Thiel Owners

@bighempin:  If you are ever in Atlanta you are more than welcome to listen to my 2.4's on my Pass Labs (power amp) / Aesthetix Calypso/Janus preamp system.  Amplification is tremendously important especially with the Thiels which are a bit finicky.  I also like the PS Audio gear (I have their Directstream as my dac).  Let me know if you're in town and interested and we'll set it up.

Tomthiel,
thanks for your advice.
I am using Bryston 7b monoblocks.
i don’t think power is the problem but I will change the Parallel/series mode setting so they double down in the 2ohm loads.  will let you know if that changes anything. Then I’ll pull them out when my wife is not home just to hear what happens. You are asking for a lot - 5ft!! 
Jafant,
rest of my system is OPPO 105d, Technics SL-1600MKII with Shure V15 cartridge, Bryston BP20 preamp, Monster HTS3600 power center, Grover Huffman Empress silver speaker cables and Siltech connects.  Most of my listening is streaming through Tidal.

i will say this: I am pleased the speakers sound great even at low volume. That was one of the glaring shortcomings in my previous speakers, Egglestonworks Andra.

Jack, my first thought was what Beetle suggested, but turning the room around is a very big deal, and listening from the dining room is probably a goal . . . 5' is a lot, and somewhat more than necessary, but more is better to separate the direct from reflected wavefront. But 2' is not enough. The auditory brain tries to integrate sources separated by less than a few milliseconds. We are testing.

Your equipment is great and as you say, should not be the problem. However, bridged amps are less comfortable driving low impedance loads. The 7b has huge power, so matching impedance is probably more critical than power. I don't know the circuit of that amp to make a recommendation. Experiment and let us know.

I do know that my first approach to upgrading the CS5 would be to separate the bass drivers (3x 8" on 2 bass circuits) from the uppers with 4 identical amp channels running the pair of speakers. At the 400 Hz lower midrange crossing, the impedance is 4 ohms and rising slowly, which presents a sweet resistive load for the upper amp. The bass current draw would be sequestered in its own channel.

Your problem is the core problem that limited the life and acceptance of the CS5. Both at the time and more so in hindsight, I believe a 4 channel setup for the CS5 might have made it a success.

The 2.7 has a huge electrolytic cap bank to roll off the bottom of the midrange where the 8" woofer wants to cross in.

Hi Tom,

Out of curiosity, since the 3.7 and 2.7 share the same midrange/tweeter driver, wouldn't the 3.7 should also has a large capacitor bank as well?  My guess is the need for a large cap bank because the xover freq. is rather low - probably aroud 200 - 300Hz to the bass driver on both speakers.

In a typical speaker if crossing over at 200Hz is required, the amount of cap is probably around 80uF to 100uF depending on various parameters.
I could see the use of electrolytic since using poly cap could be expensive if 100uF is needed.

Andy - same coax but higher crosspoint to the 8" 2.7 woofer requiring 416uF series blocks. 400uF electro + 15 PP + 1uF styrene / tin foil. The lower 3.7 crosspoint needs 226uF as 3x75uF PPs plus the 1uF S/T. ( no Es in the 3.7 signal path.)

As I've mentioned before, Jim wasn't alive to apply his typical methodology, which would have been using the coax he was developing for the 7.3 to feed the 2.5 just as the 2.4 had been fed by the 7.2 and the 2.3 and CS7 were co-developed.
That jujitsu of dropping the 3.7 coax into an 8"model 2 and calling it the 2.7 is not Jim Thiel methodology, but rather a way to use an extant driver in a fall-down product, creating a model 2 more similar to the 3 in performance and cost.

You are right, big film caps are expensive. Note that the 2.4 upgrade requires only 42uF series feed caps.