3. Parallel compression
How to add density without losing attack: why it works, how to build it in Studio One and which instruments it's useful on beyond the drums.
A normal compressor lowers the loudest parts, and that takes some punch from the signal. Parallel compression does something else: it leaves the original signal intact and blends in underneath a heavily compressed copy. The soft parts rise and the attack stays where it was.
How it’s built
- Create an effects channel and add a compressor.
- Add a send from the track or bus. Keep the effects channel’s fader down.
- Set the compressor while listening to the channel alone: it should sound exaggerated.
- Go back to the mix and raise the fader from zero.
Starting settings
Parallel channel
Try what the compressor does to it
Lower the threshold to 10 dB or more of reduction and listen: the soft parts rise and the hit gets crushed. That version, alone, sounds bad. It’s the one you’ll blend underneath.
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).
- •🎸 Bass — a synthesized riff with dynamics: ideal for hearing compression.
- •📢 Pink noise — an even sound across the whole spectrum: ideal for “seeing” the EQ.
- •🎵 Load your audio — your own file (MP3, WAV, OGG, FLAC, M4A…); it's processed locally in your browser and isn't uploaded anywhere.
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”.
Where it’s useful
- Drums: the classic use. It gives the kit size without crushing the kick and snare. It has its own section.
- Bass: adds presence and helps soft notes be heard.
- Vocal: a compressed copy, blended low, helps it not get lost without crushing the lead. Very carefully: it also raises breaths and room.
- Distorted guitars: almost never. They already come heavily compressed and have no dynamics to recover.
It's a tool for adding size, not for fixing problems. If the balance and regular compression don't work, this won't solve it. You can finish a whole mix without using it.
How far to raise it
Raise the fader until you notice the instrument growing and lower it a little. Then bypass it: if it feels smaller without it, but with it on you don’t hear “an effect”, it’s right.
Phase
If the copy arrives late relative to the original, you can lose punch or lows. Studio One compensates plugin latency automatically. If the instrument thins out when you raise the parallel, check the polarity and that there’s no odd plugin in that path.
Common mistakes
What NOT to chase yet
Quick path: parallel
Quick path
- Effects channel with a compressor, fader down.
- Send from the drum bus.
- Ratio 8:1 or more, fast attack, 10 dB or more of reduction.
- High-pass near 100 Hz.
- Raise the fader from zero until it grows.
- Lower it a little and compare at the same volume.
Expected result
Expected result
A bigger, denser instrument that keeps its punch. Removing the parallel makes you feel the drop, but with it on you don’t hear an effect. Another way to enlarge the mix, without adding level, is space.