Nice to see all these Thiel pixels! My (memory of) 38" ear height relates to average seated ears. I don't know what height was assumed after mid 90s, but probably the same. Measurement distance is 3 meters with an assumption of that as minimum listener distance. Notice how little tilt would be required to adjust for spikes at 10' to 12' assumed distance. Rob, or anyone, please correct me if 38" is incorrect. One day soon I will have spectrum analysis equipment to verify such matters going forward.
Regarding measurement methods. Thiel did have a SERIOUS anechoic chamber at 20' high x 30' wide x 50' long (approx). Room reflections shelve at 200 hz. We began life balancing for 2db down below 200 hz and above 200 hz flat out to 20K+. That target was modified over the years to conform to general industry practice, AGAINST Jim's wish for FLAT is FACT, not opinion!
Jim had designed and built an interrupted pulse stepped signal generator which fed 1/3 octave pulses to the speaker (6' off the ground), @ 1 pulse acceleration, 1 pulse measured -calculated room decay before next pulse cycle 1/3 octave higher. Pulse sweep was 20Hz to 30kHz.
Jim also used rapid full-range sweep above 200Hz and noise burst / Fast Fourier Transforms, before such stuff was available on PCs. Oh, there weren't any PCs when Jim developed these tools.
All those measurements were correlated with free space measurements (speaker suspended from edge of roof 20' above ground) and half space (ground plane) with speaker firing into open space (woofer bounce) and firing down-angled with mic at position of first ground bounce, and buried in the sandbox for infinite baffle response to isolate edge diffraction effects. All these measurements converged into a well-rounded picture of frequency, time and power response where we knew how the speaker would interact with a room. Thiel believed that speakers should do their job of flat response including edge diffraction, and the room must be massaged to do its job of even support. I don't know where these presumptions landed by Jim's death in 2009. An earlier commentator above shed light on that; Jim may have migrated away from flat to align with generally held expectations. I always wanted to garner consistent assumptions from the recording engineering community, but we couldn't find consensus there. Everybody second-guesses everybody else!
Larry Staples was an early Thiel pioneering dealer in Louisville. He and others like him forged a new path in audio which became known as "high end". Hello Larry.
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One more thing. It's important to note the depth and breadth of research and development that Tom and Jim worked on and succeeded in, in designing loudspeakers. They approached each issue three dimensionally. As Tom so accurately states, every solve has a side effect which may introduce more problems than it helps.
An admission of mine. When I Founded LSA Group a decade or so ago, I voiced my speakers only to 'sound' the way I thought seemed natural. And because I have a good sense of music, they were enormously pleasing. There was NO science involved, NOTHING akin to the task undertaken by THIEL AUDIO. Jim will be forever missed.
Tom accurately states that the new THIEL owners, rather than 'Tilt at Windmills', simply tried to exist with a 'me too' product.
It is a shame that Jim did not have a like minded young engineer that he could have passed a wonderful legacy of work on to.
Best to all,
Larry
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How wonderful to see a dear friend Tom Thiel contributing to this site. I hope all is well for you and yours Tom. Write me some time on FB.
Larry Staples
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My pleasure ranchhand1
hope you are well and playing good tunes for me today. Happy Listening! |
Prof, What’s your distance from speaker to seated listening position?
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"The outriggers and spikes on my CS2.4SE raise the speakers a good 2""
That's one reason I haven't used mine. Even raising my speakers on shorter footers has changed the sound in a way I don't care for.
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Beetlemania, Thiel measured anechoicly, though I wouldn’t be surprised if that was limited to perhaps 200 Hz and above. I hazard a guess; it’s the latter. |
Much of the spike length was intended for carpet height piercing.
The outriggers and spikes on my CS2.4SE raise the speakers a good 2". I think these spikes are a bit longer compared to the standard version. About one-half of my floor is slab and tile with a hand-woven rug under the speakers. I use 1.5 x 2 x 0.25" wood blocks under the spikes to protect the rug. The other half, which includes my listening seat, has wall-to-wall on top of the slab. I find the spikes to improve the SQ at least a little altho' not sure how much is due to listening height v. better coupling to the floor. |
@beetlemania, I don't think it did too badly at low volumes but I cranked it up pretty quickly to see how it would do with something loud and meaty and it wasn't up to it. I was at the dealer and I didn't spend a whole lot of time listening for subtle differences. I find that it takes me a long time to make up my mind about whether something is different, better or worse and I can't really do it at the dealer. I listen to make sure it's about what I want and then take it home and usually need weeks to make up my mind 100%.
