Such a simple sounding question, oiy vey. I've owned Thiel 2.2, 2.3, 3.6 and Proac 2.5 and currently Spendor FL-9. Here goes....
1. Thiel sound vs Proac vs Spendor
Thiel are very clean and analytical. They need a lot of power to sound their best, especially the 3.6. Proac is more naturally musical but slightly less neutral and detailed. Spendor is even a bit less neutral and detailed, but to me the most musical. One could argue that Thiels are missing some of the naturalness of the music, or, that the Thiels are fine but the components or recordings are the problem. Sigh.
2 Some people prefer Thiel 2.2 over 2.3. Not me. I think the 2.3 is far preferable to the 2.2. It is more extended on top and bottom and astoundingly coherent top to bottom. It is more coherent than the 3.6. 3.6 has far more bass energy though, when properly powered. (400wpc solid state) 2.2 vs 2.3 appears to be a matter of taste since opinions do differ on this.
3. A LOT of breakin is needed for all of these speakers. Just playing them for a hundred hours is not enough. I discovered that a quick breakin is possible, by placing the speakers face to face and reversing the leads on one speaker. They will play out of phase with each other and the midrange and bass information cancel out, while the drivers are working hard. You can play speakers loud in this configuration and hear almost nothing. You can also destroy your speakers if you are not careful.... but when done carefully, you can achieve extraordinary breakin, really, years of breakin, over several nights of quiet play.
Many, perhaps most of the complaints about all of these speakers look to me to be attributable to lack of break-in or, in the case of Thiel, under-powered.
4. Cables matter. Quality of gear matters. A lot.
Art
ps have any of you heard the new Thiel 1.6?
