The musical interpretation of an audio frequency.

A random signal with a power spectral density which is inversely proportional to the frequency. Each octave carries an equal amount of noise power. Pink noise sounds natural, and resembles the sound of a waterfall. (cf. White Noise)

The part of a guitar that converts the string vibrations to electrical signals. Also the stylus/cartridge assembly used to replay vinyl records.

An audio connector developed by RCA and used extensively on hi-fi and semi-pro, unbalanced audio equipment. Also used for the electrical form of S/PDIF digital signals, and occasionally for video signals.

An effect which combines a signal with a phase-shifted version of itself to produce creative comb-filtering effects. Most phasers are controlled by means of an LFO.

The relative position of a point within a cyclical signal, expressed in degrees where 360 degrees corresponds to one full cycle. (Also see Polarity)

Pre-Fade Listen. A system used within a mixing console to allow the operator to audition a selected channel signal, prior to the fader, and thus independent of the fader setting. Normally used to check the level of the signal through the channel to optimise the gain structure, or to confirm the presence of a signal before fading it up. (See AFL and Solo)

The practice of removing all headroom to maximise the peak level of an audio signal on a particular medium. So all peak-normalised material will have the same maximum peak value, but the perceived loudness is likely to vary between different tracks. The technique became popular and commonplace with the advent of digital formats such as CD, where the signal level was typically engineered to reach 0dBFS. (See also Loudness-Normalisation, Mastering and Loudness Wars)

The maximum instantaneous level of a signal.

Pulse Code Modulation - the technique used by most digital audio systems to encode audio as binary data.