I'm also a believer in having too much power. It might be my imagination but I think having what would seem to be way more power than necessary makes a difference. My current setup has 2 200 watts@8ohm/channel amplifiers running bridged mono. I've had this setup for 10 years or so and I prefer it.
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From the manual for the CS2.4: Optimum phase and time alignment is provided only for a seated listener who is eight or more feet away from the speakers. There is no mention of ear height, which is very important for the first order filters (ie, vertical dispersion).
Measured at 3 meters.
That's >twice as far as Stereophile in JA's open air arrangement and 1 m more than Soundstage in their anechoic chamber. Do you know if Thiel had an anechoic chamber? Or did they measure outside? Must have elevated the speaker well off the ground if the latter. Comparing Stereophile and Thiel measurements (published in Audiophile Journal archived on the Vandersteen website) it's quite clear that Thiel measured from farther away. Not only do the Thiel measurements indicate much flatter frequency response, the waterfall plot is much cleaner than suggested by Stereophile, with a clean initial decay even in the upper midrange. |
The spikes add minimal consequence at the recommended seating distances. Much of the spike length was intended for carpet height piercing.
For some the energy drain into more vibrant floor boards will negate the spikes advantages.
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Thiel recommended a minimum of 8’, preferred 10’, extended to 12’. Measured at 3 meters.
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38" ear height is design target. I imagine there must also be a target distance to the listener, as well, that corresponds to the 38". In Soundstage’s measurements of the CS2.4, they measured at 2 m which is their standard. But the height was a manufacturer-specified 30" from the bottom of the speaker (presumably w/o spikes). |
Thanks jafant for finding and posting contact information for Rob Gillum's
Thiel speaker service company. My mint condition 1986 Thiel CS2's continue to please to no end. Come the day they need attention I know who to call...:) |
If I may:
that’s the ear hieght
(+/-?) of the typical seated listening position.
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@tomthiel
Thanks Tom.
Just to be clear, when you write: <i>"38" ear height is design target."</i>
Does that design target assume the speaker is on spikes or not?
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@jon_5912 Stereophile measured the CS3.7 impedance as low as 2.2 Ohm, so even the more powerful AX-5 might be a marginal match for big rooms or loud-preferring listeners. Still, I'm surprised the AX-7 didn't at least deliver good sound at moderate SPLs. Wes Phillips used several amps for his CS2.4 testing including a vintage Fisher measured at 6W into 4 Ohm!
. . . while not my first choice for the job, did not acquit itself too badly.
But for his review of the CS3.7 he used the Ayre MX-R and Musical Fidelity Nu Vista (480w into 4 Ohm). |
For long posts that take a while to write you should enter them in notepad first and then paste them into the web page when you're finished. That way if something goes wrong when you push post you won't lose it and can just do it again. |
Prof, my detailed response didn't show up. Hmmm. Bottom line is that the height change from feet is very small compared to the sonic integration triangles at normal listening distances. 38" ear height is design target. Baffle motion from recoil forces is substantial for short tweeter wavelengths. Spikes work.
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@beetlemania - I'm not 100% sure but I think it was the little one. |
Good to see you- oblgny
Rob sees the bigger picture. He is very easy to reach via phone or email and a class-act. Which model are you scouring?
Happy Listening!
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I sent Rob @ Thiel a very brief email congratulating him on continuing with the excellent service that he has already demonstrated over the years. Though my email did not warrant a reply, Rob did - and quickly. And I'm not even a customer at this point.
I'm scouring the ads now to "invest" in yet another pair of Thiel. I j just can't NOT support this guy!
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@tomthiel,
Regarding raising/spiking Thiel speakers.
I’ve generally had the best success in my room with my 3.7s/2.7s (and other speakers) sitting right on the floor, no spikes. (It’s a wood foor covered in a shag carpet).
