What does OTT do? Multiband upward and downward compression, explained

OTT ("over the top") is multiband compression in both directions. It splits the sound into three bands, lows, mids and highs, then squashes the loud parts down and lifts the quiet parts up in each band at the same time. Details that were buried come forward, peaks get tamed, and the sound gets thick, bright and in your face. That's why producers put it on synths, 808s, drums and vocals.

How to do it

1. Put an OTT-style plugin on a synth, an 808 or a drum bus.
2. Start around 30 to 50% depth. 100% is a special effect, not a starting point.
3. If it gets hissy or roomy, turn down the upward part: that's the quiet noise being lifted.
4. On drums, use a slower time setting so the hits keep their punch.
5. Compare at the same volume. OTT makes things louder, and louder always sounds better at first.

Why it works

Each band gets its own compression, so a loud kick doesn't push the hats down, and the upward part brings out detail a normal compressor would leave quiet. The result has far less dynamic range in every band, which reads as dense and exciting on small speakers.