Thiel Owners

@jon_5912, I’m glad you’re enjoying your CS 3.7’s. Good news!; I’m confident you'll appreciate them even more with a better source:

https://www.noteburner.com/youtube-music-tips/youtube-music-audio-quality.html#:~:text=To%20put%20it%20simply,%20it%20depends%20on%20whether%20you’re%20a

@tomthiel, I might be a bit concerned about using tilt down. First from a balance perspective, might be precarious around toddlers and pets. And then there might be a concern with floor sound bounce and perhaps over emphasis of sonic boundary reinforcement?

Thiel CS1.6 loudspeaker Specifications | Stereophile.com

Thiel CS1.6 loudspeaker Measurements | Stereophile.com

Thiel CS2.4 loudspeaker Specifications | Stereophile.com

Thiel CS2.4 loudspeaker Measurements | Stereophile.com

THIEL CS2.4SE Floorstanding Loudspeakers With only 150 sets made, those who buy a pair are very lucky. Review By Tom Lyle

Specifications - Thiel Coherent Source CS2.7 Owner’s Information [Page 10] | ManualsLib

Thiel CS3.7 loudspeaker Specifications | Stereophile.com

Thiel CS3.7 loudspeaker Measurements | Stereophile.com

FWIW, except for some of the PS Audio gear which aren’t pure tube products and as evidenced in the footnote during independent testing struggled with sub 4 Ohm loads, none of the forementioned tube products are actually spec’d to deal with the forementioned Thiel loudspeakers actual impedance load. We could do this again with also previously attested to ss amp, but as ss amps are much more likely to be able to produce the current needed to double power output with halving  of impedance (which also decreases the spec’d speaker sensisitvity by 3 dB for each halving) unlike most typical tube amps which do not.

Aesthetix : Products : Saturn and Jupiter Series

Audio Research | Product Range – Audio Research

Balanced Audio Technology *1

Products | Cary Audio

current conrad-johnson products - conrad-johnson

All Products – PS Audio

Rogue Home Page

*1 PS Audio BHK Signature 300 monoblock power amplifier Measurements | Stereophile.com

From what I understand the the most common and most troubling service compalints regarding audio equipment is subwoofers, and in particular those that are self amplified. Often these subwoofers use propriertery and perhaps worse limited production runs of DSP modules and Class D amps that become unserviseable and irreplaceable. 

@ig316b, A pair of subs that are well implemented would certainly help those speakers particularly in the bass region, but it will be nearly impossible to totally eliminate  a delay in a portion of the frequency response. No, you will not get the ultimate cohesive sound that sealed boxes like the CS 5’s provide.

@wisinskt , Can you rip from the Oppo to Roon with this mod?

@tomthiel  Thanks for the tip re: tilt back and toe in ( or the lack there of ).

I hope you’ll indulge me if I return to the subject of placing identical Thiels back to back; what might be a typical minimum distance from the rear firing speakers towards the front wall as seen from the listening position?

@largeexpensiveboxes , for the CS 6's look for amplification capable of a minimum of 400 Watts into 2 Ohms. Depending on your room and desired listening levels more power could be beneficial. For most people in most rooms 800 Watts into 2 Ohms would be satisfactory. The important thing to look for in making a short list of potential amplification considerations is to consider power into the the actual load demands. The CS 6's impedance is much more demanding than the CS 2's. That 2 Ohm capability is key, from there system compatibility and personal sonic preferences can be used.

Hello, to all here on this thread. I want to give a shout out to @Duramax747. Heed his advice; as it is without doubt some of the best posted here!

@ig316b , That’s a bit of an open ended question?

Not all subwoofers are the same. Amongst other things, many subwoofers are ported as well.

Ported speakers have the advantage of providing more bass in a smaller box and/or more efficiently. However if one is pursuing more accurate bass, especially if time coherence is an objective ports, slots, passive radiators, etc., are a compromise. With the first order 6 dB slope used in most time coherent designs exacerbates this. With that said it’s quite remarkable that Jim was able to make ported bass speakers as well as most anyone at their price points and above, even compared to designs without time coherence objectives using more forgiving cross overs.

Still my preference is, for amongst other things: sealed boxes.  In the past blending subs with main monitors was problematic.Things have advanced, and it’s much more likely to succeed in satisfactory blending today. IMHO, ports and their ilk as a design principle, should only be considered when space and/or finances are more limited.

