I was messing around with my speaker level settings tonight, and I think I've uncovered a bug of some sort. I had the CD input selected (Toslink 1 on my unit), and went into the speaker level calibration menu. Everything was fine. Then I switched to the DVD input, but decided I wanted to check the settings one last time. I went back into the level calibration menu, but this time, when I started the test tone, my left front speaker emitted a horrible piercing noise. At first, I thought I had blown it. However, when I exited the setup menu, I switched back to the CD input, threw in a disc, and it played fine. I went back into the level calibration menu again, and again I heard a VERY loud test tone. I tried switching the AVM 20 off and then back on, but that didn't help, so I unplugged it for a few minutes. That didn't help either. When I switch to 6-channel analog-DSP, the test tones are normal. It's only on the digital inputs that I'm getting the loud test tones. Anyone else experience anything like this?