Driving a Thiel

Hevac1, there's a difference between low range and wide range.

Cmalak,
What amp was used and would it have been able to go down to 1 ohm?
3 to 4 ohm is what Theil states their speakers low ranges are, even the 7.2 is only 2.7 ohm min.
It is a conservative estimate at best I think.
I had Theils a few years ago and found, the more power you have the better they sounded and the lower ohms the amp can handle the lower the bass would go regardless of rating.
BTW, I am not saying that Theils are not an excellent speaker. I am just saying that a quality amp with lots of power is best and a receiver will not do them justice.

Hevac1...my point is the Thiels don't dip down to 1ohm. The Stereophile measurements on the Thiel 2.4 show the min dip of 2.7ohms at 600Hz and for most of the frequency spectrum the Thiels stayed in between 3 and 4 ohms. In any case, i agree with you that the Thiels do need high quality power and a lot of it and the OPs receiver will not drive them properly. By the way, every time i check out your system, I am impressed. Nicely done.

It is NOT impedance but a combination of low impedance and a high phase angle which defines a bad load.

Even a mediocre amp will drive a resistor. Some even at 3 ohms or MAYBE even lower.
However, throw in a highly reactive load and there you go.

http://stereophile.com/standloudspeakers/243/index4.html
http://stereophile.com/floorloudspeakers/1208thi/index4.html
http://stereophile.com/floorloudspeakers/1105thiel/index4.html
http://stereophile.com/floorloudspeakers/663/index4.html

None of the above links are to the Thiel models asked about, but certainly indicate a design philosophy which requires a first rate amp which can maintain into large phase angle loads.
Good hunting.

All Thiel's respond poorly to mid-fi amplification. I know because I ran several receivers and seperates such as Carver and Adcom, searching for a low cost amp for my CS3.5s. They just don't cut it. The amps mentioned by others are no-brainers from a pure quality standpoint, but come at a steep price of entry. You will need to spend at least $600 for something worthwhile. At that price, you can get a used Odyssey Stratos. That will keep you happy for a while, no doubt about it.