling / releasing them from offstage as performer walks around.

PAINT FRAME  :  Large vertical wooden frame from which cloths are hung for painting. The frame is often winchable for easy access.

PAIRING  :  Connecting more than one lantern to one power outlet via an adaptor or splitter, or more than one speaker to one amplifier channel.

PAPER THE HOUSE  :  Marketing technique. Giving away tickets to a performance (eg Opening Night) to make a show seem to be selling better than it actually is.

PAR  :  Short for Parabolic Aluminised Reflector lamp. A lamp containing a filament, reflector and lens in one sealed unit. Used in Parcans to produce a high intensity narrow beam of light. Par lamps are available in many different sizes and powers. Par sizes available include 16, 36, 38, 56 and 64. (The number refers to the diameter of the lens, in eighths of an inch). The most common for theatre use are Par 64s rated at 1000W (1kW), although other wattages are available.

PARABOLIC REFLECTOR  :  See Par.

PARALLEL : 1) The folding frame that forms the base of a readily portable platform.
2) The opposite of SERIES when referring to wiring two loads into one outlet.

PARAMETRIC EQ  :  Equalisation control where the range of frequencies to be boosted or cut can be selected. Allows the "fine-tuning" of the equalisation.

PASS DOOR  :   A fire-resisting door in the wall of the proscenium arch which is the only correct access between the auditorium and the stage.

PASSIVE  : See Active.

PATCHING  :  

1) To cross-connect lighting circuits around the stage area to a chosen dimmer. Connecting lanterns to dimmers.

2) Using a cross-connect panel which enables any stage lighting channels to the control desk to control any dimmer or group of dimmers. Some large lighting boards have the facility for soft patching - a totally electronic way of patching. Some Rock Desks have a pin patch which allows groups of dimmers to be allocated to a particular control channel. Also applies to routing of sound signals.

PATCH PANEL  :  A board consisting of rows of sockets into which plugs can be connected to route sound signals or power for lighting circuits.

PATTERN NUMBER  :  Many older Strand lanterns are identified by their Patt. number (eg Patt.23 is a 500W profile). The numbers bear no direct relation to their size or type (although lanterns of a similar design may have similar Pattern numbers.) See http://www.strandarchive.co.uk for a full listing.

PC  :  Originally short of plano-convex - the basic lans shape of many lanterns / projectors. Now short for Prism- or Pebble-convex: a type of lens with a pebbled flat surface which gives a slightly harder edge than a Fresnel, but not as hard as a Profile. PC refers to a lantern with a PC lens.

PCC  :  Phase Coherent Cardoid. See Boundary Mic.

PD's (Per Day)  :  A daily payment by an employer to touring technicians to cover daily living expenses. This is additional to the monthly / weekly wage.

PEBBLE SPOT  :  See PC.

PERCENT  :  Dimmer levels are expressed as a percentage of the supply voltage. (100% = 240 Volts(UK)).

PERCHES  :  Lighting positions (often on platforms) at each side of the stage, immediately behind the proscenium.

PERIAKTOI : Greek term for three-sided flats mounted on a rotating base. Used in rows to produce easily changed backings.

PERSONAL PROPS  :  See Props.

PFL  :   See Pre-Fade Listen.

PHANTOM POWER  :  Some condenser microphones require a power supply in order to operate. If this supply is not from a battery within the microphone body, it is known as a phantom power supply. It is usually 48 Volts DC (can be 9 - 52 volts from most mics), and is supplied either by a separate battery pack, or by the sound desk. The supply is termed "phantom" because it is "invisibly" carried down the same microphone cable as the sound signals. 

PHASES  :  Electricity is generated and supplied to large installations in three phases. Each of the Red, Yellow and Blue phases are supplied down one cable to the building, but effectively give three separate supplies. Because there is a potential difference (voltage) of 415 volts between two phases, care must be taken that pieces of equipment powered by different phases are not capable of being touched at the same time in case of a fault.

PHONO PLUG  :  An unbalanced audio connector used for connecting line-level equipment together (eg CD player, tape recorder). Unsuitable for professional use due to lack of durability. Also known as RCA Connector.

PHOSPHORESCENCE  :  The property of some materials that can store light energy and glow in the dark.

PHOTOFLOOD  :  A lamp used by photographers which gives a bright white light. Because it has a thin filament, it gives a good flash effect (eg lightning), but has a relatively short life, so should not be left on for any length of time.

PIANO DRESS  :  Rehearsal in costume and with all technical facilities but using a piano as a substitute for orchestra, so that the director can concentrate on technical problems rather than musical ones (and not pay the orchestra !).

PICK-UP  :  
1) Device which, when attached to an acoustic musical instrument, converts sound vibrations into an electrical signal.
2) A way of describing the directional sensitivity of a microphone. An Omnidirectional microphone has equal pick-up from all around, a Cardoid microphone  is more sensitive from the front, a Hypercardoid has very strong directionality from the front. A figure-of eight microphone picks up front and rear, but rejects sound from the sides.

PIN HINGE  :  Hinge with removable pin used to join two pieces of scenery together (ie one half of the hinge is on each piece of scenery).

PINK NOISE  :  Random sounding audio noise containing all frequencies in the audio spectrum tuned to the response of the human ear. Used with a Spectrum Analyser to set equalisation equipment for a large PA installation. However, the human ear is still a better judge of how a system sounds. See also White Noise.

PIN PATCH  :  See Patching.

PIN SPOT  :   
1) A lantern focused very tightly on a small area (eg an actors head)
2) A luminaire used widely in disco installations, consisting of a low voltage Par 36 lamp with a fine beam in a metal case with built in transformer.

PIPES  :  US term for the bars on which scenery and lanterns are flown.

PIT  :  The area housing the orchestra. Originally, a lower section between the front of the stage and the audience, although now describes any area around the stage housing the musicians.

