DaVinci Resolve Audio Ducking: Ducker, AI & Sidechain

Quick answer: Put dialogue and music on separate tracks, select the music track, enable its Ducker Track FX and choose the dialogue track as the source. Set a modest Duck Level, then tune Rise Time, Hold and Recovery until the music moves without obvious pumping. Use Fairlight compressor sidechain when the source or target is a bus, and use manual keyframes for exceptions the automatic detector can't understand.

Audio ducking has one job: clear space for the words while keeping the music emotionally present. The technical setup takes minutes. The difficult part is making the movement quiet enough that viewers hear the dialogue, not the mixer working.

DaVinci Resolve 21 offers three routes that are often described as the same feature. Ducker Track FX is the fastest direct method. Fairlight sidechain compression provides routing and compressor control for tracks or busses. Studio's AI Audio Assistant can apply ducking during a much broader automatic mix. Choose deliberately instead of stacking all three.

Pick the Right Ducking Method

Ducker Track FX is available in the free version as well as Studio. Blackmagic's latest Fairlight Audio Post guide explicitly shows it among the free edition's Track FX. AI Audio Assistant is different and is labeled Studio-only.

Prepare Dialogue and Music Before Ducking

Automation can't fix a timeline whose categories are mixed together. Keep dialogue on dialogue tracks and music on music tracks. Do not place a voiceover clip between music clips on the same track and expect a track-level Ducker to understand the editorial meaning.

1. Move speech to clearly named tracks such as Dialogue or VO.
2. Keep the bed on a separate Music track.
3. Set a sensible static balance first. The music should already be close to its non-dialogue level.
4. Clean obvious bumps, clothing noise and long empty regions from the dialogue source.
5. Listen once without ducking and mark the places where the voice is actually masked.

Ducking reacts to signal level, not meaning. A breath, mic bump or loud room tone can trigger it just like a word. Basic clip cleanup from the mute and split audio workflow often prevents more false triggers than another round of control tweaking.

Set Up Ducker Track FX

1. Open the Edit or Fairlight page and expose the audio mixer.
2. Select the music track. This is the target whose level will be reduced.
3. Open Track FX from the track's Inspector or mixer channel and enable Ducker.
4. In Source, choose the dialogue or voiceover track that should trigger the reduction.
5. Add more dialogue sources with the plus control when several speakers live on separate tracks.
6. Loop a section containing speech, silence and another speech phrase while you tune the controls.

Put the Ducker on the music, not the voice. The source is only the detector. The target is the signal that changes. This source-versus-target reversal is the most common setup mistake.

Blackmagic's Fairlight overview describes the same flow: open Ducker on the target track, choose one or more dialogue sources, then adjust the amount and recovery. Resolve 19.1 added multiple source tracks, so separate lav, boom and voiceover tracks can all control the same music bed.

Understand the Ducker Controls

• Duck Level: how far the target track is reduced while the source is active.
• Lookahead: lets reduction begin before the detected speech reaches the output, preventing the first syllable from fighting the music.
• Rise Time: how the Ducker moves into the reduced state.
• Hold: how long it stays reduced through a short pause.
• Recovery: how it returns toward the original music level after speech.

Start with depth, then timing. Lower Duck Level until the words are clear, but stop before the music appears to fall through a trapdoor. Next, tune the entrance around the first syllable. Finally, set Hold and Recovery so brief pauses inside a sentence do not make the music breathe between every few words.

There's no universal dB preset. A sparse piano bed, dense rock track, quiet narrator and energetic presenter mask one another differently. Blackmagic training exercises use example values to teach the controls; they aren't delivery standards. Use the actual program and monitor at a realistic playback level.

Use Fairlight Sidechain Compression for Tracks or Busses

The Ducker is a Track FX. If several dialogue tracks already feed a dialogue bus and several music stems feed a music bus, sidechain the busses instead of repeating the same Track FX across every stem. The Fairlight bus routing guide explains the bus structure before you build the detector path.

1. Route dialogue tracks to a dialogue bus and music tracks to a music bus using the Fairlight bus assignments.
2. Open Dynamics on the music bus.
3. Enable the Compressor.
4. In the compressor's Sidechain area, switch sidechain On.
5. Choose the dialogue bus as the sidechain source.
6. Use Listen briefly to confirm the detector hears the intended dialogue bus, then turn Listen off.
7. Set Threshold and Ratio for gain reduction; shape the move with Attack, Hold and Release.

Threshold determines when the detector causes compression. Ratio controls how strongly the music is reduced after that threshold is crossed. Attack controls entry; Hold keeps the reduction steady; Release controls the return. The Fairlight compressor guide explains the same controls in a dialogue context. Watch the gain-reduction meter, but decide with your ears.

A sidechain isn't an audible cable from dialogue into music. The dialogue bus remains in the normal mix. A detector feed measures it and controls the compressor on the music bus. If Listen remains enabled, you may hear only the detector and think the routing failed.

