Thiel Owners

Solo, I have been using Eric Clapton, Unplugged lately. With amps, blind comparison is essential, letting my wife do the switching between amps, making sure the spl is equal.
I started on the write up and it will be a lengthy document to cover everything. Be patient and your help as a proof reader would be helpful.

Solobone, I tested the same combination of 3b-st against the par. 7b-st, thinking that more current would be making an audible difference. At the spl that I play my music 80dB, there was no difference and the actual difference in Max spl was maybe 3dB. The 3b-st are very capable at moderate volume and the needed power is modest, 30 watt according to my measurements is plenty.

On a different note, the 3.5 can be really enhanced with tri-amping. Spend this summer hundreds of hours measuring, listening and comparing, and can now comfortably say that the 3.5 are competing with the 3.7. Measurements indicate even better phase coherence with linear xo filters and the absence of any phase shift is remarkable in the clarity and definition of the sound and soundstage. Being able to dial in exactly the amount of Base that the speakers can handle without distortion is priceless. I hope to write up my journey and make it accessible to others.

McCormack is also good and in your price range. However, the power of your amp is more then adequate for your music IMHO.

ok, as promised here is my lengthy write-up of my summer project modifying my Thiel CS3.5https://drive.google.com/file/d/1A1Hs9g2tr27cGUfzSX8IcUy3dC-TpVrk/view?usp=sharing

Unsound, thanks. I'm very aware of my cautious budget choices as this was more a proof of concept exploration. What would you have done differently? We can continue this discussion by email if preferred.

Unsound, the OEM drivers are no longer available, nor can the mid-range be rebuild. Tweeters of dynaudio are still available used. The bass equaliser of the 3.5 is prone to damage from static electricity, and Rob is out of parts to repair them. Fortunately all of this can be managed with dsp and the 3.5 have a new lease on life.

Masking tape has my vote.

Jhouse, those speakers look like they have the same color as a pair that I have, and teak seems right. However the finish of your speaker is not original and will need some work to rehabilitate. Tom has probably some good suggestions what to do. 

Tell your accountant it is a business expense 😀

With both speakers it could be a room mode or other boundary effect. Test it by changing locations in the room.

Ok, let's try to keep the concepts clear. Time coherence is different from phase coherence and obtained differently. Thiel speakers are time coherent from an 8' distance as the drivers are set back in the baffle and the sound needs to travel some distance to fully integrate. In my measurements, I obtained time coherence within a few mm. at 8 ft among the drivers excluding room reflections by using freq dependent windowing.
Phase coherence in Thiel speakers is at best minimum phase, which means there is a phase shift that is measurable. The first order xo filters and the drivers have a minimum phase effect. This minimum phase effect can be reduced with dsp and other cancellation methods and linear phase can be approached above 100 hz. As Tom has warned, the preringing can become an audible problem so pick your imperfection.
Andy, if your point is that all speakers have some phase shift dependent on the frequency, there is argument. Thiel specifies it to be within 14 degrees which is considerably better then most alternatives. With dsp, the phase shift can be further improved if desired at the expense of potential preringing, although this effect can be mitigated to some degree with additional filters.

The reviews on audio science review forum suggest some caution with the audio-gd dacs.

Let me add my impressions to the comparison of the 7.0 and 7.2. we listened to some Michael Jackson songs from thriller album. Rob has all Bryston, the latest CD, pre amp and 28 B3 amps. Not sure about cables. As the room is an office, perhaps 14 x 16 ft without any room treatment, it is fairly alive. Listening to both the 7 sand 7.2, at 85 to 95 dB the immediate impression is the excellent bottom and bass response. Hard to pick a winner as both were astounding. The mid and high is where we there is a difference. The 7.2 is more resolving and given the acoustics more intrusive in the highs whereas the 7 was more balanced all around. When I came home and compared the same music on my 3.5 and 3.7 I would say that the 3.5 has the same character of the 7 but can't compete at the higher spl. The 3.7 can't match the 7 or 7.2 in the bass but easily makes up for it in the mid and highs where the resolution, clarity and balance is unmatched. If anything, how all of these speakers have a great soundstage and draw you into the music makes you forget that the are these differences. I would say love the speakers you have and make them work the best with what you have as far as room and other components.

With all these variables related to parts of a passive xo, any experience how a passive xo compares to a digital active xo? Maybe I should hook up my passive xo again.