PITCH CONTROL  :  Facility on some sound playback devices for changing the speed of playback, and thus the pitch or frequency of the sound, to match an existing sound, or to fit a particular timeslot. Some Professional CD players have tempo controls which speed up the playback, and then compensate for the resulting increase in frequency using a pitch change. This results in the ability to match the beat of a CD in a disco situation, without the "Pinky and Perky" effect.

PLAN  :  A scale drawing showing a piece of scenery, lighting layout etc from above. Lighting plans are usually drawn onto the theatre's groundplan.

PLASA   :  Professional Lighting and Sound Association (UK)

PLATE REVERB  :  Reverb effect produced using a large metal plate. A signal is supplied to an acoustic transducer at the edge of the plate, causing vibrations which are picked up by transducers at other locations on the plate. This type of reverb can be simulated by some digital effects units.

PLAY AS CAST  :  Contract drawn up for an actor when casting is not complete.

PLAYBACK  :  The part of a computerised lighting control desk which enables the operator to recall cues from the electronic memory.

PLOT  :  List of preparations and actions required of technical crews during the performance (eg Sound Plot = list of sound cues and levels in running order.)
In the US, the term plot refers to a plan. (eg Light Plot = scale plan showing lighting instruments)

PLOTTING SESSION  :  Time during which the plot for each department is prepared (eg Lighting Plotting session)

PLY  :  Short for Plywood.

POINT CUE  :  A cue inserted during / after plotting between two existing cues. (eg 8.5 is inserted between cues 8 and 9 and cues by the stage manager as 8A). Most computer lighting desks have the ability to either insert an additional cue in a sequence, or to link to another cue out of the sequence, and then link back again. Inserting cues into a plotted sequence on a manual lighting desk is more awkward, because it is a running plot (where only the changes between cues are noted down).

POLE OPERATION  :  A mechanical means whereby pan (horizontal rotation), tilt (up and down) and focus of a lantern may be adjusted by a pole from floor level. Commonly used in TV & Film studios where fast resetting of postions is necessary.

POP SCREEN  :  A thin gauze screen placed between a singer and a microphone to reduce vocal "popping" and other breath noise.

POP SHIELD  :  A foam shield placed over the end of a microphone to reduce the pick up of vocal "popping" and external wind noise.

PORTAL  :  An archway made by combining wings/legs and border. Also a decorative framing, columns and pediments or filigree or other that frames the stage.

POWER AMPLIFIER  :  Converts sound signals of line level (approx 1 volt) into tens of volts, with currents of around 1 Amp to drive speakers.

PPM  : (Peak Programme Meter) Meter, often with green/red LED's, giving an accurate indication of the electrical nature of an audio signal (see also VU).

PRACTICAL  :  Any object which appears to do onstage the same job it would do in life, or any working apparatus (eg light switch or tap). An electrified prop.

PRE-FADE LISTEN  :  Often shortened to PFL. Control on a sound mixing desk which allows the user to check the presence of a signal, and its quality before bringing up the fader. Also vital for fault-finding, where the route of a signal can be PFL'ed around the desk until the point where the fault occurs. Also known as Check and Cue.

PREFADE / POSTFADE  :  An output from a sound desk is said to be prefade if it is independent of the channel fader. If it is postfade, the level of the output is relative to the channel fader.

PREFOCUS CAP  :  A type of lamp base which ensures that the filament is correctly lined up relative to the reflector and lens.

PREHEAT  :  Smoother lighting builds from zero are achieved when a lamp filament has been warmed (at approx 15%) in the previous state.

PRESET  :  
1) Anything in position before the beginning of a scene or act (eg Props placed on stage before the performance, lighting state on stage as the audience are entering.)
2) An indepenently controllable section of a manual lighting board which allows the setting up of a lighting state before it is needed. Each preset has a master fader which selects the maximum level of dimmers controlled by that preset.

PREVIEW  :  A function on some memory lighting control desks with video mimics. Preview enables the operator to see the levels of dimmers and other information in a lighting state other than that on stage.

PRIMARY COLOURS  :  The primary additive colours of light are red, green and blue, and the subtractive colours are cyan, magenta and yellow.

PRODUCTION DESK  :  Table in the auditorium at which director/designer etc sit during rehearsals (especially technical rehearsals). Usually has its own lighting and communications facilities.

PRODUCTION MANAGER  :  Responsible for technical preparations, including budgeting and scheduling of productions.

PROFILE  : 
1) Shaped piece of scenery added to the edge of a flat instead of a straight edge. Also known as a cutout.
2) A type of lantern with at least one plano-convex lens which projects the outline of any chosen shape placed in its gate, sometimes with a variable degree of hardness/softness. Profiles include four beam-shaping metal shutters, a gate to take an iris or gobo and an adjustment to make the beam smooth and even ("flat") or hot in the centre ("peaky"). See Bifocal Spot, Zoom Profile.

PROJECTION  : 
1) Slides are used to project still archive images or textures. Libraries of slides contain images for every occasion. Kodak Carousel projectors are the industry standard, and some types can be linked to a controller to perform complex dissolves and fades from one projector to another. More powerful projectors are available using very intense discharge sources and large format glass slides to produce a massive image.

2) Lighting effects : Moving cloud / rain / fire effects can be achieved using a powerful lantern known as an effects projector with a motorised glass disc painted with the required effect. An objective lens is required in front of the disc to focus the image. See Effects.

3) Gobos : See Gobo.

4) Film : 35mm film projection is common in many theatres as a device for keeping the building open to the public when productions are in preparation. 16mm film projection is used in smaller venues. Film projection can, of course, also be integrated into a performance.

5) Video : Video projection is now being used to bring television pictures to the large screen. Cheaper than using film, but the image quality is not as good. Video projection equipment can also be more difficult to set up.

Images can be front projected or back/rear projected depending on the amount of space and the effect required. For example, if actors are required to walk in front of the screen and not have the image appearing on them, back projection is the only answer. See Screen.

