Multiband Compression

Separate dynamics per frequency band, so the low end no longer pumps the whole mix.

Related

CompressorEqualizerDrum Kit

The question

Full-band compression lets every low hit pull the high end down with it. Multiband compression splits the spectrum so each range can follow its own dynamics.

How it works

A crossover divides the signal into two or more bands, often with Linkwitz-Riley filters that stay flat at the junction. Each band has its own threshold, ratio, attack and release, and the bands are summed again. Phase change around the crossover matters; linear-phase splitting avoids phase distortion but adds pre-ringing. Multiband compression is not multiband EQ, because it moves a gain envelope per band instead of drawing a fixed response.

Settings and what you hear

Use a slower attack and release on the low band to keep the kick punch. The mid band can control a surging vocal, and the high band can move faster. Crossovers often sit near 120 to 200 Hz and 3 to 5 kHz. Keep gain reduction around 2 to 4 dB per band; beyond that, a band sounds removed.

What to listen for

On a funk drum loop, solo the low band and hear whether kick and bass rise and fall together. Return to full range and notice whether the hats still pump with the kick. On voice and piano, hear whether compression near 3 kHz softens the consonants.

Common misconceptions

That multiband compression is multiband EQ; that more bands are always better; that splitting introduces no phase problems.

Sources

• Udo Zölzer, DAFX — Digital Audio Effects, dynamics and multiband sections — background checked, not quoted
• Giannoulis, Massberg and Reiss, Digital Dynamic Range Compressor Design, JAES 2012 — topology context checked, not quoted

Used for fact-checking only; all prose is original.