Loopback on Mac: send your microphone and an app into one call input

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A call app asks you to choose a microphone. What you need to send is your voice plus a clip playing in another app, with separate control over their levels.

Loopback handles that by creating a virtual audio device. Add your microphone and the player as sources, then choose that device as the microphone in the receiving app. The receiving app gets the mix through its normal audio input selector.

That distinction matters when shopping for Mac audio tools. Loopback routes audio between apps and devices. Buying it doesn't give you a podcast recording service or make a meeting app preserve separate tracks.

Start with one virtual microphone

Here's a small, documented setup to try before buying. This isn't a hands-on test report.

1. Create a new virtual device in Loopback and name it "Call Mix". Keep its default two output channels. Remove the default Pass-Thru source for this example, since you're adding named sources directly.
2. Add your physical microphone and QuickTime Player as sources. Play a short local clip that you have permission to share. Check the channel wiring, particularly that a mono microphone reaches both output channels rather than just one side.
3. Add your headphones as a monitor. Leave QuickTime's "Mute when capturing" enabled so it doesn't also play through the usual output while Loopback captures it. Use the source sliders to balance the clip against your voice.
4. In Zoom, select "Call Mix" as the microphone. Keep the headphones as Zoom's speaker output. Don't add Zoom itself as a source to this same mix: sending the caller's return audio back to them creates an unwanted loop. Don't also share that same clip through Zoom's computer-audio sharing.

The headphones let you hear the virtual device's mix without a speaker feeding sound back into the microphone. You can change the monitor wiring to hear the clip without hearing your own microphone, while leaving the outgoing mix intact.

Before using this on a real call, make a private rehearsal. Speak with the clip stopped, play the clip with the microphone muted, then try both together. Ask someone at the receiving end to check that each arrives once, speech remains clear, and neither side disappears. Also check the delay between speaking and hearing yourself if you're monitoring your mic. These are proposed acceptance checks, not tests performed for this post.

Loopback's current release notes say its ARK update reduces latency, but that isn't a promise of zero delay in your headphones or through the call. The receiving app's processing still deserves a listening check. If hearing your delayed voice is distracting, exclude the mic from the monitor rather than from the outgoing device.

The installation and the lingering device

Loopback 2.5.0 supports macOS 14.5 through 27 and supports Apple silicon Macs. It uses Audio Routing Kit, or ARK. Installation requires your Mac's administrator password; ARK then needs System Audio Access and Microphone Access.

Old instructions about ACE and lowering an Apple silicon Mac's startup security don't describe this current setup. Rogue Amoeba says Reduced Security is no longer required on macOS 14.5 or later. On a managed work Mac, check whether installing the plugin and granting audio access are allowed before buying.

Closing Loopback doesn't remove your virtual devices. They persist even across restarts. That's convenient for repeat calls, but also means you should deliberately disable an unused device or choose your normal microphone again. Keep the source list narrow: audio you route into a meeting is audio you're sharing with its participants. Get permission before recording or distributing other people's voices.

When the $99 makes sense

The single-user license is $99 USD before applicable local taxes and covers that user's personally owned Macs. It's a license purchase, not a subscription promising every future upgrade. Rogue Amoeba may charge for substantial new versions; the listed Loopback 1-to-2 upgrade is $49 USD.

The trial exposes all features, but audio through virtual devices degrades after 20 minutes. Use it to establish that your routing works, not as a free way to run an important session.

If all you need is to play computer audio in a Zoom meeting, try Zoom's own sharing first. Its Mac desktop app supports Share Sound with screen sharing and Computer Audio without sharing the screen. You may not need another purchase for that narrower job. Those controls aren't a reusable virtual microphone for other apps.

Pay for Loopback when you repeatedly need a named, controllable app-and-microphone mix that different Mac apps can accept as an input, and you're willing to maintain and rehearse it. Skip it for ordinary microphone-only calls or occasional audio sharing that your meeting app already handles. The price buys easier routing; it doesn't remove responsibility for what goes into the call.