I can get Poweramp to work in Android Auto by using "anyautoaudio" app with Android Auto set to any app in developer mode. You just have to start the app before plugging it in. song backgrounds are dark, but do appear. See pictures. Please Please add Android Auto compatibility Max so we won't have to use secondary apps to use it the main app!
Oneplus 3T factory oos 5.02 (8.0) Poweramp new beta 790 hi-res works headphone output flawlessy at 192/24 bit Poweramp alpha 7.0x up to 7.09 latest only works in hi-res headphone output to 48/24 bit. If you choose anything above 48k up to 192k at 24bit the audio loses major quality and sounds like an old-school telephone. Removing dvc and tweaking doesn't fix it. However it does work in hi-res 24bit at 48k and 44.1k Baffling.....