Thiel Owners

My understanding is a faster slew rate for a given component is better -- up to a point at which little-to-no difference is heard.  Musical transients are only so fast, and if the component is substantially faster than the fastest musical transients, generally straightforward to do these days, you're good.  That's not to say within the component you don't need much faster slew rates, like the I/V converter after the DAC chip.  Sort of like high-frequency response and harmonic distortion.  Above say 300kHz and below say 0.01%, do better numbers equal better sound?  My indirect experience says after achieving these specs, focus on other elements of the circuit or internal components to optimize the sound by ear and less-conventional numerics.

Also, for many of these specifications, there isn’t any internationally agreed-upon measurement technique or standardization for something like peak current. An amp may deliver 60A peak for a millisecond, but any musical transient is much longer than that. But for 250 ms, that same amp may only be able to provide say 20A, and perhaps 8A continuous.
The last time I believe this was standardized was the IHF dynamic headroom measurement, which was how much more power was available on a 20ms toneburst than on a continuous basis. But even this method was compromised as it was found that most fast musical transients are in the 80-200ms range, and I don’t believe a 200ms dynamic headroom test was ever standardized. Others may correct me.
Back when this was part of an amp’s specs, a doubling (spec'd as 3dB) of the continuous power output with a 20ms toneburst was considered respectable.

tomthiel -- and I presume his determination applied to the amplifier's ability to triple its short-term output into the lowest frequencies, the most problematic for any amp.  I believe the IHF dynamic headroom test specified 1kHz, which obviously had little-to-no bearing on the amp's headroom into the bottom octaves. 
Manufacturers were then spec'ing continuous power output over the full 20-20k Hz bandwidth, but many of those amps were tapped out at 20Hz.  Ask them for more power at those frequencies and it's no surprise they'd clip and burn tweeters,
How many amps of that era actually had the balls to triple their continuous output for 1/4 second at 20Hz into a demanding Thiel load??  That sounds like quite a feat for even today's best amps!

The antithesis of the 'classic' Thiel sound, often stereotyped, never copied? I'm pulling these purely out of memory from dozens of audio shows and general familiarity, not A/B home listening!  I could be wrong on any of these, corrections are welcome.

Sonus Faber, rich, romantic, not particularly 'fast.'

Harbeth, Spendor, or several British speakers (among others I'm sure) that still have the 'BBC dip' as part of their sonic design intent (a dip in the upper midrange to make them sound less-forward, more-'polite').

Magnepan or Apogees, the opposite of box speakers, with dipole radiation, narrow lateral dispersion, broad wide imaging (the antithesis of 'pinpoint'), limited bass dynamics and extension, certainly not bright. (I'm leaving out true electrostatics as so often reviewers compare Thiel's speed and coherence to them).

Horn loaded speakers starting with Klipsch, including some of the Cerwin Vegas mentioned. Huge SPLs with no danger of frying a midrange coax.

Not that any of these brands are innately 'inferior' or 'worse' than Thiels, but that their design briefs -- by choice or speaker type -- are quite different.

Just ignore my pontifications about the differences between 2.3 and 2.4 on those 2005 threads, as they were made based on several hours in an audio showroom.  I've had both in my home now for 15 years and my opinions have 'matured.'

mobilesax -- I've heard Merlin VSMs at a few audio shows and at one store, but not in my own room vs whatever speakers I've owned at the time.  I've had the utmost respect for his creating a solid design and then constantly refining it year after year to as fine as it could possibly be.  That a pair of vintage Thiels of unknown condition one step away from the dumpster could so impress you says a lot about both the Merlins and Thiels, and certainly your electronics are 'adequate'!  

More to the point, if you do score a pair of 2.4s, a thorough listening contrast would be appreciated, if only by me, because those two speakers were on my short list a 15 years ago.  I didn't get the Merlins, so I'm still not entirely sure what I'm missing, though I can't complain about my 2.4s.

I have to say I laughed out loud when I read Bose used Thiel as their audio benchmark.  Would anyone venture a guess as to how well 2000s-era Bose speakers emulated the 'Thiel sound'??
I'd be curious to know what they use today for their large(r) speaker benchmark.  I'm sure someone would have to know a Bose insider to find that out...

jafant, a 'nice' thread, but not a totally accurate one wrt my assessments.  I'm sure I updated my impressions more than once since I've had both speakers in the same room in 2006 and since.  I'll be putting my late-production 2.3s up for sale soon.

