Rob,

I've done a similar test with a frequency sweep from my PC. I'm running a professional 24/96 card (Echo MIA), so the quality is quite good. I've also got a Behringer test mic that I can use to balance things.

You're right about such a test being brutal! Things will be stable for a while, then you hit a tiny resonance point in the room and the tone jumps all over the place! I don't have an EQ, but I'd imagine that chasing everything down for a stable image to be like herding mosquitos.

Another point about imaging. I do some work with sample libraries and midi compositions. Yeah it's not like a live recording, but the results can be darn impressive these days, and it's cheaper than renting an orchestra to try out your ideas.

Anyway, the sample libs are 16-bit, but by the time you mix the levels of each instrument down, and given that you don't play every note ffff, the lsbs make it down to the bottom of a 24-bit recording. I did a piece recently that made a really wild, alive image. It wasn't natural, but was really interesting and vivid. I then mixed it to 16-bits... Gone. The image was just gone. It was as if every instrument was along a horizintal line, whereas before, the image was in/out, up/down.

I gotta get me more DVD-As.