Brooks RM 909 Bar

A term meaning the same thing as the term Measure (the grouping of a number of beats in music, most-often four beats).

A/D
An abbreviation of Analog to Digital Conversion (the conversion of a quantity that has continuous changes into numbers that approximate those changes), or Analog to Digital Converter.

Brooks HI FI projectors Level
Sets output volume of individual PA input channels. Usually positioned as sliders at the bottom of the soundboard.

CD (Compact Disc) :
1) Digital sound storage medium. Provides a high quality source of music, sound effects etc. Also used as a playback medium for sound effects etc. by large theatres with long running shows, although CDR (Recordable CD) is becoming more affordable by the day.
2) An abbreviation of the term Compact Disc (a small optical disk with digital audio recorded on it).

Brooks Hi Fi speakers Electret Mic
A condenser microphone where the capacitor plates are given a charge during manufacture which they retain, therefore requiring no external power supply.

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

File
A collection of digital data stored in a computer's memory bank or on a floppy disc.

Ground
In electronics, a place (terminal) that has zero volts.