Nothing frustrates viewers more than losing your commentary under a wall of game explosions and music. Audio ducking fixes this automatically: the moment you start talking, your game and music volume dips so your voice stays clearly on top, then rises back up when you pause. Here is how the technique works and how to set it up in OBS so your voice is always intelligible.
What ducking is
Ducking is automatic, dynamic volume control driven by one source listening to another. Your voice acts as the trigger: when the mic detects you speaking, it tells the game and music channels to duck — drop by a set amount of decibels — so your commentary cuts through. When you stop, those channels return to full volume. It is the same technique radio DJs use to talk over music, applied to your stream.
The tool: a sidechain compressor
Ducking in OBS is done with a Compressor filter set to “sidechain” mode. You place the compressor on the source you want to duck — your game or desktop audio — and set its sidechain/ducking source to your microphone. The compressor then reduces the game volume whenever your mic signal crosses a threshold. It is the exact same compressor used for voice, just triggered by a different input.
| Setting | Starting value | What it does |
|---|---|---|
| Ratio | 4:1 to 10:1 | How hard the game ducks |
| Threshold | -30 to -40 dB | How loud your voice must be to trigger |
| Attack | ~5 ms | How fast the game dips |
| Release | ~150–300 ms | How fast the game recovers |
| Sidechain source | Your mic | The trigger input |
Step by step in OBS
Right-click your Desktop Audio (or game) source, choose Filters, and add a Compressor. In the compressor’s settings, find the “Sidechain/Ducking Source” dropdown and select your microphone. Set the ratio around 4:1 to start, threshold near -35 dB, a fast attack of a few milliseconds, and a release of roughly 200 ms. Now talk into your mic and watch the game audio dip automatically as you speak.
Dialling it in
Test with real gameplay and real commentary. If the game does not duck enough to hear you, raise the ratio or lower the threshold so your voice triggers it more easily. If the ducking is too aggressive and the game vanishes distractingly, reduce the ratio. Tune the release so the game rises smoothly during your pauses rather than pumping up and down between every word — a release around 200–300 ms usually feels natural.
Common pitfalls
Two things trip people up. First, if the threshold is too low, background noise or breaths can trigger ducking, making the game flutter; pair ducking with a noise gate on your mic to prevent false triggers. Second, an overly short release causes obvious pumping; lengthen it until the recovery sounds smooth. The aim is ducking so transparent that viewers only notice they can always hear you.
Frequently asked questions
Does ducking replace manually balancing my audio levels?
It complements it. You still set sensible base levels for your mic and game, but ducking dynamically lowers the game only while you speak, giving your voice priority without permanently burying the game. Set good static levels first, then add ducking for the automatic dip during commentary.
Why does my game audio flutter or pump with ducking on?
Usually the release is too short or the threshold is too low. Lengthen the release to around 200–300 ms so the game recovers smoothly, and raise the threshold so only your actual voice triggers ducking. Adding a noise gate to your mic also stops breaths and background noise from causing false dips.
Bottom line
Audio ducking keeps your commentary on top by automatically dipping game and music volume whenever you speak, using a sidechain compressor in OBS set to trigger from your mic. Start around 4:1 ratio, a -35 dB threshold, fast attack, and a 200 ms release, then fine-tune until the effect is invisible. Pair it with a noise gate and your voice will cut through every explosion cleanly.
