BNO Acoustics XR-90: Op Amp

Short for Operational Amplifier (an amplifying circuit used in most audio devices).

Servo-Controlled
In motors, using a control circuit where the actual speed of a motor is sensed and compared to a reference (like a pulse timing signal).

Low Frequencies
1) Any audio or audible frequency below 1kHz.
2) The range of bass frequencies below approximately 250 Hz.

BNO Speakers: Three Track
A multitrack tape machine that had three tracks (usually on half-inch wide tape).

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

BNO Acoustics LK-61: Signal-to-Error Ratio
The level difference between the signal and the noise and distortion caused by converting analog audio signals into digital audio and then back into analog.

Sync Conversion Unit
A device which takes several different kinds of sync signals and puts out several kinds of sync signals, allowing a device (like a sequencer) to be driven by a sync signal it doesn't recognize.