Why does usb audio sometimes quit?
I have some externally powered speakers (Audioengine A2+) connected by USB. Normally they work fine, but sometimes when I use the Preferences>Sound menu to select "Audioengine A2+" as the output, I get no sound. Switching to the other outputs - such as "iMac Speakers" or "External Headphones" the sound plays normally. If I turn off the power switch on the A2+ speakers, then turn them back on - the speakers will play again - until next time.
Is this more likely a Mac hardwware problem, a speaker hardware problem, or an Apple software problem?
2020 iMac 27" 5k Retina (iMac20,1) running Big Sur, 11.6.4 (same problem with v.11.6.2)
Thank you
iMac 27″, macOS 11.6