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.
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.
It's very possible that the posters above are correct, you might need a bigger amp capable of dealing with the 7.2's 3 Ohm load if you want or need higher peak volume in your room. It's very possible that you just got unlucky and a less than perfect driver squeezed through and just gave in. Or all or none of the above.
Heres hoping its just a driver issue.
I own the Thiel CS 6 driven by a stereo Bryston 14BSST 600 watts into 8 ohms. And 900 watts into 4 ohms. The Thiels like a lot of current before it can sound good. I have a medium size room and normally play at medium volume. Although I've never had any tweeter problem I am careful not to overdrive my speakers. The Art Pepper meets the rhythm section is quite dynamic. When played at a slightly louder than normal setting there is quite a lot of current going to the tweeter because Thiel runs their drivers with a 6 db crossover. Most manufacturers use a 12 db crossover or higher. I believe the cause of the tweeter failure is too much current going to the tweeter. The tweeter's voice coil is quite thin and cannot tolerate too much current going to it. I am interested to hear what findings if any that Thiel's find about the blown tweeter.
What big Krells are you talking about? I used to own JC-1 that sounded fine, but not great. I also had a pair of BEL 1001 mono blocks that sounded great, but the Lamm 2.1 is the best. Well, now I am re-thinking about this and may need to change amps. I will report what Thiel is going to say.
FWIW, I tend to agree with Tom. IMHO, the Krells are hard to beat on Thiels. BTW, I run Threshold with my (older)Thiels.
I am using the FPB 650M monoblocks. But someday when my wallet is fatter, I am going to go with the 750 cxm monoblocks. :)
Whats funny is I had never been a big fan of the Krell amps until I heard them with the Thiels.
90 db SPL should be ok - but some music is extremely dynamic and you may not be seeing it on an SPL meter.
Bass heavy material (while not loud) can cause an amplifier to easily run out of juice and clip....the clipping heats up voice coils and of course the wee VC in the tweeter goes first.
If you like to play music really loud then you are probably exceeding what this speaker was designed to do. It is a particularly difficult low impedance load to drive - so you need to expect troubles if you really push your amp. An easier load would be more amenable to being driven hard. Some speaker drivers are also designed to hold up better to being abused.
I don't think 90 dB should be any problem at all for Thiel's previous top of the line, that is with appropriate amplification of course.
Sounds like a driver problem to me, I don't want to jinx myself but I drove my 3.6 with 200 watt classe power for years and it could get congested when cranked on dynamic music. Macintosh 501 mono's made this a different speaker!
However, unless you play really loud more frequently than not...I mean party loud you should have enough power with your lamms IMO.
I am not a fan of Krell at all. I guess I may try a big Krell some day when an opportunity comes up. Not to offend anyone, my past experience with Krell (older models) was that they sounded whitish or bleached. Don't know about the newer Krell sound though. The Lamm has a very nice balanced and rich sound.
I have been playing at around 90 db for the past two years without any problem. I hope it was the tweeter's fault. I will report as soon as I hear from Thiel, possibly some time next week since this is a long weekend. Stay tuned.
My tweeter has been repaired free of charge. Gary Dayton from Thiel told me that the tweeter's moving part failed. My amps didn't burn the tweeter. That is why they didn't charge me for the repair. Now I am in business. Thiel's customer support is excellent and Gary was extremely professional and helpful.
Glad it was not the amps, and you are are back to listening to music. I have also had nothing but the best service from Gary and Thiel.
Thiel is the best for standing behind their products! Regardless of what else is out there, because of my 20 years of expereince with Thiel's stellar customer service, I'll always give Thiel a better than equal chance of getting my hard earned money.
I also sent a "thank you" email to Kathy Gornik, President of Thiel about the excellent customer support I received and asked her when Jim Thiel would come out with a new flagship speaker system to replace the legendary CS7.2. She said Jim was not working on the 7.2 replacement at this moment since he was busy with other projects. I really wish Jim created a new flagship at a killer price.
If and when its released. That will be the speaker I get to replace my 7.2s.