Thiel Owners

Note that the 1.5 drivers were entirely developed by Thiel in-house

OK, I see.  I just thought they did look similar to some of the Vifa drivers.

I have an eccentric theory about why phase-coherent x time coincident speakers are "harder" to drive

I also notice that if I disconnect the tweeter, the sound becomes subjective less "dynamic".  I also notice that higher order filter speakers do have more perceived "slam" vs. first order filter speakers as if the drums become more "dynamic".  It may have to do with how high frequency affects our listening.  

But then beyond this, I am just guessing ...

There is a real limitation to dynamics in first order filters. On the one hand, there is no time smear or phase rotation in the crossover range for very realistic immediacy, but on the other hand, the drivers, especially the tweeter, do more work, generate more heat, and experience anomalies coupling to the air beyond their 'natural range'. Thiels are actually small-signal machines which do pretty well in normal rooms at normal volumes. But they are not and were not intended to be screamers.

You are on to something. I always notice more edge on higher order filters, which can be perceived as greater snap and slam. We had a drum kit and xylophone in the listening room at the original farm house. I vote that the first order filters sound much more like real drums and percussion. That direct comparison helped form our decision to go first order.

Guys i've been asked if Mark Levinson 27.5 stereo amp can drive the CS 3.7s properly.Does anyone know this amp ?

Not seen a Levinson 27.5 in recent times but can tell you I help deliver many moons ago Levinson amps with Thiels.  Should have no trouble driving them.  If one is in a large room and listens very loudly that is not to say that something that delivers more power can be more appropriate for them (but don't be fooled by the conservative power ratings.  Old Levinson 33Hs (helped deliver a pair of those - came with a free hernia - 220 lbs. each shipped with the crate), could drive just about anything (at least what I've seen and they didn't have excessive power ratings vs. many other things - very conservative).  With my old Thiel 7.2s (which are a harder load that the 3.7s), I did own Proceed amps (which were basically Levinson budget amps). and they drove them no problem.

@cascadesphil thanks for your feedback, yes the 27.5 doubles it's power from 8 to 4 ohms even if it's ont 100w it must have quite a bit of current.This guys who owns this Levinson 27.5 is interested in buying my 3.7s.