At the risk of appearing pedantic, If one were to mate sealed boxed subwoofers to sealed boxed monitors, and with perhaps some DSP one might achieve equal time coherence to that of a full range time coherent speaker. 

One caveat is that the subwoofers might have to work further up the frequency range (an area in which they become progessively more clumsy) to augemnt the the lessened upper bass output of the sealed box monitors (compared to typical ported monitors).

On the other hand there could be advantages in room placement and specific power requirements to such a pairing, Though not without added complexitiy. 

Getting such a system to work cohesively is not trivial endeavor

Addendum: The above presumes that the sealed box monitors are themselves time coherent and the use of the appropriate crossover to sealed boxes subwoofers are used

Ultimately it is the ports that are the obstacle towards true time coherence.

@ig316b, As best as I can remember at least some of the SCS’s came with port plugs. I’m not sure if those models were optimized for use with or without. Often times used models are missing them. I don’t remember if the port plugs were offered for the PCS’s. I believe the earlier SCS’s came with 2’nd order crossover which are not as time coherent as Thiel’s models’ that featured 1st  order crossovers. Generally the lower the monitors go; the better. Keep in mind there are other parameters considered when designing between ported and sealed boxes.
 

@jwei  Bass in rooms can be problematic. Room treatment for bass issues can be cumbersome. Reducing reliance on room treatment can be less expensive, and less intrusive. I suspect placing the subwoofers for the best room fit first, and then dealing with the spacing / time alignment with the appropriate monitors with now less intrusive DSP might be  best.

@spacebird42 , The CS 1.2’s  with their moderate sensitivity and perhaps more importantly above 4 Ohm impedance they are amongst the easier Thiels to power. They can not go very low in bass , play very loud l, aren’t meant for large rooms. So used as intended they aren’t that power hungry. Due to their lack of low bass they can sound a bit tipped up. Avoid amplification that’s on the bright side, has mid-range suck out or is loose in bass. If you can find an old ss conrad-Johnson MF-80 that has been recently re-capped; I think you will be very happy.   BTW, used alpha-core MI 2 speaker cables are a relatively inexpensive choice that will work beautifully in such a system.

@guy48065 Old technology now. When you think about it, it’s not much different than how the RIAA curve in vinyl tampers with the signal or crossovers slice up the frequencies in the analog domain. As bass frequencies are the least beamy and more omnidirectional it makes the most sense to use DSP there. Such use could also lend itself to the use of. “SWARM” multi sub use to even out room peaks and dips. 
I will say that to my ears bass is more directional than the theory would suggest. And the simple elegance of full range loudspeakers is most appealing.

@tomthiel , I do this with some apprehension, but as you say "Since this is all water long under the bridge,..." When Thiel Audio was still in business, but suspicions of Jim’s health concerns were begining to be rumoured, a reliable source (who out of respect will remain anonymous) at Thiel swore me to secrecy to share that Jim was indeed considering an all-out Thiel with a price point much beyond Thiel’s previous offerings that would feature an omni-directional design.

I thought this might be of some interest to followers of this thread, though this paper is nearly 10 years old, it just recently came to my attention:

https://www.keele-omholt-technologies.com/papers/Keele-CBT-Paper-08-Oct.-2015-Time-Phase-Behavior-of-CBT-Arrays.pdf

for those that want to take a deeper dive into the subject:

https://www.keele-omholt-technologies.com/papers.php

more discussion:

https://www.audiosciencereview.com/forum/index.php?threads/constant-beamwidth-transducer-cbt-speakers.12060/

“Listening to a sealed speaker you hear the bass in real time and it’s difficult to go back.” I very much agree!

@andy2 , I agree with @jafant in that  often times it's with the recording. I can't comment on your hearing. But after the recording, I suspect it's more likely room and/or placement issues rather than your gear.

@andy2, It could be due to surface area as early reflections can have an impact on sound stage and/or imaging. Room treatment might mitigate your concerns. 

@tomthiel, of course you would know better than me. But, aside from being able to make the under hung motors more available across the various models , which  is somewhat negated by the lowered price point models using different woofers anyway, I think the sealed boxes were the better choice. Other manufacturers such as Dunlavy with similar performance goals were able to do it. Though to be fair the Dunlavy’s used more drivers in bigger boxes or used acoustic floor volume reinforcement. All of which created a different set of concerns. I’m not sure all would agree, but I for one think those, and the previous use of eq were worth it.