I was always on A’gon years ago, but brought back now with the final death of Thiel, Rob Gillum’s phoenix rising, and XO questions.

I replaced the caps in my CS2.4 in 2011 and can clearly answer the questions asked so far. Only way in is by removing the passive radiator with their unusually-sized allen driver. Two separate circuit boards, for the low-frequencies on the base and the HFs on the back (above the binding posts). Unless you don’t solder, little to be concerned with because everything is so BIG and the circuit boards (in at least my earlier units) are made of wood. Best access is with speakers on their back. But even then, expect some contortions to all your work through a 7x10" opening.

Thiel sent me a schematic of the crossover, and I believed Thiel's hours of assessments that the ClarityCaps SA gave the best sound. But I one-upped the 2.4SE with the next-higher model, the ClarityCap ESA. I replaced only these caps as they’re the only ones in-line with the coax actually passing signal, the others are paralleled for impedance matching and frequency contouring.

I researched the caps as needed here, and there are probably newer better caps since 2011, though for a price.
http://www.humblehomemadehifi.com/Cap.html

and I bought them from PartsConneXion (a 27uF direct replacement and a 10uF || 3uF = 13uF). PCX will also match each pair of caps, a big plus for speaker consistency and imaging even with +-3% rated caps.
 I also bypassed them with the then-recommended Vishay MKP1837.

Take a picture of the stock crossover before you start pulling it apart.

I cut the Axons out but kept 1" of their leads to attach the new caps to, and then had to smoosh the larger caps in their place, snuggling them up around surrounding components. I used ShoeGoo to hold them in place to the base and/or adjacent caps to buffer them from vibrations. Once everything is laid out to your satisfaction only then fire up the soldering iron and complete the job. Just be VERY careful how you place your soldering iron as it’s very near a giant woofer magnet and a hot soldering iron being pulled through your woofer cone could make for a very bad day. After you’ve done one speaker, take a break for awhile. When you’re fresh, you’ll do the second speaker in half the time.

It’ll take a long time for these caps to break in to the point where they sound better than what you took out, so put the FM white noise or CD player on repeat 24/7. Having become so familiar with my 2.4s stock, I can confidently say these new caps give a greater purity to the coax, greater air, delicacy and inner detail. Also, better imaging due to tighter cap tolerances around the crossover frequency. Not hugely night and day, but making a good speaker that much better for very little money and time.

I’d post pictures if I could...

While I'm posting for the first time in years, I can vouch for Rob Gillum's excellent solo work.  I had a CS2.4 coax go silent on me a couple years ago, long after Thiel-proper was gone.  To assure consistency, Rob had me send him both my coax drivers, which he rebuilt from the ground up using the latest adhesives and various tweaks developed since their 2004 inception, and their later (relatively) mass-produced manufacture. 

The sound of my 'old' coaxes was so firmly embedded in my ears that once the rebuilt ones broke in, there was no question I was hearing a purer, faster, more delicate sound, with better left-right matching too.  Again, not night and day, but another notable step up to this long-term 2.4 listener.  And the hope that these drivers will last 'forever.'

asiaaudiosoc

I have both 2.3 and 2.4 for some time now. I’ve had my 2.3 coaxes replaced once (while real Thiel was still in business and they had production coaxes stocked), and 2.4 coaxes replaced several times. The most-recent replacements were soon after Rob was up and running. The sound improvement was substantial. Rob explained this as his rebuilding them by hand as a matched pair with more attention to detail than what they could achieve in a semi-mass production flow; the big improvements in adhesives since then; and some of his ’secret sauce’ in minor build improvements to the driver that improve its performance without altering its specifications. (surrounds? mid/tweet decoupler? tweeter dome? spider design? voice coil wire?)

So yes, I can confirm your observations. Now I want to see if the same magic can be applied to the sonically ’challenged’ 2.3 drivers!

I can offer what I find to be nearly ideal for my 2.4 listening position/setup.  Speakers 8' apart center-to-center, toed-in 10 degrees each or less, grilles on.  9.5' coax to my ear.  38" listening height.  I use the coax as my reference point as that defines the source of the most-directional sound and imaging and phase information comes from when making small adjustments to position.

