Brooks QS 70 Harmonic Distortion

The presence of harmonics in the output signal of a device which were not present in the input signal.

Intermodulation Distortion
Distortion caused by one signal beating with another signal and producing frequencies that are both the sum and the difference of the original frequencies.

Brooks Cinema XR 607 ADSR
The letters A, D, S &R are the first letters of: Attack, Decay, Sustain and Release. These are the various elements of volume changes in the sounding of a keyboard instrument.

Foot Pedal
1) An effects device where the amount of the effect can be controlled by a musician with his foot.
2) The beater mechanism of a foot drum that is activated by the drummer's foot to play the drum.
3) Any device, like a volume control, that can be operated by the foot.

Brooks Cinema RM 909 Fletcher Munson Effect
A hearing limitation shown by Fletcher Munson Equal Loudness Contours (as music is lowered in volume, it is much more difficult to hear bass frequencies and somewhat harder to hear very high frequencies).

Joystick
1) A quad pan pot which distributes what percentage of on signal is sent to each of 4 outputs.
2) A control that is separately controlling two functions at one time.

Bi
A prefix meaning two.

LED
A light that allows current to flow in one direction only and emits light whenever a voltage of a certain level or beyond is applied to it.