PROMPT BOOK  :  Master copy of the script or score, containing all the actor moves and technical cues, used by stage management to control the performance. Sometimes known as the "book". 

PROMPT CORNER  :  Area, traditionally on the stage left side of the stage, from which the stage manager (or DSM) controls ("prompts") the performance, from the prompt desk.

PROMPT DESK  :  The control centre of the show. The desk should contain most of the following: a clock, low level lighting, a flat surface for the prompt script, communication facility to other technical departments, a phone for emergency, rear and front of house calls system and cue light controls.

PROMPT SIDE (PS)  :  Usually stage left side of the stage, containing the prompt corner. [Diagram]

PROPPING  :  The task, usually performed by stage management, of going around finding / borrowing / buying props for the production.

PROPS  :   (Properties) Furnishings, set dressings, and all items large and small which cannot be classified as scenery, electrics or wardrobe. Props handled by actors are known as handprops, props which are kept in an actors costume are known as personal props.

PROPS TABLE  :  Table in convenient offstage area on which properties are prepared prior to a performance and to which they should be returned after use.

PROS.ARCH  :  Short for Proscenium Arch.

PROSCENIUM ARCH  :  The opening in the wall which stands between stage and auditorium in some theatres; the picture frame through which the audience sees the play. The "fourth wall".

PROTOCOL  :  See Multiplex.

PSU  :  Power Supply Unit.

PUBLIC ADDRESS SYSTEM  :  The venue auditorium sound system. Usually shortened to "PA".

PUBLICITY  :  The department in the theatre whose job it is to entice the audience into the theatre, and to tell them what they need to know in order to get the most from the production.

PULL :The amount of electrical power required by a touring show in a venue.

PUNCH IN  :  A facility on multitrack recorders which allows you to "drop in" a sound onto a track whilst playing through the tape, sometimes controlled by a footswitch. Useful for correcting mistakes in an already recorded tape.

PUSH AND PULL  :  Actors who have to move scenery / furniture around the stage, earning them extra money. Slang term is Pickfords, after the UK Furniture removals company.

PYROTECHNICS  :  (Pyro) Chemical explosive or flammable firework effects with a manual detonation. Usually electrically fired with special designed fail-safe equipment. Types of pyro range from the Theatrical Flash (a flash and a cloud of smoke) to the Maroon (which produces a very loud bang). A Gerb is a version of the Roman Candle firework, throwing a shower of sparks into the air. All pyrotechnics should be used with close reference to local licensing laws, and the manufacturers instructions.

PVC TAPE  :  Plastic insulating tape used for taping cables to bars and for securing coiled cables. Neater and cheaper than Gaffa tape. Also known as LX tape.

PZM  :  Pressure Zone Microphone. See Boundary Microphone.


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QUADROPHONIC  :  A sound system which uses four independent speakers (or sets of speakers). The fore-runner of today's Surround Sound. See Stereophonic.

QUARTZ HALOGEN  :  See Tungsten Halogen.

QUICK CHANGE ROOM  :  Area adjacent to the stage containing lighting, a mirror and a costume rail in which actors can make costume changes quickly, sometimes with the aid of a dresser.


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R & V : Reich and Vogel. German manufacturers of low voltage beamlight. Now used to describe any beamlight.

RACK  :  A cabinet of standard width (19") into which various components can be bolted. Racks are ideal for touring equipment, are neat, and they allow easy access to the rear and front panels.

RADIO CONTROL  :  System whereby battery-powered practicals / props on stage can be controllable from offstage with no connecting leads.

RADIO MIC  :  Device consisting of a microphone head, transmitter pack with batteries, aerial and mains receiver unit which allows actors and singers to be amplified with no visible means of connection. Almost universally used in musicals where the singers have to be amplified to be heard over the orchestra / band. Used in non-musical shows for sound reinforcement.

RAIL  :  1) See flat. 
2) Same as Flyrail.

RAIN BOX  :  A box or tray containing dried peas etc which produces a rain sound effect when inclined.

RAKED STAGE  :  A sloping stage which is raised at the back (upstage) end. All theatres used to be built with raked stages as a matter of course. Today, the stage is often left flat and the auditorium is raked to improve the view of the stage from all seats. A rake is expressed as a ratio (eg a 1:25 rake rises by 1cm vertically over 25cm horizontally). See also Anti-Rake.

RAT STAND : Illuminated music stand (named after manufacturer ?).

RCA : See Phono Plug.

RCD  :  Residual Current Device. Protects the user against short circuit (earth faults) and earth leakage caused by damaged cable or faulty equipment. A RCBO is a combined MCB and RCD, protecting against earth leakage/short circuit and overload.

REAR OF HOUSE (ROH)  : The backstage and storage areas of the theatre.

REAR PROJECTION  : See Projection.

REPERTOIRE  :  A form of organisation where two or more productions alternate in the course of a season.

REPERTORY  :  A form of organisation, usually with a permanent company of actors, where each production has a run of limited length. At any time, there is normally one production in performance, another in rehearsal and several others in varying degrees of planning.

RE-RIG  :  To change the lighting rig after the last performance of one show to the positions for the next show.

RESISTANCE DIMMER  :  A now obsolete method of dimming which decreases the current available to the load by introducing a variable resistance between supply and load. The excess current is converted into heat. Based around a rheostat.

RETROFIT  : A modification that can be made to an existing piece of equipment after purchase to bring it up to date.

RETURN  : 

1) Flats joined to the DS edge of flats of a set or unit that "return" into the wings.  They help mask and also keep the DS edge of a set from looking raw.
2) A financial report given to theatre management staff by the box office manager on a daily or weekly basis setting out the takings for performances.
3) Route for an auxiliary signal back into a sound mixer.

REVEAL  :  A return which is at right angles to a flat, and suggests the thickness of a window, wall, doorway etc.