But I've used the spikes to tilt the speakers back an unspecified amount, a little bit because my ear is 2" higher than design, but mostly due to having more vertical latitude for frequency balance.  Stereophile's vertical response graphs illustrate (though perhaps at too close a distance) that response above the coax axis sucks-out the lower-mids, and below the coax further fills-in the lower-mids.  So even if I give up some degree of time/phase coherency by tilting the speaker further back (altering arrival times ever-so-slightly from spec) I get more wiggle-room before midrange suck-out.

Additionally, each speaker is pretty much in free-space,  6' from cabinet edges to either side wall and 3' to a 'soft' back wall, 6' to a 'hard' back wall.  Nothing at all diffractory around the speakers or between the speakers and my ears, or even to the sides, after a little living room tweakage for a proper listening session, ie move the coffee table behind the speakers rather than right in front of the couch. 

A thick pile carpet, soft cushy furniture against the back wall, and an 8'x2' acoustical absorber behind the couch/listening positions.

RTA shows a lumpy low-frequency response due to my open floor plan asymmetrical living room (though this also puts 25Hz at 0dB ref 1kHz!), but otherwise lets the Thiels be Thiels with as little room interference as possible.  So I'm fortunate my current living space allows for such a great setup for any speaker to sound their best.

dhoff01: raising the speakers 2" on the spikes, if they could go up that high, would be precarious and less-stable.  Not that sound travels this way, but putting a laser pointer atop the speaker and raising the front spikes 1" up moves the laser pointer up 8" at my 9' listening distance.  I'm doing this to manage a taller vertical listening window w/o suckout, even though I'm sure it takes a very small hit in overall coherency.  The tiny amount of potential phase shift from this is still far better than every non-time-aligned speaker out there!

Regarding the positioning, a lot of it is a function of living room WAF symmetry.  But the walls to the side and rear are so far away from the speaker boundaries, I can't believe they play a role at these distances, especially because none of them are 'true' walls in my open floor plan.

If my toe-in was any less, it wouldn't be visible.  It was from putzing with speaker width apart vs soundstage breadth vs HF balance.  If I went from <10 deg toe-in to zero, the effect would be minimal for sure.  But after 15 years of tweaking these speakers to this acoustic, I can now notice ridiculously small changes.  So rather than obsess about it, I take the time to find a reasonable compromise and let them sit in that position for years :-)

The butcher blocks aren't a solution for me due to WAF and stability, and with Tom's information, why upset my frequency balance, when the bass in my room is outstanding as is?  But is tilting the speakers <1" back on spikes, which tilts the baffle back the same amount, launching the wavefront 'higher', as the laser pointer indicates 8" higher at 9'?  Even if in so doing I lose a couple degrees of phase and gain a taller listening window before midrange suckout?  Or don't I really?

   I now realize what I've been misinterpreting for fifteen years.  The infamous Stereophile measurements are taken at 50".  Their 2.4 test figure #5 "vertical response family" shows the 1kHz crossover suckout just above the tweeter axis. 
   So at my 9' listening position vs their 4' measurement position you suggest I have far more leeway for vertical response, even though my 38" listening position is only 2" above "ideal."  Whew.
   I can't understand how JA's 50" measurements correlate to the real world for any speakers but pure-nearfield mini-monitors, regardless of XO design or driver spacing, especially the large multi-ways they typically test.

While you're on the subject of grilles, I'll hop in this forum for the first time. I've been lurking on it for a month or two but haven't read all 143 pages! I've been on Audiogon forever, but haven't done many transactions or forums here in the past decade. I have owned 2.3s since 2002 and 2.4s since 2006, probably one of the first owners to install the SE capacitor upgrade, though going to a higher-spec Clarity Cap.

What has always 'baffled' me is the 2.4 seemingly putting form over function by recessing the baffle with sharp edges all around for the magnetic grille cutout, and the grille itself having metal discontinuities around the perimeter of the coax. The 2.3 coax is mounted in a modest waveguide and the entire baffle back to the sides of the cabinet is a smooth rounded surface with zero discontinuities. The grille is a sock stretched tight over this that has no effect on diffraction.

With the 2.3 and 2.4 side-by-side, with the right source material, the 2.3 always throws a more-effortless and dimensional soundstage. After years of listening in the same acoustic and much the same equipment, and with listening material that has enough soundstage information, this has always been consistently repeatable. I can only believe the visibly far-less diffraction off the 2.3 baffle is why.