However, I’ll probably try spikes or footers again at some point and it makes me wonder about raising the coax driver relative to my ear height. Right now I’m in a nice sweet spot but if I raised the speaker on spikes/footers I may change that. Therefore, I’m wondering about compensating for raising the speakers via altering the angle - that is raising the back of the speaker a bit more to tilt it towards me, to maintain a more precise relationship with the drivers.
As Thiel speakers have a precise slope angle for integrating the arrival time of the woofer with the coax, I’m wondering if altering that angle via tilting the speakers a bit forward would be deleterious or not. (Or even change the floor woofer’s intended relationship with floor bounce, or other parameters I’m not thinking of).
What are your thoughts?
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Right On! beetlemania
Happy Listening!
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Hopefully, Stereophile will include the Coherent Source Service article in the Industry Updates section of the print version. Maybe Rob needs to tell JVS that Thiels will fill your room with the sounds of MQA. That should move him to the top of the queue!
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Absolutely! beetlemania
Much Thanks for sharing your information on mods and hot-rods as well.
Jason Victor Serinus (JVS) really stays up to date on the industry side of Audio, informative too.
Happy Listening!
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Glad to see Stereophile spilling some ink, or pixels, for Rob Gillum!
I'm assuming the "hot-rod" kits are, thus far, limited to the leftovers from the unbuilt CS2.4SEs. Maybe we'll see other options in the future per Tom Thiel's posts upthread?
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I have exchanged a few e-mails with Rob Gillum re: CS2.4 mods. The short of it is he has kits to upgrade CS2.4 crossover to CS2.4SE equivalent but not an upgrade path for CS2.4SE. He did supply me with a schematic, so I will strike out on my own into the wilderness ;^) I will post more details on this thread: https://forum.audiogon.com/discussions/thiel-cs2-4-upgrade-to-cs-2-4-se?highlight=thiel%2Bcs2.4Moreover, he also has the outriggers, including stainless steel spikes, of the SE version. Other than the birdseye maple with vermillion stain, you can upgrade your standard version to a CS2.4SE. Now, I kinda wished I had waited a few weeks - I coulda saved some money. Rob was very helpful - please, everyone, support him as you can. |
If all was there so would the power. |
Alright guys Anthem reported that the integrated does provide 30 A of current at 2 ohms. I am hoping to receive a bit more information on its application- continuous, reserve or peak?
Happy Listening!
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^Jafant, wasn't that with different speakers? |
Never any need to apologize- beetlemania
I tend to concur w/ the quote as above " more power produces an effortless transient attack that really makes music work emotionally."
I am (certainly) in touch with that emotion per the audition last week.
Happy Listening!
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In my opinion amplification and all other elements of the chain are very germane. Thiel speakers reveal upstream misbehavior extremely "well". This battle never ends because only by ultra-resolution can we retrieve the inner detail of music.
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The current behavior of your Ayre is of interest. But, more power
produces an effortless transient attack that really makes music work
emotionally.
To the best of my knowledge, Ayre, Theta and, maybe Dartzeel are the only manufacturers of SS zero-feedback amps. The Ayre VX-5 stereo amp has a bit more power than my AX-5 integrated (rated at 300 W into 4 Ohm). Stereophile measured the MX-R (non Twenty version) at 595 W into 4 Ohms and 720 W into 2 Ohms - but that product is WAY beyond my budget. The Theta Citadel ($12K) is rated at 400 W into 8 Ohm and 800 into 2 Ohms. The Dartzeels are generally more expensive than Ayre or Theta and also less powerful other than the $150K behemoth reviewed by Fremer (1025 W into 2 Ohms!). I wonder how *that* would sound driving a modded pair of CS3.7s! I think there are a handful of tubed zero feedback designs but these are probably less powerful than the above. And with that I apologize for taking the "Thiel owners thread" off topic! |
According to the article cited by beetlemania -
JA measured 220w clipping into (2) Ohms w/ one channel driven.
tomthiel -
Thoughts?
Happy Listening!
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An amp with zero loop feedback must be extraordinarily well designed to work for music. Feedback disturbs phase response. Ayre is addressing design from first principles and I would expect all their products to be very clean, especially in the transient-temporal domain. If it sounds clean it is clean. But, the joys of power should not be underestimated.
