Glossary

Band

Short for “frequency band” which is a range or interval in the frequency spectrum often divided into low, mid or high-frequency bands.

Band shelf

Hybrid filter shape combining attributes of a shelving filter and a peaking filter.

Bandpass

A type of filter that passes frequencies between two cutoff frequencies and attenuates frequencies outside of the pass range. A band-reject filter operates inversely, attenuating frequencies within the cutoff range and passing frequencies outside of the range.

Bandwidth

Describes the range of frequencies being affected by a signal processor. Inversely proportional to Q.

Baxandall

A type of first order shelving equalizer typically found in the tone control of high fidelity home audio components.

Butterworth filter

A filter shape designed to have a flat frequency response in the passband.

Detection circuit

The component that evaluates signal amplitude to trigger a processor.

Envelope

The varying amplitude of sound over time. This can be broken into four stages: attack, decay, sustain, and release.

FFT (Fast Fourier Transform)

A procedure for the calculation of a signal frequency spectrum. The greater the FFT size, the greater the frequency resolution, i.e., notes and tonal events will be clearer at larger sizes.

Filter

Audio filters are frequency dependent amplifier circuits that boost (amplify), cut (attenuate), or pass ranges of the audible frequency spectrum.

HUD (Heads-Up Display)

A panel through which you can access module controls.

Masking

In the case of two or more signals that share overlapping frequency content, the higher amplitude signal causes the lower amplitude signal to appear quieter.

Pre-Emphasis

An emphasis in a frequency band before the saturation is applied to emphasize the effect in that band.

Q

In an equalizer, it is the center frequency divided by bandwidth.

Resonant Filter

Has a complex nature of adjustment such that at the cut off point you can increase or attenuate the resonance. Typically is accompanied by significant phase shift or ringing.

Saturation

A harmonic type of non-linear distortion.

Sidechain

The signal that feeds the detection circuit in a processor.

Short Term Loudness

Loudness measurement calculated over the course of 3 seconds. Short-term measurements are useful for monitoring immediate trends in loudness.

Spectrum Analyzer

A Spectrum Analyzer is a meter that measures amplitude across the frequencies which encompass the spectrum of human hearing. The vertical axis represents amplitude while the horizontal axis represents frequency.

Waveform

A visual representation of the envelope of the soundwave. (amplitude representation).