(With either speaker pair, I always listen with the grilles on and perhaps 5 degrees of toe-in in an optimal acoustic for these speakers)

I use my 2.4s 95% of the time because they're better than the 2.3 in every other respect, and their soundstaging is still 'sufficient.' Poor Gary Dayton had to field this question from me at least once after I got my new 2.4s side-by-side with my existing 2.3s. But the evidence here is still clear and the question remains, how did the 2.4's multiple baffle edges and discontinuities not offend Jim Thiel's fundamental design goals? And make it past all the factory listening tests to confirm the 2.4 was to be an improvement on every aspect of the 2.3?

solobone, I’d really like to put the 2.7 next to my 2.4. I’ve heard 2.4 side-by-side with 3.7, and obviously way too much of 2.3 vs 2.4...


cascadesphil, mine are late-production 2.3s, but my understanding of the changes to the coax wouldn’t affect the soundstaging I’m noticing as a baffle change between 2.3 and 2.4.


Andy2, I’m assuming you mistyped, because a high-pass filter will attenuate the *low* frequencies more than the highs!

I’ve seen a number of frequency plots over the years of grilles on vs off for a variety of speakers, and my memory is they nearly always show some degree of attenuation, ideally just the top octave, but sometimes they have funky and likely unintentional irregularities at much lower frequencies. As the grille rolloff seems < a 1st-order XO I don’t see why some modest XO tweaks couldn’t flatten out the response by a dB or less in the tweeter’s passband. If you know your XO topology to begin with.

But the more ’open’ sound without grilles IMO is as much the lack of an acoustic obstruction between you and the tweeter as it is a slight (relative) exaggeration of the highs.

   As soon as the 2.4SE came out advertising its improved crossover.  Thiel supplied me with the XO schematic and that their auditioning chose the Clarity Cap SA.  I went to PartsConnexion and went up one step to the ESA model, matched pairs, with paralleled bypass caps.  Had to use a 10+3 uF paralleled from their stock rather than a custom-made 13uF cap Thiel custom-sourced.  No other changes to XO (yet?).  

   It was a quick one-man DIY.  Decades as a working EE made this straightforward, if tight quarters.

   Despite the break-in time, it was clear the tightly-matched cap tolerances improved the image focus, and a smidge more transparency throughout the upper frequencies.  At this level of hifi, this was great bang for the $135 buck. 

   I'll add that having both coaxes rebuilt from the ground up at the same time by Rob Gillum post-Thiel collapse was similar to the upgraded, matched-pair Clarity caps, and also improved image focus and transparency a smidge.  But probably moreso because I have so many zillion hours listening to these speakers in the same good acoustic with mostly the same components and cables...

  Do you "share my sentiments" because you've *heard* with your own ears that the 2.4 doesn't soundstage quite as well as the 2.3?

@beetlemania

I do remember PMing a couple AG members about my specifics after I posted about my experiences. Were you one?

All your thoughts are well-taken. I perhaps wasn't clear on a couple points you expounded on. Thiel's 1uF bright yellow film bypass caps I didn't touch. I chose the 250V ESA caps for size to fit in the existing XO space for the prior caps.

At the time, at least with the suppliers I looked at, the ESA wasn't available in a 13uF, so I piggybacked a 3uF with a 10uF. The 27uF was stocked. So I never considered assembling what I could to do away with the existing 1uF film bypasses and go to 14 and 28 -- which would likely have required using different 1uF bypasses as ESA wasn't available in 4 or 28uF. I honestly haven't investigated other caps that might work in the XO since then, and I'm sure what you used are a result of deeper research and wider availability of good XO caps since my 2011 upgrade.

What I referred to as ' bypasses' are 10nF, the Vishay-Roderstein MKP-1837 that Humboldt Homemade Hifi (??) recommended for every XO cap application.

My audio friends at the time recommended changing out the XO resistors too, and I promised I would do on my second round, which hasn't yet happened :-(

Can I attach a picture to my posts, or only via a weblink to a photo-sharing cloud service?

