Add a Matrix Mixer

Last updated 6 August 2026

Every audio output already has a mixer — created automatically, with the output's name and the device's channel counts. A matrix mixer is the one you add yourself, and the reason to is that its input and output counts are yours to choose.

That makes it the answer to two jobs the automatic mixer cannot do: down-mixing or up-mixing between different channel counts, and adjusting individual channels of a stream on their way to an output.

Before you start

  • An audio output exists for the mixer to feed
  • You know the channel count going in and the channel count coming out

Steps

1. Create it

In the Outputs window, choose Create Matrix. (Create Ambisonic makes an ambisonic mixer instead — see below.)

2. Set its shape

Property

What it does

Name

How it appears as a destination on a sequence's audio channel, and in the Audio Routing matrix.

Inputs / Outputs

The channel counts. They do not have to match — that mismatch is the point.

Sample Rate

The mixer's sampling frequency.

3. Route it to an audio output

Open the Audio Routing window and connect the mixer to an audio output.

A matrix mixer reaches nothing on its own. Unlike an output mixer, which belongs to an output, a matrix mixer is free-standing — it must be routed to an audio output before anything it receives can be heard. This is the step that gets missed.

4. Set the matrix

Use Mixer Matrix to decide how each input channel contributes to each output channel, and Output Volumes to set the level of each output channel.

This grid is the whole feature: a stereo pair spread across eight speakers, sixteen channels folded down to two, or one input muted without touching the rest.

5. Send audio to it

In the Sequencer, set an audio channel's destination to this mixer — it offers "Assign to Matrix mixer" on hover, distinguishing it from an output mixer's "Assign directly to output".

Done when: the mixer appears both as a destination on a sequence's audio channel and as a row in the Audio Routing matrix, and audio played into it comes out of the routed device on the channels the matrix says.

Ambisonic mixers

Create Ambisonic makes a mixer for ambisonic material rather than channel-to-channel routing. It carries the decoder (AllRAD, SAD, MMD or EPAD), the normalisation convention (SN3D, N3D, or legacy Furse-Malham) and the channel ordering (ACN, or legacy Furse-Malham / B-format), plus an encoder and its post-processing.

Those conventions have to match what the material was authored to. If they do not, the result is not "slightly off" — it is spatially wrong.

Common Mistakes

  • The mixer exists but nothing is audible — it is not routed to an audio output. A matrix mixer is free-standing; routing it is a separate step.

  • Inputs and Outputs are greyed out — that is an automatically generated output mixer, not a matrix mixer. Its counts come from the device. Create a matrix mixer to choose your own.

  • Audio arrives on the wrong speakers — the Mixer Matrix decides which input reaches which output. Check the grid before suspecting the routing.

  • Ambisonic material sounds spatially wrong — normalisation or channel ordering does not match how the material was authored. Both are conventions, and both must agree.

Audio Mixer — the Audio Mixer reference, matrix and ambisonic in full

Audio Routing Window — the Audio Routing window

Remote Control: Audio Mixers (Output and Matrix) — driving mixer levels and mutes from outside Backstage