Andy2, glad to see that more people are getting familiar with options to have linear phase. The steepness of the slope had an impact on the pre ringing, as has the frequency of the filter. As the goal is to keep the pre ringing inaudible, lower order XO are better, especially for the bass to mid XO. For the mid to tweet xo, the frequency range of the drivers and distortion may determine the preference for the XO order. As the timing can be measured and adjusted for each driver separately, the time coherence can be obtained at the listeners position easily. 

Andy, what you call more natural maybe related to the lack of frequency dependent phase shift. Your mind will need measurements to make sense of this. Simulations are no substitute. Don't under estimate the skill of making accurate measurements, I'm still improving in that area.

Had both a pair of svs pb 12 and sb12 on trial. Likely will end up keeping all of them.

Beats having nightmares

I'm exploring adding woofers to my system. I have a large listening space, 30x30x20 ft where I have my 3.7 positioned. Have the svs sb12 and pb12 on trial. Have a second listening space of 22x16x12 where I have my 3.5. Tell me about your experience, placement, cut off setting and anything else. Thanks

Thanks Tom. Yes, I was thinking to use 2 sealed subs with the 3.5. 

Happy to report a noticeable improvement with the subs and the 3.7. The modes in the room have now been tamed resulting in more relaxed and balanced sound, more enveloping especially listening to orchestral pieces, and the speakers have now completely disappeared. Soundstage is now massive, much easier to listen to lower volume and get the full experience. Have the subs located halfway on each sidewall, 18 inches off the floor. 

Great posts. Just got lost with this statement. Not sure if there is a typo:
The CS3.5's equalizer was a gigantic improvement, which I found to sound just as good as no eq at all.

Thanks for putting this in words. I fully concur with your observations. Even though some improvement of the speakers is audible, I get the biggest improvement from the improved room response from experimenting and simulating with different placements. 

It is nice to imagine innovations to the Thiel speakers but to really make this happen will take a considerable investment. I'm curious how many of us have resources to share to assist Tom in his pursuit and would be able to commit to make this a success. Tom is not immortal and will need support and cheering if not some simple help to verify the accuracy of his observations. I am very willing to contribute to such an initiative and am wondering if there are others. You can privately contact me if you prefer.

I had the 3.5 and got last year the 3.7. I can argue both ways: the mid and highs of the 3.7 are superb, but the bass and extended bass can be improved with subs. They're improvements that shine in a large room. Now, it all depends on the room. If your 3.6 work for your space and more importantly, you have learned to like them for what they are, and all the drivers and xo are good, any change to a 5,6,7 or 3.7 will involve a trade off. Proceed with caution, and clarify your goals depending on your situation. By tailoring my 3.5 by going with tri amping, replacing some drivers and carefully applying dsp, I was able to approach the listening experience of the 3.7 using the 3.5 in the space they were located.

Brayeagle, have to admit that my subwoofers fixed any bass deficiencies of my 3.7. current measurements show bass extension down in the teens. 

Although the Thiel subs are great, I decided not to go this route as Rob warned me that he can't service these build in amps. When they malfunction, you are stuck. 

Prof   I don't find myself pining for more bass either with the Thiels or the Josephs.
Your experiences may be different but for me the subs really add something that I don't realize until it is not there. It is not so much more bass but clearly hearing the foundation of the song. Once dialed in, there is no going back. Now, if you switch out speakers regularly, it may be inconvenient to go through the trouble. For my large room, the subs were easily integrated, but for my smaller room, I'm still experimenting with determining the best positioning. 

At audiosciencereviews.com amirm has now a top of the line Kippel measurement set up that produces spinorama graphs that correlate .86 with user satisfaction of speakers. Would be nice if someone from the Seattle area could let him take some measurements of a Thiel speaker.

Bluestone, I'm curious about your experiences with different mid range drivers and also with these vintage amplifiers. Keep sharing. Thanks

Sounds like the collection that came from the Thiel museum when thiel went under.

I believe that it is the opposite. One ahb2 works fine but the mono. Ahb2 has a higher impedance and won't work. Check with benchmark.

Tom, with a tri amp setup, do you hear other benefits besides better matching of the amp to the driver?
Regarding amp preferences for the 3.7, it all depends how loud you want to play and how big your room is or distance from the speakers. The 3.7 is rated at 92 dB for 1 watt and pretty efficient. The stability of an amp at 2 ohm is relevant but the need to double power from 4 to 2 ohm is only meaningful if you use the maximum output. I based this on experimenting with the bryston 7bst, which allows to switch from parallel to serial, with a minimum impedance cut in half. No difference at any level below 90 dB listening level. 