   It turns out I *did* post to this forum about my 2011 XO upgrades on 2/2/18 (pg 49), with beetlemania and others acknowledging my relatively early surgery. 
   My 2.4s are fairly early production (SN 611,612) so I can confirm the high(er) quality original XO parts (including the inductors), point-to-point boards (literally), and wiring. 
   Due to nobody posting about 2.4 XO specifics in 2011, I had to wing it with only the schematic and XOs in front of me and Thiel telling me their use of Clarity Cap SA.  So I wasn't about to second-guess their use of film 1uF bypasses.  I had evidence the ESA I ended up using was a better-sounding cap than the SA, the CSA wasn't available yet, and the 630V caps and far-more-expensive Mundorfs et al were simply too big for the space on the XO board, so I used 250V versions.
   I don't doubt the XO can be improved well beyond what I've done, but as Tom Thiel points out, there are risks and pitfalls to just throwing the best and fewest parts at such a carefully-modeled 2-way XO.  I look forward to reading what Rob Gillum and team can accomplish with more resources than were available to me at the time!

   And I'm still waiting for informed comments about the compromises of the 2.4 baffle versus the smoothly rounded 2.3.  The 2.7 did away with the baffle discontinuities and should sound that much better due to both the baffle and certainly the 3.7 coax.

@tomthiel     
Sure wish I could post images directly.  Doing a google image search on the speakers in question will produce a few with the correct angle to view the issue at hand, below.

The 1.6 (and 1.7) are similar to the 2.4 about my concern of the recessed baffle.  The 1.5 is a very different mounting strategy from the 2.3.  The 2.7 baffle is again different from both the 2.3 and 2.4.

I will play with your felt solution with my 2.4, but in their case, this will disallow use of the grilles w/o some klugy modifications: most of the grille weight is supported by a pin above the coax, requiring the grilles remain flush against the baffle; the magnets help support the grille perimeter.  In my home, the grilles must remain on.

Here are quick and dirty links to reasonably good views of the 2.3 and 2.4 baffles:

https://www.alibaba.com/product-detail/Thiel-CS-2-3-Hi-End_11195163.html

http://www.hifi4sale.net/t38695-thiel-cs-2-4-used

@andy2
That's exactly my concern, problematic diffraction effects for the sake of "aesthetic appeal" fly in the face of all I came to know of Jim Thiel's design ethic.  And yes, he was alive and kicking throughout the CS2.4 project.
@beetlemania  
If your analog front-end is up to par with what I read earlier of your amplification, it would seem vinyl would be at least the equally-good source for critical listening!

I guess I'll be paying a visit to a tailor for the first time in decades (!) to try some of these materials.  Perhaps I could just put the felt around the coax's metal perimeter, up to the surround, as there isn't enough space to mill out the grille metal to the left and right of the coax baffle area.  That would seem to defeat the idea though, as I'd be attenuating all the coax output that isn't straight-ahead, vs allowing it to freely disperse unobstructed.  Which takes me back to the compromised 2.4 baffle in its entirety of construction :-|

I've never been certain how the 2.4 steel frame grille plate affects the diffraction 'problem' as it tightly surrounds the coax with 3 cuts at about 20 degrees, 0 (vertical), and 30 deg.  But the steel still presents as an edge, a discontinuity, for the coax wavefront.  It is just closer to the coax than the baffle edge when the grilles are off.  If you removed the grille cloth off the steel frame, it would more-clearly visibly *appear* to be problematic wrt 90 degree discontinuities closely around the coax.

I'm happy to entertain the soundstaging differences are from something unrelated to the baffle differences, which appear to be such an obvious contributor.  I've had my 2.3 coaxes in my 2.4s for extended periods waiting for replacement 2.4 coaxes, but beyond an interesting change of frequency balance, couldn't discern any soundstaging differences...

   "Acoustic Suspension" is a distinct variation on "Sealed" and I’m still not certain why that went so entirely out of favor for ported designs nearly universally decades ago. Make the cabinet a little bigger, power through a couple dB less efficiency, use a bigger woofer (or two), and get cleaner bass that rolls off at 12dB/octave instead of a ported 24dB/octave for far greater real-world extension without any phase shifting.
   With modern cabinet and cone materials and motors, I can't imagine a larger-diameter AS woofer with less excursion wouldn't play as loud with less distortion than a smaller ported woofer trying to move that much air though excessive excursions.     
   I had two of the best examples of AS prior to Thiels, but there were so many apples vs oranges the lower and percussive bass response was merely ’different.’

