Let be make sure I understand what you have, is it that you have a pair of forte II's & a pair of Chorus I's? If so your amp sees 2.67ohms (based off of advertised impedance values). BTW are you a ham? KA1J looks like you are, I am KJ4NKN General class
They're likely both toast, but just unhook a speaker and hook it up directly to the tweeter with an AVR or something, of course at a very low level.
That's a lot going on for that 275 to feed. Given a Damping factor of 22 and it really being a two channel amp, no telling how low the ohm dips are with your content, which are likely increasing the THD numbers well above where they are spec'd by the factory.
Thanks for the replies,
The amp is a McIntosh MC275 VI set to stereo (75W/ch) and has the option of driving at 4, 8 or 16 ohms. I have it in the 4 ohm position. I've never put the amp up to maximum, I'm not into pain...
With this particular equipment I can't imagine how I would have overdriven the tweeters.
Unfortunately, I threw out the original tweeters after upgrading so I don't have those to now compare with.