Blown CS7.2 Tweeter/midrange

90 db peaks is not overly loud in my opinion. The fact that you blew a tweater at this level is in my mind an indication that there is something wrong somewhere. This assumes that your amps are good amplifiers and not clipping when driving these Thiels to this level. These are a fairly power hungry speaker and I am suspicious of any "mass market" power amp's actual capabilities vs. rated. Not knowing your specific brand and model of amp, it would be hard to say. However, in reading your statement, you claim the amps are 200 WPC @ 4 ohms (which according to many manufacturers that means they are 100 wpc @ 8 ohms). If this is a high current amp, such as most of the Krells for example, then I would find this surprising. However, there are quite a few brands that I would not trust to drive this particular speaker at the rated output without clipping.

If you are pushing your amp too hard, this increases the potential to damage your speakers. If you review the threads on the Thiel speakers, I think you will find that most owners recommend feeding these speakers a lot of good class A power to drive them successfully. Personally, I would not even consider running these speakers without an absolute minimum of 200 WPC @ 8 ohms of high current, class A power and would prefer to have at least 300 watts @ 8 ohms.

Perhaps Thiel will be able to find something wrong with the tweeter itself which contributed to the failure.

Ckoffend,
I agree with you. It could be the amps. However, the amps I am using is a pair of Lamm 2.1 mono blocks that I trust. They are rated 200 watts at either 4 or 8 ohms. It has a switch at the back to select the ohm setting. It is class A up to about 36 watts, then AB above 36 watts. I would think the amps should be adequate. I have this amps and speaker combo for a year without any problem until last Sunday when the tweeter blew. I have yet to hear from Thiel about the cause of the tweeter failure.

In fact, I played louder than 90 db before on some occasions with ultra dynamic classical music. I was just playing the first cut of side one of Art Pepper "Meet the Rhythm Section" 33 rpm by Analog Production when the tweeter failed.

That said, 300 watts could be a better match with more power as reserve.

Judging from what I have used with my thiels i would think you need more amp. even when using my Ayre V-1XE it became compressed at times when driven loud and was always running very hot trying to push the Thiels. it is rated at 200/8 and 400/4. I also noticed the Parasound JC-1s I used with mine never really took hold of the speakers the way they did with other speakers I used them with. I am using big Krells now and, WOW! I also tried the big Pass amps and thought they did a good job but preffer the sound of the Krells.