Setting up audio on Mac with BlackHole

BlackHole is a free virtual audio driver for Mac. It lets you send audio from your computer (for example from OBS or a media player) straight into Glossa, while you still hear everything through your speakers or headphones.

1. Download BlackHole (the 2ch version is fine) from Existential Audio. It's free.
2. Run the installer and follow the prompts. You may need to allow it in System Settings under Privacy & Security.

Step 2: Create a Multi-Output Device so you can still hear audio

On its own, BlackHole silently swallows the audio. A Multi-Output Device sends the sound to BlackHole and your speakers at the same time, so the room still hears it.

1. Open Audio MIDI Setup (in Applications, then Utilities).
2. Click the + in the bottom left and choose Create Multi-Output Device.
3. In the list, check both your normal output (your speakers, headphones, or house output) and BlackHole 2ch.
4. Optionally rename it something clear like "Glossa Output."

Step 3: Send your audio to BlackHole

Set the audio you want to translate to play through the Multi-Output Device:

• For all system sound, set the Multi-Output Device as your Mac's output in System Settings, then Sound.
• For OBS specifically, you can set OBS's audio monitoring device to BlackHole and set the relevant source to "Monitor and Output," which keeps your main stream untouched.

1. Open your service in Chrome.
2. In the audio input dropdown, choose BlackHole 2ch.
3. Speak or play your audio and confirm the level indicator responds, then start your stream.

If Glossa hears nothing, the most common cause is that the audio is still set to play only to your speakers rather than to the Multi-Output Device. Re-check Step 3.