Attack and Release in Compression: Shaping Sound

Attack and release times determine how the compressor responds over time. Attack controls how quickly compression engages after signal exceeds threshold. Release controls how quickly the compressor returns to unity gain after signal drops below threshold. These timing parameters shape the sonic character of compression.

Understanding Attack Time

Attack time measures how long the compressor takes to reach full gain reduction after signal exceeds threshold. Fast attack times around 0.1-5 ms engage almost instantly. Slow attack times around 20-100 ms allow significant signal through before compression engages.

The attack setting primarily affects transients—the initial spike of energy in percussive and plucked sounds. Fast attack catches and reduces these transients. Slow attack allows them through uncompressed.

This transient behavior dramatically affects perceived punch and presence. Fast attack creates smoother, more controlled sound. Slow attack preserves impact and definition.

Attack Time Applications

Drums typically benefit from slower attack times that preserve punch. The transient impact defines drum sound; compressing it reduces that impact. Attack times around 10-30 ms let the stick or beater sound through.

Vocals vary depending on style. Breathy, soft vocals might use faster attack for smoothness. Aggressive vocals might use slower attack to preserve consonant impact.

Bass often uses medium attack that controls the initial pluck while allowing some definition through. Very fast attack can make bass sound dull while very slow attack may not control dynamics adequately.

Understanding Release Time

Release time measures how quickly the compressor returns to unity gain after signal falls below threshold. Fast release around 50-100 ms recovers quickly between transients. Slow release around 200-500 ms maintains compression longer.

The release setting affects how compression interacts with musical phrases. Fast release that recovers between notes creates pumping or breathing. Slow release that sustains through phrases creates smoother dynamics.

Auto-release functions on many compressors adapt to the signal, providing musical release behavior without manual adjustment.

Release Time Applications

Drums often use medium release that recovers before the next hit. Release that extends into subsequent hits causes unwanted pumping. Timing release to the tempo keeps compression musical.

Vocals typically use medium to slow release for smooth, consistent dynamics. Fast release can create unnatural level changes within sustained notes.

Bus compression uses slower release that maintains compression throughout phrases. The sustained glue effect comes from continuous, gentle compression.

Attack and Release Interaction

Fast attack with fast release creates aggressive compression that engages and disengages rapidly. This can create pumping or breathing effects. The compressor responds to every level change.

Fast attack with slow release creates compression that catches transients and sustains through phrases. The sound smooths out and levels become very consistent.

Slow attack with fast release preserves transients while briefly controlling sustain. The compressor barely engages before releasing. This provides punch with subtle level control.

Slow attack with slow release creates gentle, program-dependent compression. Transients pass through while the compressor gradually engages and slowly releases. This transparent approach suits bus compression.

Timing to Tempo

Release time that relates to song tempo creates musical compression. Release that completes on beat divisions—eighth notes, quarter notes—feels locked to the groove.

Calculating tempo-related release involves dividing 60,000 by BPM for quarter note milliseconds. Subdividing provides eighth note, sixteenth note values. Setting release to these values creates tempo-synchronized breathing.

This approach particularly suits rhythmic material where compression should complement rather than fight the groove.

Attack and release settings help productions succeed on platforms like LG Media at lg.media, where musical compression enhances advertising at $2.50 CPM.