REVERB  :  (Reverberation) Effect which may be added to sound effects during recording or to a voice during performance. Sustains the sound longer than normal, as if the sound was reverberating around a large building (eg cathedral). Persistance of sound after the source has ceased.

REVOLVE  : A turntable built into the stage floor on which scenery can be set and then driven into view. Can be electrically chain driven, or manually pushed into position. A revolve can also be built on top of an existing stage.

REVOX  :  Brand name of the once industry standard reel to reel tape recorder. Still enormously popular and universally known.

RF :  Radio Frequency

RFU : Remote Focus Unit. A remote control for the lighting desk. Same as RIGGERS CONTROL.

RIAA  : Record Industry Association of America. The standard equalisation to be applied to a signal from a record deck pick-up. Phono pre-amps have RIAA circuitry built-in.

RIBBON MIC :  Delicate mic not suitable for high sound pressure levels. Consists of a corrugated conductive foil strip suspended between opposing magnetic poles which is excited by pressure differences between the front and rear of the microphone and induces a current.

RIDER  : (Technical Rider) Information sent to a venue by a touring group detailing lighting, sound, staging and dressing room requirements. Ideally arrives before the group !

RIFLE MIC  : See Gun Mic.

RIG  : 
1) The construction or arrangement of lighting equipment for a particular production.(noun) 
2) Installing lighting, sound equipment and scenery etc for a particular show.(verb) 

RIGGERS CONTROL  : A remote control for a lighting desk which enables dimmer channels to be called up from the stage when rigging or focusing. Usually battery powered, sometimes with infra-red (cordless) control. A Designers Control allows whole memories to be called up and/or played back, as well as individual dimmers.

RIGGING  : 
Spanset : Woven strap designed to be wrapped around girders and other structural support points. Has loops at each end to which a shackle carrying a suspension cable can attach. Available in a number of different loads.

RISER :  
1) Any platform on stage.  For instance, the series of platforms for choral presentations are called choral risers, the rostrum on which a drumkit and drummer is positioned is the drum riser.
2) The vertical portion of a step which gives a set of treads its height.
3) A microphone which can be raised through a small trap in the stage floor to a convenient height for an actor. Usually positioned just upstage of the footlight position, centre stage.

ROAD MANAGER (ROADIE)  : A touring technician with one night shows, particularly music groups. Large groups will have a roadie in charge of a particular instrument or set of instruments (eg Guitar Roadie, Drum Roadie, Lager Roadie) who is responsible for the correct unloading and setting up (tuning etc) of the instruments before the artists arrive onstage for the sound check.

ROCK DESK :  Lighting control desk designed for rock concerts, the main feature of which is the ability to group a set of dimmers under the control of a series of flash buttons, enabling the operator to "play the lights" in time to the music. These desks usually have a very good lighting effects capability.

ROH (Rear of House)  : The backstage areas of the theatre.

ROLL DROP (US) : Cloths flown on rollers.

ROLLER  : A system whereby cloths can be rolled up/down instead of flying in/out in a theatre where there is no fly tower, or limited flying height.

ROSTRUM  : (plural ROSTRA) A portable platform, usually in the form of a collapsible hinged framework (Gate) with a separate top (Lid).

ROYALTIES : The prescribed fee paid to an author or his agent for the performing rights of a play.

RUCHE  : (pronounced ROOSH) A pleating or gathering of cloth / drapes.

RUN  : A sequence of performances of the same production.

RUNNING PLOT :  A plot giving details of the changes between cues, as distinct from a state plot which gives the whole state of the system at any time. For example, a lighting plot on a manual board is normally a running plot. It is difficult to start a running plot half way through; often the operator has to go back to the beginning and work through until the required point is reached.

RUNNERS 
1) A pair of curtains parting in the centre and running horizontally, particularly those used in a downstage position in variety and revue productions.
2) Persons employed as production assistants to do odd jobs and errands during a production period.
3) Strips of carpet used backstage to silence actors' shoes during performance.


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SAFETY CHAIN : Chain or wire fixed around lantern and lighting bar or boom to prevent danger in the event of failure of the primary support (eg Hook Clamp). A requirement of most licensing authorities.

SAFETY CURTAIN : A fireproof curtain that can be dropped downstage of the tabs to separate the audience from the stage in the event of fire. A Safety Curtain is required by most licensing authorities for theatres over 500 seats. The regulations also require that it is raised and lowered at least once in view of each audience (usually during the interval). Usually made from sheet metal and electrically operated, used to be made from iron faced with asbestos and lowered using a hydraulic damping system. Colloquially known as the "iron". See also Drencher.

SAMPLING : The technique of recording a sound digitally (translating the analogue audio waveform into a series of electrical ons and offs that can be manipulated by a computer) for subsequent processing, editing and playback.

SAND BAG : Attached to an unused spot line to stop it running back through the pulleys, and to enable it to fly in without fouling adjacent equipment.

SATURATION RIG : An arrangement of lanterns in which to maximum number of spotlights is placed in every possible position.

SBTD : Society of British Theatre Designers.

SCENE DOCK : High-ceilinged storage area adjacent to the stage, sometimes used for building and storing flats and other scenery.

SCENIC PAINT : Traditionally, a mixture of glue size, water and pigment. Modern practice has also adopted PVA (emulsion glaze) as a bonding medium which can be used when scenery has got to be washed and used again.

SCENOGRAPHER : Designer responsible for all the visual aspects of a production (lighting, scenery, costumes etc).

SCREEN (PROJECTION) : Many types of projection screen are available. Some are multi-purpose, some only for front projection, some only for back projection. If a screen is not self-supporting, it often has eyelets around the outside edge which are used to "lace" the screen onto a larger frame.

SCREW EYE : A threaded metal ring screwed to the rear of a flat for securing a stage brace.

SCRIM :
1) A coarse gauze
2) A fine metal mesh used to reduce the intensity of light from TV lanterns without affecting colour temperature.

SCROLLER : See Colour changer.

