Thiel Owners

good job MA.   keep us in the loop

espirits4s - I cannot address more than the CSi, since I have no personal experience with the CS7.2 or your particular amp. But that amp doubles twice to 1400 wpc into 2 ohms, implying that it should do fine into the 1.2 ohm load at 10 hz. The 7.2 has the opposite characteristic, a rising impedance going low, so a long cable run would act differently between the 2 models. But, it seems far-fetched to me that an amp or cable interaction would be responsible for a significant bass difference. 

I have considerable experience (in the day) with the CS5 - and I wouldn't call it bass-shy with a good amp - which you have. So, I would look for a speaker problem. First-off you can test viability and polarity of all the drivers with a single 6-volt lantern battery rigged for intermittent contact to the input terminals. Plus to red should make all drivers push out - a second or two won't hurt the drivers.  A dead or reversed-polarity driver would make trouble. The lowest and upper 8" woofers are the subs which would reduce bass power without affecting tonal balance noticeably. Please report your driver test as a base-line.
Tom

Thank you Tom.  I will start there.

Esprit4s,
i am powering CS