Using Multiple USB Audio Devices in Garageband

Audio Midi Setup

I’ve been asked a number of times about this, and the answer is quite simple — though frustratingly hard to find.

The way to do it is through an application with the confusing name of Audio MIDI Setup (found in your Mac’s Applications ? Utilities folder). This program can be used to combine any audio inputs on your computer into one “Super Input” (called an Aggregate Device be Apple) that can be used in any program.

The cool thing about this is that you can assign these inputs to be different channels of the Aggregate Device, so you still get the same control in Garageband that you would with a full set of inputs on a device like a firewire mixer. You can also use this Aggregate Device in iChat or Skype for multi-way chat — just select it as the audio input in the program’s preferences.

Here are the specific directions from the Audio MIDI Setup help file:

To combine audio devices:

  1. Open Audio Midi Setup in the Applications/Utilities folder.
  2. Choose Audio > Open Aggregate Device Editor.
  3. In the editor window, click the Add (+) button to create an aggregate device. You can select the device and rename it.
  4. In the Aggregate Device Structure list, click the Use checkbox of each device you want to include in the aggregate device. The list shows the currently connected audio devices and the number of input and output channels for each.
  5. To set the clock of one device as the master clock for all the combined devices, click the Clock radio button beside the device name.
  6. After selecting the devices you want combined, click Done.

There are some more options to play around with in the program, but that should get you headed in the right direction.



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18 responses to “Using Multiple USB Audio Devices in Garageband”

  1. praduman mehta Avatar
    praduman mehta

    i have windows vista and when i use skype it gives the msg ‘the computer has no sound recording capabilites ‘ and in control panel sound there is a tab recording which has nothing install in it to support that feature of skype.
    please let me know from where can i download the device or driver


  2. Brian Avatar

    Hey Adam,

    I am trying to run 3 Samson C01U microphones into GB. I can get them all into the program via and Aggregate Device. I assign them to their own tracks in GB. Everything works great until… For some reason and (from what it seems) totally randomly, the audio starts to “crackle”. I could send you a sample if you would like. Any ideas on what is going on or what to try to get this to stop. I have searched high and low and I can’t find much on this topic. On post on version tracker said that this happened to a guy after installing Audacity on his Mac. I do have Audacity installed.

    Thanks in advance.

  3. Adam Avatar

    Praduman: I don’t really know much about Vista – I’m a Mac guy who hasn’t really used Windows since Win2K. Sorry I can’t be more help!

    Brian: The first thought I has was CPU-related. USB is quite processor hungry at times, and multiple inputs could bog the system down to the point that it can’t handle all of them. Are any other programs running when you get this problem? I don’t know what Audacity would have to do with that. Have you tried removing Audacity or making a new user account and testing things there?

  4. Brian Avatar

    Hi Adam,

    Thanks for the reply. I figured it out. I need to post this on the Apple Discussion Boards. I put this together after talking to a friend that does professional recording. Thanks Justin.

    Justin said it sounded like the “Clock” was getting off and the audio was going out of sync in a real bad way. So I started to dig and found this on Samson’s site about using the C01U as an Aggregate Device to use it with Logic. “The list at the bottom of the window will show all the audio devices connected to the computer. Select the ones you want the device to use by checking the ‘use’ button. For instance, if you only have a CO1U connected you will need to check CO1U and Built-in Audio. Check the clock button on one of the devices, not the CO1U.” That last part struck me. “NOT the C10U”. So I added the internal microphone from my MBP to the AD and set it as the “Clock”. Success!

    Per another forum posting I found I added an output to the AD as well. The poster said that he had to add an output device to the AD to get Logic to see it. I did that as well since I figured what could it hurt.

    All is well now that I know I did not spend $500 on three C10Us for nothing.

    My old podcast: Wedding Plan Podcast
    My new podcast: NE Ohio Wedding Show Coming Soon!

  5. Sid Much Rock Avatar

    Hey there Adam and Brian. I’m running into this same issue.

    I’ve a Snowball Blue mic that I had with me on the road for remote recording and I’ve a M-Audio with an AKG at home that I use in my “studio.” Recently I had the need for two mics so I wondered if I could use both of them. Through the Audio Midi Setup I created a device that was both devices. Crackle city. One works for a bit then suddenly crackle and the other is crackle from the get go.

    I added in the built in audio, doesn’t make a difference. I added an output device to the mix, no difference. And no difference regardless of which device I map the clock to.

    Any ideas?

  6. Michael Avatar

    Thanks for this post. I was searching around for a solution that didn’t include purchasing an audio mixer.

  7. Michael Avatar

    I tested the setup you described, using two Plantronics headsets. I got the audio-in portion working great in Garageband; both mic’s could be heard on separate channels, etc. However, when it came to audio-out, I could only hear audio through one headset. I added the outputs to the aggregate device, and set it as the output in Garageband. Unfortunately, none of the configurations I tried in the Audio Midi setup, allowed me to hear audio from both headsets. Do you know how to get this to work properly? Thanks in advance.

  8. Phil Avatar

    I got the mics not to “crackle” by doing the following:

    Make sure GarageBand is set to use “Built-In Audio” and then quit it. Then open MIDI setup and follow the instructions given previously (above).

    Here’s where something gets funny sometimes. Open Sound in System Preferences and choose Aggregate Device for output. If Aggregate Device does not show, unplug everything and start over again. Once you have Aggregate Device chosen, launch GarageBand and open your project. Go to Preferences and choose Aggregate Device in the sound input options panel. Make sure you apply a microphone to each track that needs one and test it. If you don’t apply a microphone to your track it will still crackle and once it does you might have to start all over so apply a mic to your track before you test.

    This has worked for me so far. Good luck with it!

  9. azkid Avatar

    You may want to mention that this ability to add aggregated devices, is only available in Tiger, OS X 10.4 or later OSs. I had to research much to pin this down.


  10. Sound Studio 3.0 Mac…

    I’ve been asked a number of times about this and the answer is quite simple though frustratingly hard to find.The way to do it is through an application with the confusing name of Audio MIDI Setup found in your Mac’s Applications ? Util…..

  11. Jon Payne Avatar
    Jon Payne

    I wonder if someone could do some screen shots of all the steps required for this setup? I have 2 USB headsets that I want to have in 2 channels in garage band for a 2 person podcast. I set up the aggregate device and both mics work, but audio only is in one headset, not both. So I guess I did not set it up properly. Ideas?

  12. satyr42 Avatar

    thanx – i’m going to try the aggregate device setup – my problem is alittle different – I have a Korg Nano Keyboard and a Nano Pad – both USB – i want to run them simultanously – but assign them to two different tracks – (keys= organ/synth pads=drums) I don’t know if I’m explaining it properly – but I hope you’all understand what I mean – will this work for me also ????

  13. […] Using Multiple USB Audio Devices in Garageband | Adam Weiss: Podcast Consultant […]

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  17. Matt Avatar

    Great post. Working on setting up everything for a podcast I’m starting soon.

    I use the aggregate device for both of my usb microphones, and they set up easily in garageband.

    The last thing that seems impossible for me to get info on, is how to record a Skype call in garageband while we’re using both of those usb mics.

    So far I’ve seen people give instructions for one or the other. But never both together, and I can’t figure it out.

    Any tips?

  18. Tanesha Avatar

    I couldn’t refrain from commenting. Perfectly written!