Hosting AU on Big Sur - distortion!

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I've just spent a week or so setting up a good as new 2013 Mac Pro with a clean install of Big Sur, all is working fine. Logic running all plugins as expected.

Hosting AU opens for me and lets me use it as normally expected, however if I load any instrument and actually play it, the sound is horrendously distorted. This is the case with all plugins it seems.

Am using on a UAD Apollo 8 Thunderbolt interface at 48k.


UPDATE: It appears the distortion was due to using an Aggregate Device as my interface (Apollo combined with NI Komplete Audio 6, which gives me additional inputs). This setup worked with Hosting AU perfectly on Mojave & Catalina but apparently not with Big Sur.

If I set my interface to the Apollo only, the sound is fine as expected.
(The Aggregate Device still works perfectly well in Logic, etc. so very strange).


Hi redlester,

What I can think of is: are sampling rates of input and output devices different? If so Hosting AU applies sampling rate converter (resampler) automatically. However, there could be apps that change your sampling rate setting (in Audio MIDI Setup) on the fly. Especially while Hosting AU is running.

Even on such dynamic change of SR, Hosting AU should set appropriate SRC. But in some cases, this could fail or happen such distorted noise.

Basically unless you have any specific reason, I would recommend to set same SR for both in n out devices. In that case, Hosting AU will apply no SRC. It's designed so because Hosting AU doesn't touch to any audio setting of you, instead to say.

Good luck with your newly setting Mac!

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