Brooks RM 909 reviews Contact Microphone

A device that senses vibrations and puts out an audio signal proportional to the vibrations.

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.

Brooks Hi Fi reviews Bass Roll Off
An electrical network built into some microphones to reduce the amount of output at bass frequencies when close-micing.

FOH (Front of House)
Refers to the speakers that face toward the audience. Also called the "main" speakers.

Brooks Hi Fi speakers Hz (Hertz)
1) An abbreviation for the term Hertz (the unit of frequency).
2) Unit of frequency equivalent to the number of cycles per second.

Feedback
1) The delayed signal sent back to the input of a delay line, used in repeat-echo effects.
2) The pickup of the signal out of a channel by its input or the howling sound that this produces.
3) In an amplifier, the phase reversed output signal sent back to its input, reducing gain but also distortion and noise.
4) This occurs when the sound coming out of the speakers goes back into the microphones, then back out the speakers, then back into the mics…and so on. This can build very quickly to a point where everyone in the room is holding their ears and screaming at you. It can also cause damage to the PA.

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

LFO
Low-Frequency Oscillator (an oscillator that puts out an AC signal between .1 Hz and 10Hz used for a control signal).