Unsound and Tom. As you know the 3.5 individual drivers are all above the 5 ohm across the whole range and combined stay above 4 ohms. Makes it very suitable for tri amping or bi amping. I would guess that bi amping the bass and mid-tweeter with one amp would be better then using the amp in serial configuration for all drivers. Is that consistent with your experience? 

Tom, when you say that you listen at spl peak of 90 dB, is that at listening position and if so, how far from the speakers or is that near field?

My waveguides came off easily. Don't remember any difficulties separating them from the driver. To the best of my knowledge, Rob does not included the waveguide as he told me to reuse the guides. 

Unsound, I mostly agree with your preference for the 3.5 but can't say that it is better then the 3.7. 

Unsound, or the 3.5 with the coax from the 3.7 and a pair of sealed sub woofers.

Thoft, are you importing your luxman yourself? A while back I did some research and noticed a significant price savings if you can live with the voltage adjustment and warranty. Which model did you order? 

Bonedog, I would be curious about your measurements before and after you installed your new midrange. Did you use rew?

You could be lucky and arrive at a great sounding system by trial and error. But this is a situation where experience with measuring pays off. Learning to make valid measurements pays dividend in the long run.

Questions about the proper amp for Thiel speakers come often up here. I would answer such a question by inquiring what is your standard and weakest link in the chain. I have yet the standard for myself to have a resolving chain of 16 bits or better, which translates to a thd+noise of each component better then 96 dB. With a streaming source of music or a high quality cd player, the (pre) amp becomes the weak link. Here is a link to a database of amplifier measurements by 3rd parties.
https://docs.google.com/spreadsheets/d/1ZlTOYxmPs938gqHjtDABkWS-MApu7uJjzIGnJ2Elm6Y/edit?usp=sharing
Benchmark leads the list and hypex based amps are well represented near the top. For the diy, the plate amps of hypex are a great and affordable option to have a complete digital chain from beginning to end. 

Check audiosciencereview.com for their listing of reviewed dacs with pre-amps. 

Jon, get a purify amp, or an hypex amp if you want to safe some money. Almost as transparent as the benchmark, twice the power, half or less the money. 

But what about the facts? Although Thiel claims that the phase is within 15 degrees, I have not been able to see that in any of my measurements. Time coherence on the direct sound is fine and at 10 ft measures within milliseconds. But then there is the indirect sound which is of course determined by the room characteristics. The first order xo have less minimal phase changes, but they are still there. Not to mention that the drivers are have their phase changes and they don't cancel each other out. I have worked on digital active cross overs to approach linear phase +- octave around cross over frequencies and was able to improve the phase coherence but did not have the ability to conduct a blind study to determine differences or improvements. I think we can do nowadays better to really establish the facts of time coherence and listening preferences especially with klippel measurement equipment becoming available. But I don't see the willingness to really find out the facts and integrate it with the subjective experiences. 

Thoft, bring it to the attention of the owner of the house. Without ground, your fuses or circuit breakers may not be effective and cause a fire hazard. Don't live with that risk. It should get fixed. 

If we had a sticky option, I would elevate Tom's description of thiel speakers to that status. It is fully consistent with my experience.
The 3.7 with sub woofers is an excellent system.
Tri-amping with eq for system and room effects has done wonders for my 3.5, coming very close to the 3.7 system. I can only imagine that 4-amping with eq the 5i would easily match the 3.7 with sub woofers.
By the way, I think that going with multi channel amp and DAC plus eq is essential to mitigate room effects, affordable compared to high end amp and solves most technical short comings of high end thiel speakers. It's fun too. 
I have settled on a 8 channel hypex ncore252mp amp, a laptop with Adobe audition software and a motu interface to conduct my experiments. 

Unsound, before you dismiss the multiamp option for the cs5i, I would be surprised if the impedance of each woofer would be lower then 3 ohm. In parallel the impedance of 3 woofers of course drops to the low level but if each woofer is powered separately, the need for high current amps disappear. The specs on the hypex ncore 252mp are easily available and have been confirmed by independent measurements. These opinions about multi amp vs Krell could be empirically tested if the goal is to improve the sound quality of the cs5i.

Brettmcee. If you don't have a way to take measurements, send your speakers a mono signal and compare your left and right channel. Make sure they get the same source signal strength. Listen carefully if you can detect any differences between left and right channel. If there is a difference, determine the cause. 

Listened to the section on qobuz at modest volume and was not able to identify any distortion.