Call audio update: Audio Hijack

With Audio Hijack 4, Rouge Amoeba added the ability to manually edit connections. I’ve been an occasional Audio Hijack user since 2004[1], but I knew right away that this had the potential to bring it into daily use.

As I wrote a couple years ago, I had been using a DAW, Reaper, to route and process my everyday call audio, but that seemed heavy, and definitely not what it was designed for.

Instead of Reaper, I set up Audio Hijack. As with before, I’m using BlackHole to create two virtual audio devices: a 2-channel device I use as the call app’s mic, and a 16-channel device I use as the call app’s speaker. Then, Audio Hijack looks like this:

An Audio Hijack 4 session that routes and processes my call audio. It's a series of blocks and connecting lines that I walk through in detail in the rest of this post.

It looks like a lot, but talking through it from top to bottom, left to right:

That’s it for mic routing, but there’s one more thing in the Audio Hijack session. Sharing application audio with a call can be tricky and unreliable (“Can y’all hear this?”), so I keep a block around that I can turn on to capture application audio and send it to both my ears and the call. If I can hear it, they can hear it. Plus, I didn’t have to un-share and re-share my screen to make it happen.

One other thing I’ve started doing is using a global shortcut to mute myself. Usually when I’m talking in a meeting, the call app isn’t in the foreground, and I like to be able to quickly toggle it because (let’s be honest), with a mic in my face, I worry about mouth sounds. (Unless you enable Original Sound in Zoom or a similar feature in other apps, this probably isn’t a huge concern, but still….)

Screenshot of MuteKey in my menubar with its settings open, showing that it's unmuted and other settings I'm about to describe

There are a gazillion of these little apps out there. They all seem just a little scammy. I’d like to use Mic Drop, but it doesn’t support muting only a single device at a time. I ultimately settled on MuteKey. It’s not perfect: I need to quit and relaunch it after the computer sleeps and/or it’s unplugged from the selected device, and sometimes after quitting while muted it turns down the input level, so I need to use SoundSource or Audio MIDI Setup to turn it back up. But it gets the job done. I use the shortcut Space because I can easily use it one handed with either hand — very handy for pointing with a mouse while talking on a call.

One of the reasons I like being able to hear myself in my headphones is that when the USB interface is muted with this app, I can’t hear myself either. So if I can’t hear myself, neither can the call, and if I can hear myself, the call can hear me, too.

So there’s the latest on my call audio setup. Let me know if you have any questions or suggestions on how to sound even better!

  1. In college I set Audio Hijack to automatically start and record the Real Audio (remember that‽) stream of Morning Edition on Michigan Radio from 05:00–07:00, then put it on my iPod to listen to throughout the day. Yep, I invented podcasting. ↩︎