Shape the tone of a track, band by band

How an equalizer works

What the bands actually control

Every sound is a stack of frequencies, and an equalizer turns parts of that stack up or down. Roughly: 32-125Hz is the weight you feel more than hear, the kick drum and the bass guitar. 250-500Hz is the body of most instruments, and also where recordings most often sound muddy. 1-4kHz is where speech and vocals live, which is why a small boost there makes words clearer. 8-16kHz is air and cymbal shimmer.

Cut before you boost

Boosting adds level, and enough boosting will push the signal past full scale and clip it — the harsh crackle you sometimes hear after someone maximises the bass. The professional habit is the opposite: if the vocal is buried, try cutting the frequencies around it rather than boosting the vocal itself. You end up with the same balance and more headroom.

If you do boost, drop the overall volume by a similar amount afterwards.

Small moves, wide bands

Two or three decibels is a real change. Anything beyond about six starts to sound processed rather than corrected, and a very narrow boost tends to ring. Broad, gentle curves are what make a recording sound better without sounding edited.

What an equalizer cannot do

It can only shape what is already in the file. If a recording was made without any real bass, boosting 60Hz raises the noise floor and nothing else. The same goes for high frequencies removed by heavy MP3 compression — those bands are empty, and turning up an empty band gives you hiss. Start from the best source file you have.