Thiel is officially closed!!

truthfully i am not sure.  the first time it happened i think it was just a bad driver from the outset as it happened about two months into listening.  was using a reference Marantz amp at the time. second time was using the great PS Audio BHK amp so i know it was not the amp clipping or anything.  granted i play it loud but no more so than when  i had CS2's, 2.2's(blew a midrange once in18 years),  and 2.4's (no problems).  it seems to be the midrange driver and not the tweeter that goes. hard to figure but i am more judicious these days with volume. i measure it and rarely does it get about 85 db. 

I was cranking beethoven when I blew a midrange on my 3.7s.  I also may have clipped as these are a pretty difficult load.  It happened in my first couple of months with them and no problems since.  I doubled the amp and run bridged mono now.  6-800 watts into 4 ohms.  I'm also more careful with the volume.  They play plenty loud but I will say that they were not distorting audibly when this happened so it may be that they don't give much warning before failing.

The store I bought them from said one thing that can happen is the glue between the woofer cabinet and top can dry up and fall out meaning that the air pressure in the woofer cabinet can leak into the top chamber and put pressure on the mid/tweeter.  You can push on the woofer and radiator (gently, obviously) and see if the mid moves at all.  If it does you have a leak that needs to be plugged.  Open up the top and seal up anything that might be leaking from the woofer chamber with wood glue or caulk or something. 

thank you so much.   that is great advice and i will gently push on the midrange driver.  i think the drivers are the same for the 2.7 and 3.7

I guess I have been lucky, I crank my CS6 and 3.6. Good advice on the importance of a good seal.  I do check mine periodically.

i do not think the older drivers were as vulnerable, as i have had four generations of the 2 series,  and prior to the 2.7's,  only blew one midrange one time.  Gary at Thiel said it just failed and was not caused by anything i did.