Audio Loopback Driver

Audio Loopback Driver is an M1 compatible virtual audio loopback driver for macOS. It creates a virtual audio device that allows you to route audio between applications.

This driver supports macOS Apple Silicon (arm64/arm64e) and macOS Intel (x86_64) platforms. It uses Apple's native AudioServerPlugIn API (HAL) to create a virtual audio device that appears in macOS like any other audio interface. The driver provides 2 channel audio at 48kHz sample rate (both configurable), with zero-latency loopback between input and output streams. Volume and mute controls are built-in for easy audio management.

Note: On macOS 26+ (Sequoia and later), a paid Apple Developer Program membership is required to load custom HAL audio drivers. On macOS 25 and earlier, the driver can be built with ad-hoc signing.

To install, copy the driver bundle to the HAL plugins folder and restart CoreAudio:

sudo cp -R Driver.driver /Library/Audio/Plug-Ins/HAL/
sudo killall -9 coreaudiod

Once installed, open Audio MIDI Setup and you will see "Audio Loopback" as an available audio device. To use it, configure an app to output to "Audio Loopback" (like Safari or Spotify), then configure a recording app to input from "Audio Loopback" (like Audacity or GarageBand). Audio will flow from the output app directly to the input app through the virtual device.

To build from source:

# On Apple Silicon, coreaudiod commonly runs as arm64e, so build an arm64e slice.
xcodebuild -project Driver.xcodeproj -scheme Driver -configuration Release build ARCHS=arm64e CODE_SIGN_IDENTITY="-" CODE_SIGN_STYLE=Manual DEVELOPMENT_TEAM="" PROVISIONING_PROFILE_SPECIFIER="" CODE_SIGNING_REQUIRED=NO

To uninstall:

sudo rm -rf /Library/Audio/Plug-Ins/HAL/Driver.driver
sudo killall -9 coreaudiod