A glossary of terms covering lighting, audio, vision and staging in the event and theatrical industry.
There can be a number of meanings for some terms which can vary from country to country and manufacturer to manufacturer. Information within this guide is indicative and every situation can require a different approach and solution. All care has been taken, however, Image Group NZ accepts no responsibility for inaccuracies. If you have any suggestions, comments or queries regarding this list please contact us.
See CHEAT SHEET.
See SECONDARY LIGHTING.
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.
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.
Form of theatre where actors faces are covered with masks.
Early word for GOBO.
An overall control on a lighting control console. The Grand Master takes precedence over all other controls. See SUBMASTER.
Main level or gain control for a device, bus or mix on a sound control console.
An original (e.g. Master tape, master plan) which should be used only to make a copy from which to work.
A Department Head (e.g. Master Carpenter, Master Electrician).
See CHIEF ELECTRICIAN.
Sometimes Maximum Distance refers to the distance from the screen that a projector can focus the image. Most of the time, however, it is the manufacturer's opinion of how far from a screen the projector can be to cast an image that is useable (bright enough) in a fully darkened room. Generally this is very subjective. One projector might quote a distance that allows them to produce a 25ft diagonal image, while a brighter projector might quote a distance that only equates to a 20ft image. Beware!
MAXIMUM IMAGE SIZE
The largest image a projector can throw in a darkened room. This is usually limited by focal range of the optics.
Metal Halide discharge lamp. See also DISCHARGE LAMP.
Megabits per second. 1 Million bits per second.
Minature Circuit Breaker. Up to 63A (UK). See FUSE.
Moulded Case Circuit Breaker (over 63A - UK). See FUSE.
An electronic storage device which enables recording and subsequent "playback" of lighting states.
METAL HALIDE LAMP
The type of lamp used in many medium and all high-end portable projectors. These lamps typically have a "half-life" of 1000-2000 hours. That is they slowly lose intensity (brightness) as they are used, and at the "half-life" point, they are half as bright as when new. These lamps output a very "hot" temperature light, similar to mercury vapor lamps used in street lights. Their whites are "extremely" white (with slight bluish cast) and make Halogen lamp's whites look very yellowish by comparison.
A microphone is a transducer that changes acoustical energy (sound) into electrical energy.
The closest position that a projector can focus an image onto a screen.
The VDU associated with most medium and large lighting desks has a detailed mimic of the level of all dimmers and other associated information.
A lighting effect popular in discos, ballrooms etc. A large plastic ball covered with small mirror pieces. When a spotlight (usually a PINSPOT) is focused onto the ball, specks of light are thrown around the room. Usually motorised to rotate.
A device in sound reinforcement that has two or more signal inputs and a common signal output. Used to combine separate audio signals in desired proportions to produce an output audio signal.
Short for MOVING LIGHTS.
Another word for room resonance. When sound energy is restricted by boundaries (such as walls, floor, and ceiling) waves are developed at certain frequencies or wavelengths that are integers of the distance between the room boundaries. Room modes or resonances cause standing waves because once the wave is generated it stands there, i.e., the positive pressure peaks (anti-nodes) and negative pressure troughs (nodes) stay stationary within the boundaries.
A loudspeaker or system of loudspeakers that permits the performer to evaluate or monitor his sound alone or in conjunction with other sounds that may be desired and is mixed to the listeners preference by means of a separate monitor or reference mix.
A video display screen (not normally able to receive broadcast TV pictures) used with a CCTV system or a computer.
Monophonic Sound - Sound produced by a system in which one or more microphones feed a single signal to an amplifier(s) whose output is coupled to one or more loudspeakers.
Lighting effect. A large shallow circular box with calico cloth 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.
A zoom lens with the zoom in and out controlled by a motor usually adjusted from the projector's control panel and also the remote control.
See MOVING LIGHT.
Remotely controllable "intelligent" lighting instrument. Each instrument is capable of a massive variety of effects which are operated "live" via a moving light control desk, or can be pre-programmed by a standard memory lighting desk. The instruments require a power supply and a data cable (normally carrying DMX512 signal from the control desk). There are broadly two types:
Moving Head: A luminaire is mounted on a moving yoke.
Moving Mirror: A stationary luminaire directs light onto a motorized mirror.
Both types have in common:
A discharge (non-dimmable) light source
A dimming shutter
Motorized rotating colour wheels. Some offer colour mixing using graduated red, green and blue wheels or prisms.
Profile versions have motorized gobo wheels with rotation.
Strobing effects and adjustable iris. Some also have shutters.
The term "intelligent" is used as the instrument has a processor chip and electronics built into it, not because it's able to interpret the designer's artistic intent! It can be incredibly frustrating trying to get moving lights to behave exactly as required in a dramatic situation. Musicals and live music performances are more forgiving.
Moving Head lanterns are sometimes known as NODDING BUCKETS, Moving Mirrors are sometimes known as WIGGLIES or SCANNERS.
See MOVING LIGHT.
A 12 Volt lamp dichroic lamp commonly used in place of a Par 16 lamp in BIRDIES. See BIRDIE.
Material Safety Data Sheet. Form available from manufacturers of, for example, smoke fluids. Lists any hazardous ingredients and other safety-related data about the product.
(Medium Source Rare earth) High efficiency discharge lamp with a high colour temperature (approx 5600°K). Provides around 50% more light output than a incandescent lamp of the same wattage.
Short for 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. Sometimes known as a Multi or Snake.
Also called a Volt-Ohm-Meter (VOM). A measuring instrument that can measure different ranges of voltage, current, and resistance. A multimeter can have an analog needle indicator or a digital read out.
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 industry standard protocol (language/standard) for multiplexing is the digital USITT DMX512 (introduced in 1986, based on RS485 data protocol). 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).
RDM (Remote Device Management) is an emerging upgrade to DMX512 which will include bi-directional communication between controller and device.
DMX512-A (officially ANSI E1.11) is a new standard under development at ESTA which is backwards compatible with DMX512 but has stricter safety parameters and offers some upgrades of functionality.
A device allowing two or more signals to pass over and share a common transmission path simultaneously.
This is a power rating generally applied to high fidelity amplifiers for tones of short duration. It takes into account the fact that most amplifiers can produce a greater amount of power in short bursts than they can continuously. The rationale is that music is made up of such bursts rather than sustained single frequencies. It is higher than continuous power ratings for the same amplifiers. It is measured at a signal frequency of 1000 Hz for a specified distortion.