Tutorials Audio

Mixing Music Under Dialogue: Ducking and Sidechain Compression

Intermediate · ~25 min

Overview

Background music fighting with dialogue for space is the single most common mix problem in podcast and video production. Sidechain compression, automatically lowering the music's volume whenever dialogue is present, is the professional solution, and it's available in every major DAW for free.

What You Need

A DAW with sidechain-capable compression (all major DAWs support this)
Separate dialogue and music tracks

Steps

Route dialogue as your sidechain trigger

Sidechain compression uses one track's signal (dialogue) to control processing on a different track (music). Confirm your DAW's routing so the dialogue track can act as an external trigger, usually via a send or a sidechain input selector on the compressor.

Add a compressor to your music track

Insert a compressor (most DAWs' stock compressor supports sidechain input) on the music track. This is the track that will actually get quieter.

Set the sidechain input

In the compressor's sidechain/external input settings, select your dialogue track (or its send bus) as the trigger source. The compressor will now react to dialogue level, not the music's own level.

Dial in threshold, ratio, attack, and release

Set the threshold so it only triggers on actual speech, ratio around 4:1-8:1, a fast attack (1-10ms) so the duck starts immediately with speech, and a release around 200-400ms so the music doesn't pump obviously back up between words.

Automate manually where sidechaining overreacts

For a handful of moments where automatic ducking sounds unnatural (a musical swell you want to protect, a brief pause you don't want the music jumping back up during), draw manual volume automation over the sidechained result.

Pro Tips

A release time that's too fast causes audible "pumping" (the music visibly breathing with every word). Too slow and the music stays ducked through short pauses. Start around 250ms and adjust by ear.
Duck by 6-10 dB as a starting point for most podcast/video mixes, enough to clear space for dialogue without music disappearing entirely.
If your DAW doesn't support sidechaining well, manual volume automation on the music track achieves the same result with more manual effort but total control.

Knowledge Base

Why Ducking Beats a Static Volume Reduction

Simply lowering music volume for an entire segment either leaves it too loud during dialogue or too quiet during instrumental moments. There's no single static level that works for both. Sidechain ducking responds dynamically, staying appropriately loud when there's no dialogue and automatically dropping the instant speech begins.

How Sidechain Compression Actually Works

A normal compressor reduces a track's own level based on its own signal. A sidechained compressor reduces one track's level based on a different track's signal entirely. The music compressor "listens" to the dialogue track and reacts to it, rather than to the music itself.

Getting a Natural-Sounding Duck

The difference between an obvious, distracting duck and an invisible one is almost entirely attack and release timing. Too fast a release creates audible pumping. Too slow leaves music oddly quiet during pauses. Small adjustments here matter more than the exact threshold or ratio values.

Where This Fits

This guide covers one specific part of mixing and colour. The wider picture. The full mix workflow from gain staging and balance through bus processing and knowing when to stop, is in Mixing a Full Song: From Rough Levels to Final Bounce, which frames the discipline as a whole and links out to the detailed guides underneath it, including this one. If you are starting from scratch rather than solving a specific problem, read that first and come back here.

FAQ

Q: Do I need a paid plugin for sidechain compression?
A: No. Every major DAW's stock compressor (Logic, Ableton, Pro Tools, Premiere's Essential Sound panel, REAPER's ReaComp) supports sidechain input at no extra cost.

Q: Should I sidechain sound effects too, not just music?
A: Often yes for continuous ambient beds (traffic, room tone) that would otherwise compete with dialogue the same way music does, short, punchy sound effects usually don't need it.