A system used within mixing consoles to allow specific signals to be monitored at the level set by their fader, typically after the pan-pot for channel AFL. Aux sends, matrix outputs and so forth are generally monitored AFL rather than Pre Fade Listen (see PFL and Solo).

An AES standard which defines the connectivity, powering, remote control and audio format of ‘digital microphones’. The audio information is conveyed as AES3 data, while a bespoke 10V phantom power supply conveys remote control and clocking information through an ingenious modulation technique.

An AES standard that defines a method of evaluating the dynamic range performance of analogue-to-digital (A-D) and digital-to-analogue (D-A) converters.

An AES standard that defines the use of a specific form of AES3 signal purely for clocking purposes. Also known as DARS (Digital Audio Reference Signal).

An AES standard which defines the serial MADI interface (Multichannel Audio Digital Interface). MADi can convey either 56 or 64 channels via single coaxial or optical connections at base sample rates. A double-rate format with half the channel count is also available.

Acronym for Alesis Digital Audio Tape, referring to the company's popular range of digital eight-track tape machines released in the early 1990s. Now more commonly used as a shorthand term for the ADAT Lightpipe digital connection format.

A digital audio interface which passes two digital audio channels, plus embedded clocking, control and status data, with up to 24 bits per audio sample and supporting sample rates up to 384kHz.

Buffer — An electronic circuit designed to isolate the output of a source device from loading effects due to the input impedance of destination devices.

A system used to verify that a MIDI connection is working. It involves the sending device sending frequent short messages to the receiving device to reassure it that all is well. If these active sensing messages stop for any reason, then the receiving device will recognise a fault condition and switch off all notes. Not all MIDI devices support active sensing.

When creating artificial waveforms in a synthesizer, changes in the signal amplitude (or frequency) over time are controlled by an ‘envelope generator’ which typically has controls to adjust the Attack, Decay, Sustain and Release times, triggered by the pressing and subsequent release of a key on the keyboard.