Where AI Audio Assistant Fits

AI Audio Assistant is a whole-mix starting point in Resolve Studio, not simply a newer Ducker button. Blackmagic's Resolve 20 New Features Guide says it can organize and color tracks, even dialogue levels, adjust mixer faders, clean dialogue, apply music ducking, write automation and add mastering processing for a chosen delivery standard.

Use it only after separating audio elements by track and assigning correct track categories. Run it on an unmixed duplicate timeline, play the entire result, inspect written automation and compare it with the untouched version. If all you need is one music bed under one voiceover, Ducker is faster and more transparent.

Don't run Audio Assistant, Ducker and a bus sidechain blindly on the same music path. Their reductions can add together and make the bed collapse. Bypass routes one at a time and keep the system whose result is easiest to control.

Use Keyframes for Editorial Exceptions

Automatic detection can't know that a musical hit should stay loud under a quiet line, or that the music needs to rise before the speaker finishes. Draw clip volume keyframes or record fader automation for those moments.

A practical hybrid is:

1. Use Ducker or sidechain compression for the consistent baseline.
2. Bypass or reduce it for a shot where the music must lead.
3. Shape the exception with keyframes that begin before and finish after the words.
4. Check the handoff into the next automatic section for a level jump.

Manual moves are slower, but they follow story rather than threshold. Use them where meaning matters more than repeatability.

Fix Pumping, False Triggers and Bad Renders

The music pumps between words

Increase Hold or lengthen Recovery/Release so short speech gaps don't restore the full bed. If reduction is deep, make Duck Level milder or lower the compressor ratio.

The first syllable is masked

Add enough Lookahead in Ducker or shorten compressor Attack. Confirm the trigger track begins with the actual consonant and does not have a late clip fade.

Breaths and room noise trigger the music

Clean or edit the source, then retest. On a compressor sidechain, adjust Threshold so useful speech crosses it but the noise floor doesn't. Don't gate aggressively enough to clip word endings.

The music never returns

Solo or Listen to the detector source. A noisy dialogue track may remain above threshold. Also check Hold/Recovery or Release, and make sure another dialogue source isn't continuously active.

The timeline is clean but the render crackles

Render a short problem range, then bypass Ducker or sidechain and render it again. If the fault follows the processor, save the project, test the current Resolve 21 maintenance build and use keyframes or rendered automation for that delivery rather than claiming the whole mix is fixed. Verify the exported file in an external player.

Finish the Mix After Ducking

Ducking creates separation; it doesn't set final program loudness. Listen on headphones and small speakers, inspect the loudness meters and check the full mix for peaks after all busses and processing. The Resolve LUFS and audio-level guide handles that delivery pass.

Export a short representative section before the final render. Include a strong music entrance, normal dialogue, a pause and the loudest transition. If that section is clean, render the full program and check the resulting audio outside Resolve. The audio export guide covers stems and audio-only files.

Frequently Asked Questions

Is audio ducking available in DaVinci Resolve Free?

Yes. Ducker Track FX is available in the free edition. AI Audio Assistant is Studio-only. Fairlight's regular mixer and Dynamics tools provide the non-AI route for controlled mixes.

Which track gets the Ducker effect?

Put Ducker on the track you want to lower, usually music. Select dialogue as its source. The source triggers the change; the target receives it.

What is the difference between Ducker and sidechain compression?

Ducker is a purpose-built Track FX with direct depth and timing controls. Sidechain compression uses the Fairlight Dynamics compressor and can use a track or bus as the detector, making it better for bus-based mixes.

Can several voice tracks trigger one music Ducker?

Yes. Current Resolve versions let you add multiple source tracks in the Ducker. This is useful for dialogue split across speakers, microphones or voiceover tracks.

How much should music duck under dialogue?

There's no universal value. Reduce it only until the words remain clear on the intended playback devices. Deep, fast moves sound like pumping; dense music may need more space than a sparse bed.

Should I use AI Audio Assistant instead?

Use AI Audio Assistant in Studio when you want a first-pass mix across categorized dialogue, music and effects tracks. Use Ducker or sidechain when you want predictable control over one specific relationship.

This guide is part of the Fairlight audio hub. Start there for the complete path from track organization and dialogue cleanup through loudness, bus routing and delivery.

Related guides

• Fairlight Audio in DaVinci Resolve: the hub: the dialogue chain ducking belongs to.
• Fairlight Compressor Settings for Dialogue: the same dynamics engine, aimed at one track.
• Audio Levels and LUFS in DaVinci Resolve: checking the mix after music stops fighting dialogue.

Jason Miller I run DaVinci Resolve Club as an independent publication: hands-on edits, color grading breakdowns, Fairlight sessions, Fusion tests, and honest notes on where Resolve gets in the way.