  I guess this is the time to ask, or confirm, that the incredibly comprehensive hyperlinked database of all speakers that was a part of the 'real' Thiel's website was immediately destroyed by the new owners?

  As I recall, it had every speaker's production dates, white paper, instruction manual, print marketing material, technical specifications, and all the positive reviews they could find from US and foreign sources.  

  If anyone mirrored or archived it, I have yet to find it...

In response to Andy 2 "Monday Quarterbacking" I'll offer that over the 40 year Thiel sales history, perhaps 10% of their buyers knew what a first-order crossover was, its real benefits and challenges. And perhaps 1% of those buyers knew the engineering well enough to truly appreciate the technical aspects, as Tom touches on above. That's just a total guess knowing the hifi buying population I've engaged with over 45 years (not as a salesman).

I'm perhaps in the 1% above (NOT "the 1%"!) and it still came down to lots of listening in audio showrooms in the brick and mortar days to Thiels versus similarly priced and respected speakers. I had a preference for their engineering, but if they didn't appease my sound priorities vs all the other good speakers of the day anywhere near their price or form factor, I wouldn't have bought 2.3s, and later 2.4s. I had no trouble finding Thiels among many dealers throughout the northeast with which to compare to many other brands. They didn't seem a 'boutique' speaker to me at the time, splitting the difference between say B&W and oh I dunno, Silverline Audio.

Also, Thiels were generally getting good to great reviews over the years, with 'too bright' being the most common complaint I recall. Thiel's "real" designs of their final decade seemed the best-received.  So I don't agree that things would have been any different if Jim chose to use higher-order crossovers to 'save' the company, assuming the voicing, pricing, cabinetry, etc were otherwise similar. Doing so would dumb-down the brand for the 10% and have little perceivable difference in the showroom for the 90%.  Perhaps the bigger 'problem' was Jim's solo brilliance and unwillingness/difficulty in finding a suitable protege, ending up with perhaps the dumbest audio-related buyout I've ever been aware of :-(

Thielrules, It seems your takeaway is IF you spend all the money on tri-amping, finding which drivers to replace or update with limited available resources, and (to some of us, compromising your signal chain by) using DSP that's not commonly done in most higher-end audio systems, only then will a 3.5 "approach" the sonics and performance of a baseline 3.7.  Even if his 3.6 is X% more-evolved than the 3.5, it would seem the 3.7 would be an easy replacement recommendation with an appropriate room acoustic?

Yabe1951, I have been powering my 2.4s with a custom SMC upgrade to my McCormack DNA-0.5 for a decade now.  We designed the upgrades for synergy with Thiels, including a scad of current drive into low impedances.  The pairing is perfect.  A recent amp shootout confirmed how well this amp sounds compared to the best-regarded amps of today in the $5k-15k range.  I can confidently say your amp will never need replacement for purposes of better sound!

jafant, it was sold as a nominally 100wpc stereo power amp.  Steve McCormack's estimates of mine is 125/250/500 wpc 20-20k@<1% THD into 8/4/2 ohms, absolute stability into 1 ohm, and as much as 60A peak current delivery depending on the measurement technique. 

Most of this power improvement comes from barely fitting in the custom Plitron power transformer designed for the DNA1 upgrade. 

Overall negative feedback has been reduced to 3-4dB (which is nearly zero by today's standards) and it will pass DC (at a much reduced level, and hopefully not) to the outputs all the way up to a 250kHz -3dB point, intentionally rolled-off to prevent ultrasonic issues...

Can anyone direct me to the pages that would have specific 2.4 vs 2.7 listening comparisons?  My understanding is the entire 2.7 low-frequency system is pure 2.4 (cabinet loading, woofer itself, radiator, XO tweaks only to better match woofer roll-off to 3.7 coax), yes?  The 2.7 is the only full-size Thiel of their last 15+ years I haven't heard.

@tomthiel, sorry I was off the forum for a week and didn't see your response about 2.7 development until recently.