SECONDARY LIGHTING: Separately powered lighting system for use throughout the building in the event of failure of the primary system. Usually battery powered. Maintained lighting is on all the time, regardless of changes in the stage lighting, and is battery backed-up.

SECTION: See Elevation.

SEGUE (pronounced "segway") : Musical term for an immediate follow-on. Often used as jargon for any kind of immediate follow-on.

SEMAPHORE : See Colour Changer.

SEQUENCING : A act of recording digitally and manipulating the MIDI information required to remotely play a synthesizer keyboard or similar device.

SERIES SPLITTER : An adaptor consisting of a plug and two sockets wired in series. Enables two identical 110 Volt loads to be safely run from a 240 Volt supply (UK).

SET : 
1)  To prepare the stage for action. (verb)
2)  The complete stage setting for a scene or act. (noun)

SET BACK : To reset technical systems to a particular point in the show in order to repeat a sequence or scene during rehearsals.

SETTING LINE : Imaginary line running across the width of the stage, in line with the proscenium arch, which is marked on the groundplan and is used as a reference when planning furniture layouts etc. Usually the furthest downstage anything can be set without fouling the house tabs. See also Centre Line.

SFX : Abbreviation for Sound Effects.

SHACKLE : See Rigging.

SHEAVE : The wheel in a pulley which carries the wire or rope.

SHIFTER : The common Australian term for AJ's, c-wrenches etc.

SHIN BUSTER : The lowest lantern on a lighting boom. Named because of the proximity of sharp parts of the lantern to the flesh of the lower leg.

SHOW RELAY : A network of speakers carrying the sound of the show, and sometimes stage managers calls, to the furthest reaches of the theatre. 

SHOW REPORT : A written report by stage management giving problems, running times, show staff and audience numbers for the previous days' performance(s). Copies are circulated to the technical departments and management staff.

SHUTTER : Accessory for a profile lantern. Metal blade which can be used to shape the edge of the beam. Shutters (normally four) are located in the gate at the centre of the lantern. Similar in effect to barndoors. 

SIGHTLINES : A series of lines drawn on plan and section to indicate the limits of the audience vision from extreme seats, including side seats and front and back rows. Often marked in the wings as a guide to the actors and crew.

SILK : A special type of diffusion filter which stretches the light in one direction. Especially useful for lighting large cycloramas with a limited number of lanterns, or for lighting an elongated object (eg a staircase) with one lantern. 

SILL : See Flat. 

SILL IRON : A piece of flat iron screwed to the bottom rail of a door flat which holds it together, and ensures that the flat doesn't warp. Invisible to the audience. 

SINGLE PURCHASE : Counterweight flying system where the cradle travels the same vertical distance as the fly bar. The counterweight frame therefore occupies the full height of the side wall of the stage. See also Double Purchase. 

SITZPROBE : The first rehearsal between Opera singers and the orchestra.  No attempt is made to act or move the production at this rehearsal.

SIX LAMP BAR : An internally-wired lighting bar, designed for touring, with six socket outlets terminated in a multi-way connector. Often pre-rigged with lanterns (eg Parcans). Stored in Meatracks.

SIZE : See Scenic Paint.

SLIDE : See Projection.

SKIN MONEY : Extra payment made to actors/actresses when nudity is required on stage.

SKIP (Costume/Props): A large wicker basket or box, often wheeled, which stores costumes and/or props for touring.


SMA - (UK) Stage Management Association who also publish the Freelist - a list of stage management available for work.

SMOKE MACHINE : A Smoke Machine or Fogger is an electrically powered unit which produces clouds of white non-toxic fog 
(available in different flavours/smells) by the vaporisation of mineral oil. It is specially designed for theatre & film use. A Haze machine, or Diffusion Fogger is used to produce an atmospheric haze, rather than clouds of smoke, and is used by many lighting designers to reveal airborne light beams. See also Cracked Oil, Dry Ice.

SMOKE POCKET : A vertical steel channel on the upstage edges of the poscenium arch in which the edges of the fire curtain travel.

SMPTE (pronounced "Simptee"): Society of Motion Picture and Television Engineers. A timecode for synchronising a piece of music etc on a tape to almost anything else.

SNAP : A lighting or sound cue with no fade time - the cue happens instantly.

SNAP HOOK : A plastic or metal "S" hook used to hang tabs etc. A sprung catch prevents the hook becoming detached.


SNAP LINE : Chalked piece of string which, when stretched tight and "snapped" is used for marking straight lines on stage or on scenery as a painting aid.

SNAPPER : See Grelco.

SNUB : US term. To sieze the lines on a flying piece to prevent it's movement, either with another rope or with a mechanical line locking device.

SOCA : See Socapex.

SOCAPEX : A multipin connector which can carry a series of lighting or sound circuits. Very robust and designed for touring. Available in 19 and 37 pin configurations.

SOFT LIGHT : Asymmetric flood light used as a fill light in TV studios to eliminate shadows and balance the key light.

SOUND CHECK : A thorough test of the sound system before a performance. This will include checking each speaker cabinet individually, and each playback device. In the case of a live concert, this is the session when each instrument is played in turn for the sound engineer to check and fine-tune the sound.

SOUND EFFECT : See Effect, Sound.

SOUND REINFORCEMENT : Amplifying a voice just enough so that it can be heard, without the audience being aware that it is being amplified (ideally !).

SOUND TO LIGHT : A facility which can link the effects panel on a lighting board to an audio input which detects treble, mid and bass beats, and can flash lights or trigger effects in time to those beats.

SPANSET : See Rigging.

SPARKY : See Lampie.

SPEAKER : See Loudspeaker.

SPEAKON CONNECTOR : A type of shielded, locking multipin speaker connector which can safely carry the high currents from an amplifier needed to drive large speaker systems. Available in 4- or 8-way types, and ideal for bi-amplified systems. The cable version of the connector is male, and the panel mount connector is female.

