Amongst the most reliable and easy to drive of all Thiels. They do best with the typical Thiel recommended spacing. Though techincally amongst the easiest of all Thiels to drive, in practice it's a bit more challanging. Anything bright before them will be exposed, on the other hand the ported bass, though overall quite respectable, can be a bit soft. With their 6 Ohm nominal / 5 Ohm mimimum 88 dB sensitivity they are not as current/power hungry as most other Thiels. They work best with amps with tight bass and soft highs and IMHO with mid hall perspective. That's not as easily found as might be expected, especially on the cheap. Still high quality amps can be found reasonably. Though they can work with modestly powered 50-100 Watt p/c amps, they will demonstrate the benefits of added power up towards 250-300 Watts p/c. This might have been the Thiel speakers that had the most tube amp users. Despite many auditions I never felt that tubes did the bass right with them.YMMV!