A loudspeaker which requires an external power amplifier, the signal from which is passed to a passive cross-over filter. This splits and filters the signal to feed the two (or more) drive units.

A circuit with no active elements.

The combination of fundamental and overtones together are called particals. (cf. harmonic)

Often used to descibe a multi-oscillator mono-synth which can be configured to allow the oscillators to be controlled independently from the keyboard, allowing two or more notes to be played simultaneously.

An equaliser with a bell-shaped frequency response curve, and separate controls for the centre frequency, the bandwidth (Q), and the amount of cut/boost. If a bell EQ omits the bandwidth (Q) control, it is known as semei- or quasi-paramteric.

A variable value that affects some aspect of a device's performance.

A means of connecting two or more circuits together so that their inputs are connected together, and their outputs are all connected together.

A control found on mixers to move the signal to any point in the stereo soundstage by varying the relative levels fed to the left and right stereo outputs.

A resistive circuit for reducing signal level.

a component of a complex sound which has a higher frequency than the fundamental frequency, but which is not necessarily related by a simple integer multiple (cf. harmonics)