Yeah I had a similar issue with my Qs8's, and Joe convinced me to narrow it down further and I did and it was a single Qs8's bottom driver which had an offending piece of masking tape on the inside that had a corner touching the driver (which I removed and all was well). However when trying to do the same with the M80's, I swapped left for right with no difference - thus the reason I thought perhaps I damaged them with my amp somehow (unless both are bad? what are the chances, then again, with my streak...).
Tomorrow I plan on sitting down with a couple CD's that I have and see if I can narrow it down to upper or lower tweeter and pop it out and see what I can find.
-pd
