Multi channel audio beyond straight routing with SoundPlayer or MoviePlayer

  • Beta Platinum


    i know there is multichannel audio output available using parameters in the MovePlayer and SoundPlayer on the Mac and I have these working beautifully with the Focusrite pre 8 I am using. But is there any way to specify audio channels for sound manipulated/generated within Isadora on the Mac platform? I have looked at numerous audio device output actors but can not find a parameter for multichannel selection.

    Best wishes


  • Tech Staff

    DISCLAIMER: This is a shot in the dark, I'm just spitballing ideas; I can't actually test these ideas because I don't have a multi-channel external audio interface, but here's how I *think* you'd go about it. 

    Ideally someone who actually works with multi-channel audio will come along and clarify this. If not, hopefully this'll at least highlight the places you need to look in order to tweak the proper settings.

    (Yes I'm tech staff, but I don't actually know how to do this because I've never needed to do it because I don't work with audio.)

    In Isadora (MAC ONLY) go to Output > Sound Output Setup

    In Isadora's Sound Output Setup, click "Set Default Sound Output Device".

    Your Mac's Audio Devices (inside "Audio MIDI Setup") will open.

    In your Mac's Audio Devices, click the "+" at the bottom to create a Multi-Output Device.

    What you're looking for might, instead of being a Multi-Output Device, be an Aggregate Device, which is created in a near-identical way.

    In your Mac's Audio Devices, select your your new Multi-Output Device (or Aggregate device) from the list at the left, then enable SoundFlower and your external device on the right.

    In your Mac's Audio Devices, select your your new Multi-Output Device or Aggregate device from the list at the left, then click the little gear icon at the bottom left and select "Use this device for sound output".

    Note: The little speaker icon next to an audio device marks it as the device being used for audio output (and the microphone is for input.
    Note: You may need to set SoundFlower or your new Multi-Output/Aggregate Device as the input the same way you set it as the output.

    It looks like an Aggregate Device is capable of routing to specific channels so that's probably your best bet(?) Set it up the way you want it and remember which channels are for SoundFlower and which are for your external device and refer to those in Isadora's Sound Output Setup(?)

    The routing might also need to be done In Isadora's Sound Output Setup, route Isadora generated audio to SoundFlower/Multi-Output/Aggregate Device channels

    My guess is that using a combination of using these things should let you use a Sound Input actor + MatrixMerger (or other AUMatrixMerger) to route sound internally in through SoundFlower and out externally to your device.

    Fool around with different combinations of Sound Input, Matrix Merger, AUMatrixMerger, and AudioDevice Output actors, they look like the most relevant ones. (Try different device settings on the Sound Input and AudioDeviceOutput actors to see if this plus the Multi-Output/Aggregate Device Channels + Sound Output Channels lets you route audio the way you are looking to do.

    Play with:

    • Sound Input actor's "device" input
    • AUMatrixMerger actor's "inputs", "in channels", and "out channels" inputs
    • AudioDeviceOutput actor's "device" input

    (All these setups are just hypothetically trying to re-route channels 1-4 to channels 5-8.)

    Play with:

    • Sound Input actor's "device" input
    • MatrixMerger actor's "inputs", "in channels", and "out channels" inputs
    • AudioDeviceOutput actor's "device" input

    I went through the other audio actors to find all the ones that might be relevant:

    Terrible TLDR (that may or may not be completely useless): 

    1) Try to route audio internally using SoundFlower + Multi-Output Device/Aggregate Device + Isadora Sound Output Setup or some combination thereof.

    2) In Isadora, grab the internally-routed audio from SoundFlower/Multi-Output/Aggregate Device with Sound Input Actor.

    3) Route the audio from the Sound Input actor, through an AUMatrixMerger or MatrixMerger actor, to an AudioDeviceOutput actor.

    4) On the AudioDeviceOutput actor's "device" input, choose your external audio device or your Multi-Output/Aggregate Device.

    5) Success(?) Failure(?)

    Again, I've never really messed around with audio at all so please feel free to correct me.

    Best wishes, 


  • Beta Platinum



    Thanks for alerting me to the ‘aggregate device’ option. I will try a method using these options.

    Best wishes


  • Tech Staff


    Hopefully the answer lies somewhere in one of those settings. Sorry, I wish I knew more about audio.

  • Are most the sound actors you have shown plug ins? I cant find them on 3.0.2 on my mac.



  • Tech Staff

    @andy-demaine-iic said:

    Are most the sound actors you have shown plug ins?

     All of those are native audio actors on Mac. Not sure how they could not show up for you. What OS?

  • Perhaps you checked the Core Audio option in the preferences.


    in that case you will see only these actors:

  • Beta Platinum

    @woland said:

    Success(?) Failure(?)

    Hi Lucas,

    Firstly, thank you for going through all of those options so methodically. The Force is strong with you.

    I have also gone through many procedures hinted and highlighted by you in your informative post. But I have to say that I was unsuccessful in outputting audio to individual channels through the Mac AU audio modules.

    Where the option looked most promising, in the system settings for audio setup - create Aggregate Device, I could only appended one device to another increasing the number of channels available, but it did not allow any options for mapping those channels. I could create custom names for the channels and that is about all.

    These audio plugins are from Apple so they are neither the responsibility of Isadora nor do they meet Isadora's policy of moving towards cross platform equity in terms of what is featured in the application on Windows and Mac. So I do not expect any resolution anytime soon in terms of these particular set of modules available through the the Mac version of Isadora and Apple's core audio features.

    One thing that did strike me as odd (but probably expected behaviour), was that output channels 'out channels' are a variable input parameter in the module AUMatrixMixer. However, indicated additional 'out channels' did not append additional outputs to the right side of the module. In addition, without the possibility of a parameter to select device output channels using the 'AudioDeviceOutput' module, the task of routing audio that is manipulated or modulated in Isadora to different sound outputs of the the selected device appears unfeasible even with a Aggregate Device setup.

    The multichannel parameters for assets already recorded in a movie or sound file all look to be working well. But I could not find a way to access multi channel output using any of the AU audio manipulation modules. Of course I could be wrong about this.

    best wishes


  • Tech Staff

    I can tell you that audio is on our list of things to expand in the very near future so hopefully we'll have some joy for you soon. Until then it seems the best way to go about this is to make movie files with multiple audio channels (if I understand correctly).