Brooks Speakers Automatic Gain Control (Automatic Volume Control)

A compressor with a very long release time used to keep the volume of the audio very constant.

Expansion
The opposite of compression; for example, an expander may allow the signal to increase 2 dB every time the signal input increased by 1 dB.

Brooks TM-22 Comb Filter
1) The frequency response achieved by mixing a direct signal with a delayed signal of equal strength especially at short delays.
2) Loosely used to also describe effects that can be achieved with comb filtering as part of the processing.

Inverse Square Law
Simply stated, the fact that in an un-obstructed area (like an open field) the sound pressure level will drop to half-pressure (-6 dB) every time the distance to the sound source is doubled.

Brooks GT 44 Key
The control of a dynamics processing device by an external audio signal.

Jack Bay
A series of jacks which have connections for most of the inputs and outputs of the equipment in the control room.

Delay (Digital, Analogue)
1) Effect used to create echo…echo…echo…echo…echo…
2) In more advanced systems used in very large venues, delay can be used to time the arrival of the signal to the speakers in the back of the room so that people in the back hear the sound coming from those speakers at the same time that the sound coming from the speakers in the front of the room arrives.

Harmonics
Integer multiples of a fundamental frequency, the fundamental itself being the first harmonic, its first overtone the second harmonic, etc. Attributing to instruments, voices, etc. their distinctive timbre.