I'm sure there are people here with the appropriate equipment to do this, so how about someone connect their Amigas sound output directly to a recording device, perhaps the mic in on their PCs sound card, and record the Amigas sound output while playing back various sounds, using different sound output configurations?
Then these sounds could be examined in a sound editor, and we could all have a listen to the captured sound ourselves?
Heck, we could even be really scientific about it, and have the captured sounds not labelled as to what they are, and see if people can tell by ear, this way we could even use the original sound at say 16-bit 44.1 kHz as a control? That sound converted to 8-bit 22050 Hz, converted to say 14-bit 22050 Hz, and the original simply converted to 16-bit 22050 Hz. That gives us 4 samples to listen to and compare, which is not an unreasonable amount in my opinion, and if it's short, say 15 seconds of audio, it should be enough to make a fair comparison.
Of course, the original sound would need some low, medium and high frequency sounds, as well as some time with no sound being played, but if the original sound sample is picked well, this could really sort out the argument as much as possible. Sure, our opinions of the sounds would be subjective, but loading them into a sound editor would enable direct comparisons, would it not?
Heck, I could even do this with my A600 and my crappy PC, although I'd have to use the onboard sound on the 970A-D3P, but it would provide at least something we could draw conclusions from. I don't have the appropriate stereo RCA to stereo 3.5mm cable, but I could easily order one from ebay.
So, what do we think of this idea? Any merit, or am I barking up the wrong tree?