Run audio plugins on your live microphone, then use the processed signal as a microphone in any other app.

PlugInput is a macOS menu bar utility. Load a compressor, de-esser, EQ, or gate onto your voice without opening a DAW, and Zoom, Discord, Slack, Teams, and OBS will pick up the processed signal directly.

microphone -> [ your effect chain ] -> PlugInput -> Zoom / Discord / OBS
                                            |
                                            +----> your headphones

• Chain up to 8 Audio Unit effects, in any order, with per-effect bypass.
• Pick which input channel your microphone is on, for interfaces with more than one.
• Each plugin opens its own vendor interface. Several can be open at once.
• Settings, chain order, and device selection are saved and restored on launch.
• Optional headphone monitoring, independent of what other apps receive.
• Latency readout, input level meter, and an activity log.
• Works alongside an existing BlackHole installation.

macOS 14 (Sonoma) or later, on Apple silicon or Intel.

Download the latest PlugInput-<version>.pkg from Releases and run it. The installer places the app in /Applications and an audio driver in /Library/Audio/Plug-Ins/HAL, then restarts CoreAudio so the device appears immediately.

On first launch, macOS will ask for microphone access. PlugInput cannot capture anything until you grant it.

If PlugInput becomes your system microphone. macOS sometimes makes a newly installed audio device the default input. If that happens, apps that follow the system default will hear silence. PlugInput notices and offers a one-click fix in its menu; you can also set it back yourself under System Settings > Sound > Input.

To remove everything later, run the uninstaller that ships inside the app:

/Applications/PlugInput.app/Contents/Resources/uninstall.sh          # app and driver
/Applications/PlugInput.app/Contents/Resources/uninstall.sh --all    # also delete settings

1. Click the waveform icon in the menu bar.
2. Choose your Input: a microphone or audio interface. On an interface with several inputs, pick the Channel your microphone is plugged into.
3. Open the Effect chain and search your installed Audio Units. Click one to add it.
4. Press Start.
5. In Zoom, Discord, or OBS, select PlugInput as the microphone.

Effects process top to bottom. The same plugin can appear more than once.

Bypass takes effect instantly. Adding, removing, and reordering rebuild the audio graph and cause a brief dropout.

The Monitor checkbox controls whether you hear yourself. Turn it off when you are on speakers rather than headphones, or the processed output will be picked back up by the microphone and feed back. This is especially loud with a compressor in the chain.

Monitoring does not affect what other applications receive.

Turning it off does more than mute: PlugInput stops opening your output device altogether. That matters if you use the same interface in a DAW — with monitoring off, PlugInput leaves it entirely alone.

swift build && swift test     # library and unit tests
./make-driver.sh install      # build and install the audio driver (asks for sudo)
./make-app.sh release         # assemble PlugInput.app
open PlugInput.app

make-app.sh is required rather than cosmetic. A menu bar app needs LSUIElement, and macOS grants microphone access only to a bundle whose Info.plist declares NSMicrophoneUsageDescription. Running the raw SwiftPM binary produces a dock icon and silence.

To build a distributable installer:

./make-pkg.sh              # unsigned, for local testing
./make-pkg.sh --notarize   # signed and notarized, needs Developer ID certificates

No sound reaching other apps. The most common cause is microphone permission. macOS returns silence rather than an error when access has not been granted, and every layer of the stack reports success. Check System Settings > Privacy & Security > Microphone.

Checking what the app is doing. A menu bar app has no console, so PlugInput writes to the unified log:

/usr/bin/log show --last 5m --info --predicate 'subsystem == "com.pluginput.app"' --style compact

The Activity panel in the app window shows the same transcript.

Resetting. ~/Library/Application Support/PlugInput/session.json records the chain that loaded and whether the engine started. Delete it to return to defaults.

Verifying the audio path directly. A separate harness listens on the virtual device from its own process, the same way another application would:

cd Spike && swift build
./.build/debug/PlugInputSpike listen 4 PlugInput

A broadband reading well above -120 dBFS means signal is arriving. Disregard the RESULT: FAIL line, which looks for a 440 Hz test tone that a microphone does not emit.

• Plugins load in process. Out-of-process loading is AUv3 only, and most installed Audio Units are AUv2. A plugin that crashes will take the app down with it. Settings are autosaved partly for this reason.
• Eight effects maximum. Each adds latency. The window shows a running total and warns past roughly 5 ms, where talking over your own monitoring becomes difficult.
• Audio Units only. VST3 is not supported. See ENGINEERING.md.

The app builds a private CoreAudio aggregate device, binds an AVAudioEngine to it, and inserts your chain between the input and output nodes. Processed audio is written to a loopback driver that other applications open as an ordinary microphone.

That driver is what allows the device to appear under its own name. A CoreAudio device name is a compile-time constant, and macOS keeps no user-level override for HAL devices, so the name cannot be changed at runtime.

ENGINEERING.md documents the architecture in detail, along with the failure modes encountered while building it. Nearly all of them are silent: the audio stack reports success and delivers nothing. Read it before changing device or channel-map code.

PlugInput includes a modified build of BlackHole by Existential Audio, used as its loopback driver and renamed so the device is identifiable. This is not the official BlackHole binary and is not supported by Existential Audio. Please direct any issues with PlugInput here rather than to them.

BlackHole is licensed under GPL-3.0. The corresponding source is BlackHole v0.6.1 together with the build flags recorded in make-driver.sh.

PlugInput is released under the MIT License. See LICENSE.

The bundled audio driver is a separate work under GPL-3.0, distributed alongside the app rather than linked into it. See THIRD-PARTY-LICENSES for the details, including what was modified and where to get the corresponding source. Its full license text also ships inside the driver bundle.