As Tom said; ..."Consult Stereophile's review for details and considerations."...

Thiel CS1.6 loudspeaker Measurements | Stereophile.com

The high sensitivity might be misleading considering the below 4 Ohm impedance, and the somewhat recactive load.

The NAD C375 BEEis is spec'd as >150 Watts 8 and 4 Ohms. As is is not spec'd to increase steady power with impedance drop suggests current limiting. It does suggest good dynamic power down to 2 Ohms, But as seen in the link above the CS 1.6's are below 4 Ohms a good deal of the time. I think the steady state power output into impedance is more relevant.

User manual NAD C 375BEE (English - 18 pages)

As 3 Ohm ratings are not typical (only the stereo version of the Benchmark jumps to mind), I think it prudent to consider the more typical 2 Ohm ratings when they can be found. A minimum of 200 Watts into 2 Ohms should be considered, and personally would use at least twice that. As @duramax747 wisely suggests YMMV.

@johnnotkathi,

 Take this with a grain of salt.

Jim Thiel thought Class D amps were only suitable for sub-woofer duty. But a lot of progress has been made with Class D since Jim's passing. 

I haven't experienced these for myself.

Before considering those older amps that might need to refreshed with new caps, etc., which if you don't have the where with all to do yourself could end up costing as much as the current purchase prices..

FWIW, I would consider the offerings from:

Buckeye Amps

Though there is a 10% restocking fee for non-faulty returns, I think these might actually be better performing with less risk for less money.

FWIW, the SINAD measurements would suggest otherwise. Not all switch-mode power supplies are the same. At the $1K (and perhaps even more) is a compelling consideration.

@johnnotkathi,

Thank you for saving me from having to reply.

For those who might eschew the objective, and might prefer the subjective;

i suggest comparing the output with one’s ear in direct proximity of a loudspeakers drivers with source turned off: with most of the better new Class D amps compared to traditional  Class A or AB amps. I think most will typically find these  Class D amps to be quieter. I’m not suggesting the SINAD is the be all/ end all, but it is a measure of noise (and distortion) after all.

@audiofilio123,  Respectfully; if you subtract all the marketing fluff, those specs aren’t all that special.

@77jovian ,

Thiel CS2 2 loudspeaker Measurements | Stereophile.com

Ayre Acoustics AX-5 integrated amplifier Measurements | Stereophile.com

Unlike some other Thiel models the CS 2.2's only have a somewhat small and fairly brief dip below 4 Ohms While the Ayre is not actually spec'd to deal with the Thiel CS 2.2's, and FWIW wouldn't be my choice to power them; depending of course on your room and desired volume levels I think you'll  find the AX- 20 adequate.

@biannuzzi22 

Contact - Coherent Source Service

I was wondering if anyone here has tried using two pairs of identical Thiels set up up with one pair back to back with the forward to the listener pair? If so, how did you set it up? How far from the back facing pair were they from the the wall they faced? Where they wired in phase (bi-polar) or out of phase (di-polar) from the forward to the listener pair? What did you notice? What did you prefer? Would you reccomend it?

@brunner007, While perhaps not addressing you immediate question; the Threshold SA/2’s while very lovely amps with good current delivery into impedance, I think the Threshold SA/ 2’s have about the bare minimum power output needed for some of the Thiel’s you’re considering. Perhaps you might consider more powerful amps, especially if you’re considering a larger room.

@wisinskt , Perhaps, I’m mistaken but I seem to recall that respected forum contributor @duramax747 with his somewhat unique professional skills was working on a similar project.

 Keep in mind that depending on one’s room and in particular that rooms flooring, and depending how these devices are coupled or as the case may be decoupled, can make things sound just as easily worse or better. YMMV!

@tomthiel, I find your plan to have “outriggers “ also act as a place holder for outboard cross-overs both clever and compelling. I look forward to design completion and availability.

I guess a couple of degrees will be inconsequential.

I hope the forum will forgive me for going off “Thiel” topic, but @wisinskt could you elaborate on your Oppo is2 board mod to Roon?

@wisinskt , I’m led to believe that while that might be possible with the Oppo 100 series Oppo’s, it’s not possible with the later (last) Oppo 200 series .