I hot-rodded my 1990 Classé DR-9, considered a high voltage / high current amp. In stereo it produces100 wpc > 8 ohms, 200 > 4 and 400 > 2 ohms. Nice muscle and finesse. Strapped to mono it gives 400 wpc > 8 ohms, 800 > 4 and 1100 > 2, which means the power supply runs out of current before voltage. I use them in my studio where they are surprisingly cleaner strapped than in stereo at moderate levels into a moderate sized hard-to-measure space described earlier. Anyhow, I would have thought that the 400 > 2 ohms in stereo would have been plenty, freeing the other amp for other duties. But the improvement was dramatic enough to assign both amps to mono duties.
The current behavior of your Ayre is of interest. But, more power produces an effortless transient attack that really makes music work emotionally.
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Thanks! much- beetlemania
maybe I can find an AX-5 near my locale for an audition?
Happy Listening!
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@jafant The Ayre has plenty of balls for my room (18 x 19 x 8-12) and listening tastes. The "VGT" volume control has 46 1.5 dB steps and I usually listen at a 20-24 when I have the house to myself, maybe 26-28 if I want some rowdy rock. The highest I've pushed with the Thiels is 30-32. No apparent distortion but this level becomes uncomfortably loud. With the Vandys, I had to add about 4 steps to attain similar SPLs (as an aside, I could get my old AX-7 to clip with the Vandys but, again, that was at SPLs too loud for me). Ayre does not give the AX-5 a 2 Ohm rating. Here's what JA said in his measurements:
That the AX-5 was not as comfortable driving 2
ohms as it was higher impedances can be seen in fig.6. This plots the
THD+N percentage against frequency at a level, 8.9V, equivalent to 10W
into 8 ohms, where I could be sure I was looking at actual distortion
rather than noise. Into 8 ohms (blue and red traces) and 4 ohms (cyan
and magenta), the THD+N is very low and hardly changes with frequency,
which again is a tribute to the zero-loop-feedback topology. But into 2
ohms (green), not only is the THD higher, but the level was a little
unstable at the lower frequencies.
Apparently, power is slightly higher with the Twenty version but I have no idea how that might change JA's THD+N measurements. Again, I would be reluctant to drive CS5s (impedance drops to 2 Ohms in the bass) with an AX-5 but I hear no deficiency with the CS2.4SE. |
beetlemania
are you playing the Ayre as loud as you wish? Does the AX-5 measure into 2 ohms?
Happy Listening!
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Excellent points/counterpoints -beetlemania
I concur about the upstream components being easier to detect by listeners. Happy Listening!
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I concur with you- marqmike
Happy Listening!
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I did not view the post as venting- tomthiel
I found the information more informative with additional insight into the speakers. I received a reply to my query from Anthem reporting that an attempt will be made to ask the engineers for current in (A) measurements.
Happy Listening!
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I find my 2.4’s very easy to tune in to my room and equipment. Maybe because their design causes them to be close to a truly neutral piece that you can go many ways and get great sound. I had some 1.2’s. They both are/were easy to make warm and round, or razor edge outlines and very transparent, or anything in between. One thing among other things I like about the Thiel’s I have had and others that I have listened to for some time is they communicate well. I don’t know how to describe it well, but I consider music to be communication of a sort from the musician, the instrumentalist mainly but also the vocalist, and that is what I want from my music, and I get that more over a wider range of music from these speakers than I have from others I have enjoyed listening to over the years.
Anyway like Tom thanks for letting me vent. Just kidding. Hope everyone is enjoying their systems. And thanks to Tom we are enjoying our systems a little more with some insights behind the speakers. |
Thanks for the rant!
There are further involvements and interactions resulting from coherence
that relate to the amplifier discussion above and many more aspects of
sonic performance. In business it is impolite to blame the upstream
signal chain for less than satisfying sonic results. But truth be told, a
coherent speaker doing its (Thiel defined) job of absolutely
representing in all domains the input signal fed to it has an impossible
job. There are thousands of ways that a signal is corrupted from
acoustic (or augmented) event, through the recording, storage and
playback chain to reach the listener's ears.
