Mac User Forever and I Never Knew about Aggregated Sound Output

I have been using Macs of every flavor forever and I am embarrassed to say I did not know it is possible to combine audio outputs. In retrospect it is an obvious feature but somehow I never came across it.

My Mac has multiple speakers - one each in several monitors, built-in speaker, and an external speaker system through the audio output. At various times I have experimented with which works best depending on how I arrange my office.

It turns out that there is a macOS supplied utility called Audio MIDI Setup which lets you create a virtual Aggregate audio device which combines any or all physical audio output devices.

Am I last to the party or is this an oversight for others too?


I had no idea either. That could be pretty cool…

You are not alone!
Never knew this was possible.

I really don’t know what I need it for though?
I don’t create music, but maybe it’s useful for normal deadly people?

Certainly is news to me!

Better sound if you have multiple speakers in your office computers

Or stream music to multiple locations in your house

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Wow. That’s cool. Who knew!

It is pretty nifty in combination with a virtual sound device like GitHub - ExistentialAudio/BlackHole: BlackHole is a modern macOS virtual audio driver that allows applications to pass audio to other applications with zero additional latency.

You can do things like send an app’s audio to an aggregate device which then sends it both to some headphones (for monitoring) and also to the input of another app.

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I did discover this a couple of years ago when messing around with airplay, but I have had a difficult time getting it to work consistently on my 2015 iMac.

This will alway get my vote for Most Cryptically Named Utility.


I was dealing with MIDI a lot in a live music setting back in the late 90’s. I don’t think I used it for this particular application (multiple speakers) but got pretty familiar w/ the app. It’s quirky.

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This appears, at first glance, to enable one to bridge my external audio interface with the standout system output and thus be able to control the volume with my external keyboard’s volume keys without having to buy SoundSource or some other software. Has anyone set it up to do this? I purchased SoundSource last year solely so I could control my volume using my keyboard’s volume keys. I use an external Scarlett audio interface that my speakers are hooked up to.

I did discover that you do need some sort of additional software to control the volume of the Aggregated output.

SoundSource works.

I saw somewhere that Soundflower may work though I have not tried that

Ie, if you listen to something not in the Music App (where you are able to choose multiples speakers)?

I can see a future for this. Sometimes when I look at streamed content it would be nice to hear the sound from my two Office Sonos instead of just one. :slight_smile:

Thanks for the input!