BNO Acoustics HD-70: In

Short For "in the circuit," in other words "active."

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.

BNO Speakers: Sound Source
Something that vibrates between 20 times a second and 20,000 times a second and therefore makes a sound pressure wave.

Power Supply
An electrical circuit which supplies voltage and current for devices to operate.

BNO Acoustics GT-60: Vacuum Tube
An amplifying device that is a tube.

Overtones
The harmonics of an instrument's sound minus the fundamental frequency.

BNO Acoustics XV-16: Voltage Controlled Oscillator
An oscillator that changes its frequency according to a control voltage fed to its control input.