SPECIAL : A lantern within the lighting rig which is required for a specific moment or effect within the performance, and is not part of the general cover lighting.

SPIDER : Adaptor to connect many lanterns to one multicore cable. Consists of multipin connector (typically Socapex or Lectriflex), short length of cable, then a number of sockets related to the number of circuits in the cable.

SPIGOT : An adaptor screwed onto the hanging bolt of an instrument to enable it to be used on an upright stand.

SPILL : Unwanted light onstage.

SPILL RINGS : Concentric rings attached to the front of a beamlight (eg Strand Pageant) to contain spill.

SPIKE : To mark the position of an item of set/furniture on stage. Spike Tape is normally thin gaffa tape, although PVC Electrical tape is used on precious floors. Sometimes, any securing of cable etc to floor is known as "Spiking".

SPL (Sound Pressure Level) : A measurement of the loudness of a sound.

SPLICE : A join or edit in a sound tape. A splice may be between leader tape and audio tape or between two pieces of audio tape. Splicing tape is the adhesive tape used, a splicing block is used to hold the tape and guide the single-sided razor blade when making the cut.

SPLITTER : See Adaptor.

SPOTLIGHT : General term for any lantern with a lens system. See Fresnel, PC, Profile.

SPOT LINE : A temporary line dropped from the grid to suspend something in an exact special position.

SQUELCH : Control on a radio microphone receiver for fine-tuning the reception according to the surroundings.

STAGE ELECTRICIAN : Member of the electrics staff whose responsibility it is to set or clear electrics equipment during scene changes. May also carry out colour changes on booms etc.

STAGE LEFT / RIGHT : Left/ Right as seen from the Actor's point of view on stage. (ie Stage Left is the right side of the stage when looking from the auditorium.) 
Stage Right = OP (Opposite Prompt) Fr.: Coté Jardin, Netherlands: Toneel 
Links (translates to Stage Left!)
Stage Left = PS (Prompt Side) Fr.: Coté Cour, Netherlands: Toneel 
Rechts (translates to Stage Right!)
[Diagram]

STAGE MANAGER :
1) The Head of the Stage Management team comprising the deputy stage manager (DSM) and assistant stage manager (ASM). The DSM is normally "on the book" calling the cues from the prompt corner. The ASM supervises props. Depending on the needs of the production, there may be a team of stagehands, usually casual employees.
2) A software program by Richmond Sound Design which, via MIDI Show Control, can be set up to "run the show".

STAGE SCREW : A large screw which is screwed through the "foot" of a stage brace to secure it to a strong wooden floor. Only suitable for use in theatres with non-precious wooden floors !

STAGE WEIGHT : See Brace Weight.

STAGGER-THROUGH : The first tentative attempt to run through the whole show. Very rarely runs smoothly, hence the name.

STALLS : The lowest audience seating area, usually just below the level of the stage, in a proscenium theatre.

STAND-BY : A warning given to technical staff by stage management that a cue is imminent. Technicians acknowledge by saying "Standing By". 

STARCLOTH : See Cloth.

STATE : In lighting terms, a lighting "picture" ; each lighting cue results in a different state (or a modified state).

STEP : A control on some lighting effects boards which enables the operator to "step" through a chase effect in time to music etc.

STILE :  See Flat. 

STRIKE : To take down a setting; to take down properties or lanterns.

STRIPLIGHT : A thin linear filament lamp similar to an Architectural, but having contacts at the ends of the lamp. Available clear or opaque.

STROBE : Device giving a fast series of very short intense light flashes which can have the effect of making action appear intermittent. Because strobe lighting can trigger an epileptic attack in sufferers, the use of a strobe must be communicated to the audience before the performance begins. Regulations exist governing the maximum length of time for which a strobe can be used.

SUPERSTITION: Theatrical people are notoriously superstitous. There are many rules which some people swear by related to working in the theatre. 1) Backstage whistles were originally used to give instructions to the sailors who (because they knew the best knots) had the job of operating the theatre's flying system. Nowadays, whistling is forbidden backstage because it might result in a lost sailor cutting a rope and dropping something on somebody. 2) Mentioning Macbeth in a theatre is said to invoke the curse of the Scottish Play. The only way to break the curse is for the offender to spin on the spot and then spit. This is an approximation to a purification ritual. The spin turns back time, and the spit expels the corrupting poison. 3) Saying Good Luck is not allowed backstage. The term "Break a Leg" is used. See the separate page about this ! 

SWAG :  1) A particularly artistic way of drawing a set of tabs diagonally up at the same time as flying them out. Looks much better than it sounds. 2) Souvenirs given to crew following a particular show or event, usually in the form of T-shirts, posters & coffee mugs.

SWING :  A member of the company of a musical who understudies one of the leads and is also in the chorus, but doesn't have a character name in the chorus.

SWARBIES:   3 or 4 , 500 or 1000 watt flood lamps mounted on a wooden skid,used as cyclorama bottom lighting or in between scenery groundrows. Probably derived from German theatre lighting company, Schwabe.

S.W.L. : Safe Working Load. The maximum weight that should be put onto a lifting device or suspension point. Now superseded by WLL (working Load Limit)

SUB-BASS :  That part of a speaker system designed to extend the low frequency range of the system.


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TABS : Originally "tableaux curtains" which drew outwards and upwards, but now generally applied to any stage curtains including a vertically flying front curtain (house tabs) and especially a pair of horizontally moving curtains which overlap at the centre and move outwards from that centre.

TAB DRESSING : Lighting focused onto the house tabs.

TAB-TRACK : Track for suspending and operating horizontally moving curtains. May be hand or winch operated.

TAKE-UP SPOOL : The empty reel on the right hand side of a reel to reel tape deck onto which is wound the tape as it plays through the machine.

