Fixing a troubled speaker and thermal considerations

[scott_jcp]

I built myself a BrianGT LM3886 gainclone (stereo with a single PSU and around 34 volt rails), which I heatsinked by thermal pasting and bolting the chips to the just under 1/8" thick aluminum/zinc sheet metal that formed the base of my case. While using the amp, I have fairly frequently triggered the thermal cutoff of the chips. While I am adding heatsinks to the chips tomorrow, I think I might have caused permanent damage to my speakers . I don't think I have been clipping my amp (because the thermal cutoff won't let me turn it up very much), but my speakers are rated 100W (versus the 56 or so my amp will put out), so I might have been. Would driving my amp into thermal shutdown repeatedly generate significant amounts of distortion? The reason I think I have damaged my speaker is that one of my tweeters now pops quite audibly occasionally (though it otherwise sounds perfect). Is there a way I can fix this popping? In my car I once drove my speakers to high and got a crackle that went away after playing the speakers at a low volume for a while. Will something similar work for this tweeter?

Thanks,
Scott