New here, relatively new to AM, but a fair amount of experience with PC audio...
OK, trying to post process 5.1 audio from Chrome using virtual audio cable to patch audio into AM. Chrome decodes 5.1 AAC fine directly to my 5.1 audio card. If I use stereo VAC as default windows audio device, set it as input in AM, and use audio card as O/P with a stereo graph, all works very nicely :-)
When I try to get it going with 6 channels (using aux ins & outs to handle additional channels, life gets more complicated. I need to force the VAC to be 6 channels otherwise Chrome output falls back to stereo. But if VAC is 6 channels, then AM throws an error when I enable audio (PortAudio -9999, which I beleive is to do with the number of channels).