Compressor/Limiters – Basic Recording Equipment

Vocabulary flashcards covering key terms, components, models, and concepts related to compressors and limiters as discussed in the lecture notes.

Compressor/Limiter

A device inserted into a microphone or signal chain to control dynamics by automatically reducing gain above a set threshold.

Threshold

The signal level at which gain reduction starts; below this level no compression occurs.

Attack Time

How quickly a compressor reduces gain after the signal exceeds the threshold; fast attack controls transients, slow attack lets transients pass.

Release Time

How quickly a compressor returns gain to normal after the signal falls below the threshold.

Compression Ratio

The amount of gain reduction applied to signals above the threshold (e.g., 2:1, 4:1, 8:1); 10:1 or higher is considered limiting.

Side-Chain Input

An external input that feeds the compressor’s detector circuit, allowing the compression to be initiated by an source outside the original signal, such as a kick drum “pumping” a keyboard pad.

LA-2A

The classic example of an optical compressor. It uses a light source and photocell for gain control, giving slower, smooth attack / release characteristics

FET Compressor

Employs a field-effect transistor for gain control, resulting in very fast response times as short as 20 micro seconds (.02 miliseconds)(e.g., UREI 1176).

VCA Compressor

Uses a voltage-controlled amplifier; offers fast response and extensive parameter control (e.g., dbx 160 series).

Limiter

A type of compressor set to a high ratio (≥10:1) with fast attack, acting as a brick-wall to prevent levels from exceeding a set maximum.

Pumping/Breathing

Audible volume swings caused by overly fast release times in compression.

Teletronix LA-2A

Classic tube optical compressor/limiter with simple controls and airy vocal sound; famous for its gray or silver faceplates.

UREI 1176

Iconic FET limiting amplifier with fast attack/release, multiple ratio buttons, and numerous sought-after vintage revisions.

Brick-Wall Limiting

Limiter behavior that stops audio from exceeding a threshold. Essentially compression with a ratio of infinty:1

Gain Reduction

The amount (in dB) by which a compressor or limiter lowers signal level when active.

Dynamics

The overarching term for any kind of compression, expansion, gating, or limiting. These processors control the available dynamic for audio.

De-Esser

A compressor combined with sidechain EQ to take out sibilance from vocals.

Multiband Compressor

A type of compressor that has independent parameters for different frequency ranges. This allows compression of only certain frequencies like sibilance, proximity effect, or boominess without affecting the entire signal.