Thiel Owners

Unfortunately there is only a high-pass filter so I can’t experiment with that.

Have you tried the experiment of unplugging the subwoofer? The Stereophile review of the CS2 points out that the 42Hz extension is adequate for most rock music. And your system making you nauseous is pretty much the opposite of enjoying your favorite music.
https://www.stereophile.com/floorloudspeakers/1085thiel/index.html

I have definitely unplugged it for now! I can consider keeping it without a sub. But I did notice something lacking while watching a movie the other night. Any sci fi movie with a deep music track will make me want more bass. I also listen to hip hop and trap music. Those sound really great and clean without the sub, but there is a something missing. And even orchestral music, which is the main thing I listen to, sometimes feels like it could benefit from a little bit of something at the bass end. Maybe a smaller or less powerful subwoofer would do the job better?

A room that is 30' will have a resonance at 37.5 hz I think.  (speed of sound is 1,125 ft/sec, 1,125ft/37.5 = 30 so a 37.5hz wave has length 30')  It might be that by extending your response just a little bit below that of the main speakers you're exciting that node a whole lot more.  I have a similar situation in a big open family room/dining room area.  I've found that by equalizing the peaks down 3-4db the problem becomes much less audible.  Too large of a cut and the frequency response is technically better but sounds worse to me.  

brayeagle

This one is for you my Audiophile friend. Thank You for hanging in there with me.  Earlier, on this beautiful sunny day here in Atlanta, I enjoyed a very nice hour drive north of the perimeter (the weather here has been very wet and soggy for months).
Around the Lanier Lake area I found myself visiting Mr. Michael Burns-owner of- Wolfsong Audio. He is a very pleasant Gentleman of Audio and runs his operation from personal residence. He is a prior CS 2.4 owner. His sound room is beautiful and well damped. I was in luck because he is a Ryan Speaker dealer/retailer as well as Bryston and a few others. We listened to a 4B3 power amp, BP-26 pre-amp/separate power source, BDA3 DAC, BDP Pi, Blue Sound 2 device fed into Roon/Tidal, Proceed CD Transport, DH Labs cabling and Ryan R630/Bryston Model T Signature w/ outboard cross-over network. As always, the session began with Jamie Cullum "Twentysomething" CD. The session also began with Bryston Model T Signature loudspeaker. This is a large floorstander which throws a large presentation, lateral soundstage. To date, I have not heard nor seen a loudspeaker that features an outboard crossover- very cool design.
Jamie's piano and organ sounded very fine without any congestion throughout midrange registers. Bass output was solid.   Next, Bryston was swapped for the Ryan Speaker. 
Smaller in driver array and size,  this speaker presented in a more audiophile tradition. Better imaging and soundstage depth was experienced. As Michael and I were talking between numbers, we believe that this model has a 1st order crossover within its design. Tweeter and midrange sure sounded like a time-phase coherent or transmission-line design.  Bass was articulate and clean but output not as low as the Model T Signature (3 larger Bass drivers per speaker).  More selections were aurally pleasing from The Police, Natalie Merchant, Pearl Jam, Michael Hedges, Pink Floyd, James Maynard Keenan, Helmet and The Rolling Stones. 
Referring back into my sonic memory, thinking about the 4B-SST/SST2 series, I would say that the next generation Cubed series has a measure more  warmth along the lines of Pass Labs. For those who felt the older Bryston amps were bright dry or harsh, will be pleasantly surprised in the 4B3. Anemic, clinical nor thin sounding was not appreciated. Talking about the BP-26 preamp which has been around for 10 years now, it still features a lower noise floor than a BP-17 Cubed. A benefit for Vinyl lovers. 
While considering this combo, my search for a reference CD/SACD spinner carries on.  It would have been nice for Bryston to build/design SACD playback capability into their reference BCD-3 player.  In closing, a perfect Spring-like afternoon, good company/ fellowship and very good music.  As soon as I find my spinner, I will follow up with Michael for a second Bryston demo.
Happy Listening!

jayant

Many Thanks for the recount of your visit with Michael Burns, and of your impression of the Bryston 4Bc amplifier. It correlates with the views of other individuals whom I trust in the music reproduction arena. I don't have unlimited resources, so springing for the 4Bc is not a trivial expense. I've been living with my 4BSST2 for some years, and I guess that familiarity might have influenced my "hearing"concepts. I guess I'm ready to take the plunge and retire the 4BSST2 for a new 4Bc. 
I listen to classical music almost exclusively - - symphonies, chorales, concertos, operas, string trios/quartets and organ. I'm not a bass addict, but want it reproduced in context of what's in the score and has been recorded.
I was able to get a BP-26 and power supply, as I'm putting together a system for my son. So, Ive had the opportunity to directly compare the 26 and the 17c for about a month.  I've listened to both preamps in my system and, all things considered, now prefer the 17c over the 26.  IMO, the 17 doesn't have the somewhat pronounced mid-bass of the 26, and it has a much clearer and smoother treble - - especially with tenor, alto and soprano voices. It's also is less "dense" in the mid and lower ranges. The sources of the music for this evaluation  were my  CDs, played on a Bryston  BCD-3 spinner, through my 2.7 speakers, driven by the 4BST2. Also,I've listened to both preamps with my STAX  Lambda Pro headphones.
I'm certainly not in a position to judge the noise floors on each, so I'll   depend on the knowledge of others, especially if phono preamps are in the system. 
Hope you'll be able to find a CD/SACD spinner that will be what you desire. In the long run, I believe CDs and SACDs will complement streaming as a medium. For simplicity and choice, if for no other reasons.
BTW: My family came from Savanna and Charleston, but migrated to Thomasville. So, now living in Northern Virginia,  I'm jealous of your nice  Atlanta area weather!