Playing audio clips into webinars or calls

To play back pre-recorded audio into a call, webinar or remote recording session (or radio livestream for that matter), you’d traditionally use a player device, a hardware mixer and a sound interface. It’s relatively easy to do it in software though.

A convenient all-in-one solution is Rogue Amoeba’s Loopback.

Here’s a recipe for a homemade version. It might at first seem complicated but the example configuration further down is pretty straightforward.

  1. Install a virtual audio device (recommendation for this use case: Ultraschall Hub)

  2. Install LineIn, Audio Monitor or LadioCast (recommendation: LadioCast)

  3. Setup

    • If you picked LineIn or Audio Monitor
      • create a multi-output device with the virtual device and your headphone output
      • configure LineIn or Audio Monitor to send your microphone input to either the virtual device or, if you want to monitor your voice, to the multi-output device. Activate LineIn or Audio Monitor.
      • configure your playback software to play your pre-recorded audio through the multi-output device
    • If you picked LadioCast
      • open it and in the right column, select your headphones as Main Output
      • select a virtual audio device as Aux Output 1
      • in the left column, select your microphone as Input 1 and activate Aux 1 below, and, if you want to monitor your voice, activate Main as well.
      • as Input 2 select a virtual audio device that’s different from Aux Output 1. If you’re using Blackhole, select it, but change the channels to 3 and 4, using the tiny up-buttons. Activate Main and Aux 1.
        Example configuration with BlackHole:

        Example configuration with Ultraschall Hub:
      • configure your playback software to play your pre-recorded audio through the same virtual device you selected as Input 2. Again, for Blackhole you must select the respective channels, which might not be an option in every playback software.
  4. Go to your webinar/call software and change the microphone/input setting to the virtual audio device. (For BlackHole, if you have the option to select channels, pick 1&2)

Example configuration

Here we use LadioCast and the two Ultraschall Hub devices Aux and Stream. We want to play our audio from Quicktime or iTunes. We use the Mac’s internal microphone.

  1. Configure LadioCast just like in the screenshot above (the Ultraschall Hub one).
  2. Set the Mac’s sound output to the Ultraschall Hub device Aux
  3. Set the microphone/input of the app we want to use for the call to Stream
  • It looks like this in Skype:
  • Or like this in Zoom:
  1. DONE

Bonus: Use LadioCast to mute your mic while your pre-recorded audio is playing.

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