TALLESCOPE : A retractable alloy vertical ladder on an adjustable wheeled base. The platform at the top is just large enough to hold one person. Used for rigging lanterns, focusing etc. Collapsible enough to fit through a standard doorway. Outriggers are used to stabilise the tower from falling sideways. Two people are used to move and steady the tallescope. Sometimes known as a "TALLEY".
 
TAPE LOOP : A continuous loop of tape which produces an "everlasting" sound effect when played. Used for any long sound needed (eg rain, wind) without having to continuously repeat a short effect.
 
TAT : (slang) Small (but still useful) offcuts of cloth or wood.
 
TEASER : Border, usually black, set behind the proscenium and linked with tormentors to form an inner frame to the stage, and to mask the upper parts of the fly tower.

TECHIE : A stage technician. For more information, see The Techie Gospel. See also Lampy and Noise Boy.
 
TECHNICAL REHEARSAL : Usually the first time the show is rehearsed in the venue, with lighting, scenery and sound. Costumes are sometimes used where they may cause technical problems (eg Quick changes). Often a very lengthy process. Often abbreviated to the Tech.
 
TECHNICAL RIDER : See Rider.
 
THROW : Distance between a light source (e.g. lantern or projector) and the actor or object being lit.
 
THROW LINE : A rope used to hold adjacent flats together as one via cleats.
 
THRUST : Form of stage which projects into the auditorium so that the audience are seated on at least two sides of the extended piece.
 
THUNDER RUN : Long channel down which a cannonball is rolled to give a realistic thunder rumble effect. Built into the roof of some older theatres, but mostly now unused (for safety reasons).
 
THUNDER SHEET : Large suspended steel sheet with handles which produces a thunder-like rumble when shaken or beaten.
 
TIME : The facility on memory lighting boards for playing back timed fades at the touch of a button.
 
TOP HAT : Also known as High Hat. Cylinder of metal inserted into colour runners on the front of a parcan or other lantern to limit spill light.

TOPPING AND TAILING : See Cue to Cue.
 
TORMENTORS : Narrow masking flats adjacent and sometimes at right angles to the proscenium arch.
 
TRANSDUCER : A device that converts energy from one form to another. A microphone is a transducer that converts sound wave energy into electrical pulses.
 
TRANSFORMATION : An instant scene change, often effected by exploiting the varying transparency of gauze under different lighting conditions.
 
TRAP : An opening through the stage floor. A grave trap is a lowered rectangular section used in Hamlet etc. A cauldron trap is a simple opening through which items can be passed into a cauldron on stage. A star trap is a set of triangular sprung flaps in the stage floor through which an actor can be propelled from a lift below stage. 
The Vampire Trap was invented for James Planche's 1820 adaption of Polidori's The Vampyr. It involved two spring leaves that parted under pressure and immediately reclosed. Placed in the floor or stage wall, it could give the impression a figure was passing through solid matter.  
The Corsican Trap, made for Dion Boucicault's 1852 adaption of Alexandre Dumas'
The Corsican Brothers, involved an ascending track, on which a wheeled cart could be run, rising up out of the stage through a 'bristle' trap - a trapdoor covered with bristles painted to match the scenery. Once on the stage and in view, the track was covered by a sliding arrangement reminiscent of that of a roll- top desk; towhit, nothing was seen except the ghost rising up through the floor and gliding across the stage. 
(Vampire Trap and Corsican Trap definition from http://www.drcasey.com/cabinet/timeline/stage.shtml "The Cabinet of Dr Casey")
 
TRAP ROOM : The area directly below the trapped part of the stage. Used for accessing the traps. 
 
TRANSOM :
 
TRANSVERSE :  Form of staging where the audience is on either side of the acting area.
 
TRAVELLERS : Curtains or scenic pieces moving on horizontal tracks.
 
TREADS : General name for any stage staircase or set of steps. The step of the staircase is called the tread, and the height of the staircase depends on the number of risers. The length of the staircase is called the going. Treads can be either open or closed string - meaning whether the riser is solid or not.
 
TRIPE (bundle) : Bunch of cables tied or taped together into a single unit.

TRIM : US for DEAD on a flying piece.
 
TRIPPING : US for TUMBLING a cloth that can't be flown out of sight.

TRS :
1) Tough Rubber Sheath. Applied to any rubber-sheathed mains cable.
2) Tip Ring Sleeve. The three contacts on a stereo jack audio connector.
 
TRUCK : Wheeled platform on which a scene or part of a scene is built to facilitate scene changing.
 
TRUNNION ARM : U-shaped bracket between the hook clamp and the main body of a lighting instrument, enabling it to be tilted to any angle.
 
TRUSS : A framework of alloy bars and triangular cross-bracing (usually of scaffolding diameter) providing a rigid structure, particularly useful for hanging lights where no permanent facility is available.
 
TUBULAR WAVE RIPPLE : See Effects.
 
TUMBLING : Flying a cloth from the bottom as well as the top when there is insufficient height to fly it in the normal way. See TRIPPING.
 
TUNGSTEN HALOGEN : A standard tungsten filament lamp loses its brightness in its' lifetime. Tungsten Halogen lamps use a Quartz envelope ("bulb") filled with halogen gas to give an almost constant colour temperature. See Halogen Cycle.

TURN :Techie name for an Actor/Artiste. ("What time does the turn get here?")

TWEETER :Part of a speaker system designed to handle the high frequency part of the signal.
 
TWIRLIES : Derogatory (or not ?) term for performing members of a ballet group.


U    Back To Top


ULTRA VIOLET (UV) : Short wavelength source of light at the end of the visible light electromagnetic spectrum which causes specially treated materials to fluoresce on an otherwise blackened stage. Used for special effect and for lighting onstage technical areas (eg Fly Floors). Ultraviolet sources designed for stage use are known as Black Light sources and have all harmful radiations filtered out.
 
UPSTAGE :
1) The part of the stage furthest from the audience.
[Diagram]
2) When an actor moves upstage of another and causes the victim to turn away from the audience he is "upstaging". Also, an actor drawing attention to himself away from the main action is upstaging. 

