macOS Sampling Rate Setting HostingAU

Official support for:



I’d like to use HostingAU for system-wide EQ in conjunction with BlackHole. I’d like to know if HostingAU can set output device sampling rate according to the input signal? For example, if I play a song that’s sampled at 44.1kHz, BlackHole sets itself to 44.1kHz and passes the signal to HostingAU, will HostingAU set the system output device to 44.1kHz as well?


P.S. Is it possible to have HostingAU running as a menu bar item instead of an always active background window?


Yes, you can set sampling rates of in/out in Audio MIDI Setup utility. In the Audio Devices pane, choose your output device, then select an option in the Format: section. Hosting AU will follow to the setting in there.

The right top corner of Hosting AU Core Window will display what SR it's currently running inside. Foe example, if input device SR = 96kHz while output device SR = 44.1kHz, Hosting AU will apply down sampling to 44.1kHz (or it will glitch :) ).

So please make sure input and output devices are set same SR rate for the best (probably in the most cases) result.

Depending on audio device, you may need to reselect the audio device in Hosting AU to let it know the update of SR in case if the top right corner display does't show updated SR rate.

For P.S. that's exactly what I plan to update if the next major version can be released. For now, if you close the Core Window, the result will be technically same or very very close. You can reopen the window by clicking Hosting AU icon again (or command-tab), get it back on top, then press command-0 (zero).

Thank you!


Thanks for the quick reply! So Hosting AU won’t be able to change the sampling rate of the output device automatically, for example, if output device is set to 48 kHz currently, and an input of 44.1 kHz comes in, Hosting AU won’t change the sampling rate of the output device to 44.1 kHz?


No, it won't, instead it applies down sampling to match different SR rates inside. In this way, Hosting AU doesn't touch to your audio setting of the system. The setting is used by other apps too, so it's something fragile to touch to.

This down sampler is needed in anyways for accidental cases. Setting same SR rates for in out is basically recommended, and in that case no resampler will be launched.

And be sure, if you set higher SR rate, the plugins in-between will process in that high SR rate which is more or less great for sounding, but will consume more energy :)


Is it possible to provide a toggle for this in an upcoming version?


Can't promise, but let me just consider...



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