Free Mac Audio Routing Tools – Apple’s AUNetSend & Receive

Routing audio around on a Mac, between software applications, or from multiple sources including hardware instruments, microphones, and the like, can be challenging when your needs go beyond simple playback. So if you’re making podcasts, working in audio production, or just have a need to get audio from one place to another on your Mac, read on…

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One helpful tool built into macOS is a pair of Audio Units (AU’s), Apple’s AUNetSend and AUNetReceive. As the pair of names implies, the pair is comprised of an Audio Sender, and an Audio Receiver. 

Both the Sender and the Receiver require an Audio Unit Host. An excellent free option is Hosting AU.

You can run as many pairs of AUNetSend and AUNetReceive as your host can accommodate, and have excellent options for the Data Format of the Audio you wish to send:

You can also select a custom port for the Send/Receive pair to work on, and set a password for the pairing if securing the audio stream is an importance, in a live or public venue, by example.

Much of my audio routing is done to optimize the amount of processing power I can use. So the lossless audio transmission AUNetSend & AUNetReceive afford, allow me to transmit audio to multiple plugin hosts for distributed processing.

Similarly, AUNetSend & AUNetReceive are effective to set up separate audio monitoring chains. I like to have an instance of AUNetSend on a return track, this allows me to quickly send audio from different tracks out from that return track for monitoring, cueing, or processing.

You can send as many audio sources through the Sender as you like, or  you can set up separate instances if you wish to send mono channels, which is also nice as you can send each mono channel to a receiver that can be located anywhere in the audio chain, allowing a great deal of audio channel flexibility for mixing and the like.

Another way to utilize AUNetSend & AUNetReceive is to use them on multiple tracks within your DAW or plugin host. You can use them as a second audio source or receiver on a track, and you’ll probably think of other ways to fit your needs.

Below I have Ableton Live 10 with 2 Instances of AUNetSend, on Track 2, and on A Return Channel. Both are sending Audio to Hosting AU, where as you see I have an additional 3 slots below each instance of AUNetReceive, to process my audio through different AU & VST Effects, before the Audio is ultimately played out through the Presonus Quantum audio interface. 















I could just as easily here, set up pairs of AUNetSend in Hosting Au, and route the processed audio back to Ableton Live with receiving pairs of AUNetReceive, or forward the audio on to another plugin host for recording, like Audio Hijack (which hosts AU plugins).

Audio Hijack from Rogue Amoeba is another excellent audio router for the Mac, allowing you to record and route audio from and to any sources. Here’s an example of AUNetSend & AUNetReceive in Audio Hijack:

Rogue Amoeba – Audio Hijack Hosting AUNetSend & AUNetReceive

I’ve noticed AUNetSend & AUNetReceive are often overlooked as excellent free solutions to overcome a good many situations in which audio routing with and through multiple inputs and outputs is needed. With the free AU plugin host, Hosting AU, the Mac gains some robust, low-latency audio routing with its built-in plugins.







9 replies »

  1. Yes, I love these Apple plugs. I have been trying to work out a way to use AU Net Receive in ProTools using Bluecats Patchwork. The only problem s that unfortunately, the AU Net Receive plug is not available as an AU plugin in the plugin menu.. It seems to be deeply embedded in the OS. Would love to be able to get at it!!


    • Matt – Unless you’re on Windows, AUNetSend & AUNetReceive should be on your Mac. Open up Audio MIDI Setup, then click “Audio MIDI Setup” in the top Menu, then click Preferences, and then click the Info icon in the Preferences Window. In the List, highlight “CoreAudio.component” once highlighted, you can scroll down through the list of all the Apple AU’s on your Mac – Here’s a link to a screenshot (sorry haven’t figured out how to get my images in comments here):

      Liked by 1 person

      • Oh yes, I do see them when using, for example, Logic. However, they are not available to many applications, including Bluecat Patchwork. This would be a super handy cheap alternative to using SourceElements Nexus Pro


    • One other piece of info that might explain the difficulty finding AUNetSend & AUNetReceive. AUNetSend will be listed as an Audio Unit Effect (aufx is the Apple abbreviation, which you can see on the image from my other reply). AUNetReceive will be listed as an AU Instrument (technically a Generator), its abbreviation is augn. Seems counter-intuitive that AUNetReceive would be an Instrument/Generator, you’d think the AUNetSend would be the Instrument/Generator. But since it’s AUNetReceive that’s playing out the Audio its received via AUNetSend – it’s Generating the Audio we hear, while AUNetSend is just an Audio Effect that’s sending Audio to the Receiver to play. And since you do select the converter options – the AUNetSend is performing resampling of that Audio so it can pass through the Mac’s hardware abstraction layer (HAL) to the AUNetReceive audio endpoint.


    • A possible alternative using more Rogue Amoeba (RA) software is to create a Loopback device using RA’s “Loopback” program, and then in RA’s “Audio Hijack” you can pipe an “AU Net Receive” to the loopback device, which effectively turns the AU Net Send into a standard device that can be picked from Bluecat’s patchwork’s Audio Input list. That’s if I understood what you are trying to do! (I tried it and it worked using the Bluecat Patchwork demo application.)


  2. AUNetReceive doesn’t appear in the AudioUnits plugin list. Any idea how to fix this? I’m running Live 10.0.6 on MacOS Sierra 10.12.6


  3. Actually it’s pretty easy to make these plugins available to other hosts and also the BlueCat Patchwork adapter:
    Here’s how: The CoreAudio.component, that is actually a ‘bundle’ of several Apple audio components, resides in:
    If you copy that CoreAudio.component (I wouldn’t move it out of that directory myself) into the AU Unit folder, which is at /YourHD/Library/Audio/Components,
    it becomes visible and available to AU Hosts that can utilize AU FX and AU Generators. Hint: Live doesn’t seem to like the latter category, but Patchwork doesn’t mind and you can choose whichever plugin you want from a pop-up window.

    Now here’s the catch:
    I couldn’t make the AUNetReceive get sound on any Sierra machine (10.12.6), although it showed the connection. High Sierra fared even worse, not even seeing the AUNetSend on the network.
    This only worked on El Capitan and Yosemite, although I’ve seen reports of success.
    Does anybody know why and how to fix this?


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