UNCLE BUDDY : US Term. A type of steel snubbing device, also called a LINE-LOK, named after its' alleged inventor.

USITT :United States Institute of Theatre Technology.


V    Back To Top


VAC FORMING : Vacuum forming is a process of reproducing architectural and textural relief detail on sets by forming a thin plastic sheet into the required shape by a suction process.

VALENCE : US term for a TEASER attached to the main house tabs.
 
VARI*LITE : Trade name for a range of "intelligent" moving lights.
 
VIDEO : See CCTV.
 
VISUAL CUE : A cue taken by a technician from the action on stage rather than being cued by the stage manager. Often abbreviated to "Vis".
 
VOLTAGE : The pressure at which electric current is available. The UK standard voltage is 240 Volts. The American standard is 110 Volts.
 
VOMITORY : An entrance or exit through banked seating. Often abbreviated to Vom.
 
VPLT :German Professional Lighting and Sound Association.
 
VU METER : (VU - Volume Unit). Pointer and scale meter which indicates the average level of a signal. Misses any transients and spikes that lead to a clipped signal. See PPM.


W    Back To Top


WAGON STAGE : Mechanised stage where the scenery is moved into position on large sliding trucks (wagons) as wide as the proscenium opening, from storage in large areas to the side and rear of the main stage. This system enables incredibly complex and otherwise time-consuming scene changes to occur almost instantly.
 
WARDROBE : The general name for the costume department, its staff and the accommodation they occupy.
 
WARDROBE PLOT : Actor-by-actor, scene-by-scene inventory of all the costumes in a production, with a detailed breakdown into every separate item in each costume.
 
WATER CRACKER : Device which produces a thin haze in the air by "cracking" water droplets. 
 
WATTS : Unit of electrical power derived from the current (or "quantity" of electricity) multipled by the voltage (or "pressure" at which the current is delivered). Stage lighting equipment is rated in Watts (or Kilowatts - 1kW being equal to 1000W). This refers to the amount of power required to light the lamp. A higher wattage lamp requires more power and gives a brighter light output.
 
WAVELENGTH : The distance from one point on a vibrating wave to the same point on the next wave. The lengths of the sound waves (wavelengths) we can hear range from one inch to 40 feet. High frequency sounds have short wavelengths (and are more directional), low frequency sounds have long wavelengths (and are less directional). In lighting terms, blue light is short wavelength, green is medium and red is long wavelength. Beyond visible light are the short wavelength Ultra Violet light and the long wavelength Infra Red light. See also Frequency.
 
WEDGE : A wedge-shaped foldback speaker. Angled so that it can sit on the stage floor and point up at musicians/cast.
 
WEIGHT : See Counterweight and Brace Weight. Also, instruction given to rookie stage crew on errand to hardware supplier ; "Go and get me a long weight".
 
WHISTLE : Backstage whistles were originally used to give instructions to the sailors who (because they knew the best knots) had the job of operating the theatre's flying system. Nowadays, whistling is forbidden backstage because it might result in a lost sailor cutting a rope and dropping something on somebody.
 
WHITE NOISE :  
 
WIGGLY MIRRORS : Slang for so-called "Intelligent" lights with moving mirrors.

WINGS : 
1) The out of view areas to the sides of the acting area.
2) Scenery standing where the acting area joins these technical areas.
 
WIPE : Single curtain moving across the stage on a single track (wipe track) rather than paired curtains on a tab track.
 
WIRE ROPE : Fine steel wires woven into a rope to give great strength. A kink or a knot in wire rope greatly reduces the strength.
 
WOOFER : Part of a speaker system designed to handle the low frequency parts of the signal.
 
WORKING LIGHTS :
1) High wattage lights used in a venue when the stage / auditorium lighting is not on. Used for rehearsals, fit-up, strike and resetting.
2) Low wattage blue lights used to illuminate offstage obstacles and props tables etc. Known as Wing Workers.
 
WORKSTATION : A synthesiser keyboard which also contains a sequencer and other MIDI software.


X    Back To Top


X : Stage management abbreviation for "crosses to".
 
XFADE : See Cross Fade.
 
XLR : Multipin metallic audio connector. (3 pin for normal sound use, 5 pin for DMX, Colour Scrollers etc). Sometimes called Cannons after the original manufacturer. See balanced line. The UK standard for wiring the 3 pin connector is as follows : Pin 1 (Screen), Pin 2 (+ve / "hot"), Pin 3 (-ve, "cold"). (Xternal, Live, Return).


Y    Back To Top


YOKE : The TRUNNION ARM of a lantern.

YO-YO : A device used for remotely moving a gobo in one plane whilst it is in the lantern. Gives the effect of a lateral movement (door opens, train passes etc.)


Z    Back To Top


ZERO DB : The common reference point when discussing sound levels. Levels above 0dB are expressed as positive (+5dB) and those below as negative (-20dB).
 
ZOOM PROFILE : A type of profile lantern with two lenses enabling the adjustment of both size of the beam and whether it's hard or soft focus. Essential when working with gobos.





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Compiled by Jon Primrose at 
University of Exeter Drama Department
http://www.ex.ac.uk/drama/

With assistance from
Phil Cameron, David Edmund, Jim Haney, Maurice Marshal, Anthony Richards

Many thanks to the contributors to internet newsgroup rec.arts.theatre.stagecraft


Email corrections / additions to J.G.Primrose@ex.ac.uk

The information contained in this Glossary is provided on the web for the purposes of 
research and education. Any part of it may only be produced electronically or on paper
if the source is acknowledged, including this statement :

This listing is copyright © 1996/99 Jon Primrose / Exeter University Drama Department.
The most up to date version can always be downloaded from http://www.ex.ac.uk/drama/tech/
Exeter University Drama Department information : http://www.ex.ac.uk/drama/" 

Last updated 13th February 2000  Jon Primrose

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