Chroma, although you appear to appreciate a dulled down high frequency type speaker (perhaps you have sensitive hearing), are you sure that the mere description "metal tweeter" doesn't bring in a bias to your mind that it will automatically sound "tinny"?
I ranted about this the other day... human perception and description based on predisposition from either rumour or imagination (also known as 'bias').
In any event, you found speakers that you seem to enjoy, so that's great.
I found my M60s to be 'bright' when i first bought them and now appreciate their level of clarity in the high frequency range. I could also say the same thing about the M22s i auditioned.
However, i CANNOT say that i ever found the QS8s to have a similar level of brightness, but this is most likely because they are not the primary speaker and hence your ears do not focus on them nearly as much.
