3. Compression: a bass that doesn't move
How to compress bass so every note weighs the same without losing attack: threshold, ratio, attack, release, and why two gentle compressors beat one hard one.
Bass is the instrument that benefits the most from compression. Its job in the song is to hold a constant floor, and for that every note has to weigh the same: if one note of the riff jumps and the next one sinks, the whole song wobbles. Compression is what turns a human take into that even floor.
The four controls, applied to bass
Sets the level at which compression starts. On bass more compression is tolerated (and wanted) than on any other instrument: 3–6 dB is normal, not excessive. What you don't want is it compressing flat out ALL the time: the meter has to move with the music.
How hard it compresses past the threshold. 2:1 is gentle and transparent; 4:1 is the bass standard; 8:1 or more starts to sound like 'bass glued to the floor', useful in very dense metal but at the cost of expression.
The control that changes the character the most. Slow (20–30 ms) lets the pick 'click' through before compressing: the bass keeps attack and definition. Fast (1–5 ms) catches the attack too: the bass turns rounder and softer, and loses bite. In rock/metal you almost always want a slow attack.
How long it takes to stop compressing. Too long and the compressor stays clamped, so the bass loses pulse. Too short and it 'pumps' audibly with every note. Set it by ear: the bass has to breathe with the song's tempo, not against it.
Two gentle compressors instead of one hard one
If you need a lot of levelling (a fingerstyle take, or a riff that runs the whole neck), compressing twice a little sounds much better than once a lot.
The serial chain
- Compressor 1: low ratio (2:1), slow attack, 2–3 dB of reduction. Levels generally and transparently.
- Compressor 2: higher ratio (4:1 or 8:1), slightly faster attack, another 2–3 dB only on the peaks that still stick out.
The result is 5–6 dB of control that doesn’t sound like compression, because no plugin is working at its limit.
Try it with the gain reduction meter
Pick the bass source (the synthesized riff has dynamics on purpose) and run the full experiment: lower the threshold until you see 3–6 dB on the gain reduction meter, then move between fast and slow attack while listening to what happens to the pick “click”. It’s the most direct way to understand why a slow attack is the norm on bass.
Playground · Compressor
- •▶ Play — plays the audio in a loop.
- •No compression / With compression — switch between the sound with and without compression to compare, at the same volume. The segment with the lit border is the one you're hearing (“A/B” comparison).
🎧 Audio to processChoose which sound goes through the effect:
See how the output line (orange) stays more even than the input line (gray): the compressor brings loud and soft closer together. The more you compress, the flatter it gets.
The compressor evens out the volume (it lowers the loudest parts). Move each control and watch the GR bar above:
A recipe to hear it clearly: source 🎸 Bass, ratio 4:1, and lower the threshold until you see 3–6 dB on the GR bar. Turning the compression on and off you'll notice the bass gets more even and “glued”.
Without a levelled bass you can't make any balance decision: the fader that works for one note doesn't work for the next. Best solved early, even if the fine tuning gets revisited at the end.
Before compressing: clip gain
If the problem is two or three isolated notes jumping out, don’t solve it with the compressor: pull those notes down with clip gain (the audio’s level, before the plugins). The compressor is then free to do its musical job instead of fighting three isolated peaks, and the bass sounds more natural.
Common mistakes
What you should NOT chase yet
Quick route — levelling the bass
Quick path
- Use clip gain to pull down the two or three notes that jump in level.
- Compressor after the EQ: ratio 4:1, attack 10–30 ms, release ~150 ms.
- Lower the threshold until you get 3–6 dB of reduction on the loud notes.
- Match the output volume and compare against bypass: it should sound more even, not louder.
- If you need more control, add a second gentle compressor instead of squeezing the first.
Expected result
Expected result
An even bass with punch: every note of the riff weighs the same, the gain reduction meter moves with the music (3–6 dB on peaks) and the pick attack is still there. Listening to the song, the bass should feel like a stable floor rather than something rising and falling. With the level sorted, next comes the section that decides whether the bass exists outside your studio: saturation.