In this thread and elsewhere, some have opined that Thiels are less forgiving of amps and this lines up well with your comments here. Most Thiels do an excellent job of reproducing the signal fed to them. That is, they are highly resolved, transparent and neutral. But it's a precarious position. Flaws in upstream components (amps, sources, cables, recordings) are more readily heard by listeners. Listeners (and reviewers) with flawed gear might mistakenly blame the speaker as the Thiels reveal the flawed gear. But the flip side is the possibility - with exemplary amps, sources, and cabling - of standout performance; great musical clarity and emotional connection to the performance. And this is what I'm hearing in system :) |
Stereophile's measurement design is an example of what I believe to be a fundamental lack of understanding of the ear-brain and its response to whole-goods: that is sound with its tonal, spatial, transient and dynamic characteristics, to name a few, intact, unadulterated, coherent. Aural intelligence is a profound function of human existence and more closely related to the other senses and, in my opinion, the development of consciousness than is generally appreciated.
Over the years the critics were very supportive of Thiel's designs and products. I believe Thiel products garnered more international design and engineering awards than anyone else in the world. We couldn't have asked for more support. However, most critics didn't really get it. If they had, they would have designed measurements (applicable and informative for ALL audio products) which illustrated performance in all relevant domains. Instead, the tests support the prevailing wisdom which I believe to be partial and flawed.
In this forum and elsewhere I have heard people wondering why Jim didn't prune an heir to carry on his work. The answer is complex but it includes the vicious cycle I site. Engineering candidates dismiss the reality of factors that fail or fall outside the measured paradigm. To summarize a very deep matter, all candidates state with full conviction that phase coherence cannot be implemented along with frequency domain success. (that's a period.) And if they could be co-implemented, then it still wouldn't matter because the brain doesn't care about it; ask anybody from the Canadian Research Council or any other proper institution of research or learning. And since it (fully coherent reproduced sound) can't be accomplished and wouldn't matter anyhow, then why would I (the candidate) risk my career and standing in the professional community to swim upstream against prevailing wisdom. Short story: Thiel Audio DID search long and hard for many years without success. The Tennessee Buyers committed to carrying on the work; and no small part of their reversal was based on their research which supported the conclusion I stated: forget it, get with the times, hire Mark Mason and get on with the prevailing paradigm.
I suppose I'm ranting. I do really appreciate you guys for getting it. Very few people do. There are further involvements and interactions resulting from coherence that relate to the amplifier discussion above and many more aspects of sonic performance. In business it is impolite to blame the upstream signal chain for less than satisfying sonic results. But truth be told, a coherent speaker doing its (Thiel defined) job of absolutely representing in all domains the input signal fed to it has an impossible job. There are thousands of ways that a signal is corrupted from acoustic (or augmented) event, through the recording, storage and playback chain to reach the listener's ears. Almost all practitioners along the way default toward euphonic engineering, trading off against the non-important aspects, which muddles the mess nearly beyond redemption. I think that any, perhaps all, of you Thiel aficionados would love to have witnessed the thousands of hours spent ferreting out the contributing factors involved in creating an honest transducer. When the speaker is coherent then EVERYTHING matters. That's how we identified wire, magnet eddys, diaphragm propagation moires, diffraction and so forth and so on from the O3 development and onward year after year making progress toward an impossible goal of authenticity and integrity, knowing we (the speaker) would be blamed for exposing problems not of its making. Since the history is ancient, you may not be aware that Thiel put those elements (wire, etc.) on the table before they were acknowledged in the audiophile community. Many elements are still contested all these years later in the pro and academic communities.
Back to Stereophile's tests. The 50" (etc.) standard could be circumvented for very little investment. Outdoor measurements are anechoic. Tilting the speaker to a ground-plane microphone eliminates floor bounce, And so on. The problem isn't about accomplishing the test, it's about ignoring the importance of all of the outcomes. Aiding and abetting falsehood is an entirely invisible and unintended consequence.
I should get back to work. I hate end of year bookkeeping. Thank you for the opportunity to vent.
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popularly-held fallacy that phase and time information don't matter or
can be misrepresented in test design is that such measurement techniques
are given undue validity by most
Hi Tom, are you referring specifically to Stereophile's step response measurement or something broader? |