I'm unclear why the 2.7 needed a HIGHER frequency woofer XO point than the 2.4's 1000Hz. The 3.7's 4.5" midrange should be able to much better handle lower frequencies than the 2.4's 2.5" midrange. Indeed, the 3.7 XO is at 300Hz, so the mid can go at least that low. So why not lower the XO point of the 2.7 woofer to say 500Hz for better power handling and even less beaming? That would stress the 2.7/3.7 midrange less than in the 3.7, and stress the 2.7/2.4 woofer less than in the 2.4, so a win/win with a lower XO point, but you state it is higher, and with 14X more capacitance, it would seem a LOT higher. Hmmm.  Please expound.

To that point, why wouldn't the 2.7 use 4x100uF film caps or even smaller to get to 416uF, rather than one massive 400uF? It would seem the slight increases in space and price 4 or more film caps would create would more than offset the potential sonic deficit of one giant electrolytic directly between the amp and wonderfully pure coax driver.

Indeed, that's the weakest link of the 2.4 for me, the excursions required of a 2.5" cone (effectively less when including the hole in the middle for a tweeter dome) to move enough air at lower frequencies at higher volumes, to below say 250Hz (2 octaves below XO point, so only -12dB; if playing 100dB, mid asked to put out 250Hz percussives at 88dB (round 'electrical' numbers, not taking acoustic roll-off contributions to the end-result 6dB/octave slopes.)).  Ask Rob how many 2.4 coaxes I've gone through, and not due to lack of clean watts and amps!

These numbers were chosen as an example, but isn’t as unlikely as it seems. These are peak levels taken from the listening position (9’) from a pair of speakers playing (2 speakers = +3dB) with some room boost, and C-weighting (accounting for most of the bass). That’s not filling the entire room with 100dB, those are peak readings at a semi-nearfield listening position in a near-ideal room for these speakers. And this represents probably less than 5% of my overall listening, and then for perhaps a side of an album. 95dB peaks would be a more typical *loud* listening session, still infrequent, with *no* 2.4 power handling concerns.

Even then, if that highest level is 105dB at 1m, that’s ~100 amplifier watts (if they’re 87dB@1W/1m), and my amp delivers ~500 watts per channel into 2 ohms with plenty of dynamic headroom. I now better know the limits of the limited midrange, and am comfortable with keeping volume and program material well within their comfort zone. I have never heard my amp compress, harden, and certainly not clip at any volume into any speaker load, which suggests I’m not intent on finding the limits of my amp or any guest speaker!

Rob Gillum tells me in ’destruction testing’ of the similar 2.3 coax development, they typically achieved 115dB SPL steady-state (not transients) before ’it blew apart’ (with 600W Krell monoblocks), and that 100dB peak SPLs from 2.4s should be reasonable in a 3000 cubic foot room (mine is 2500). FWIW, I have never blown a 2.3 coax, even though we have no reason to believe they are a sturdier design. Indeed, Rob says his current rebuilds of these drivers use more-modern adhesives and construction techniques that will increase the robustness of the 2.3/2.4 coax.

Half my coaxes were covered under warranty, and only one exhibited obvious signs of being driven beyond its excursion limit. More typically the lead wires fatigue from years of excursions (well within the driver's (motor + surround) excursion limits) and open the circuit.  Rebuilding a coax every couple years is a whole lot cheaper than buying a speaker today that ticks as many boxes for me as my 2.4s!

I believe that a peer would have been good for him, his products, his company, and its future. But he never found that place. We all make our way the best we can. Thiel Audio carried him pretty well.

This is a very sweet and succinct assessment of Jim and his company.  As only a brother could write for us.

jafant is clearly someone who works in mediation, conflict resolution, marriage counseling, or a college professor.  Or fears discord in his 150 page thread!  It's all good.

Makes me satisfied that Steve McCormack thoroughly modified his already-stable power amplifier to meet the needs of my CS2.3, now using the slightly easier load of 2.4s, and can confirm it has great specs into load in stock form, much better specs now as confirmed by the designer, and sounds great driving them to my own ears, as well as besting 5 other $5-15k modern amplifiers in a all-day shootout last year!  I wish this were so for all Thiel owners (not only those in this forum).

Laughing harder, that you actually *are* in conflict resolution and counseling without my knowing a thing about you!  Goes to show what I pick up on when my wife's a therapist, my neighbor a professional mediator, my father a (former) college professor...

Steve has been a 2-man show running SMC Audio for years since Conrad Johnson took over McCormack production for a few years before dropping it entirely.  So Steve's 'second' career is redesigning and optimizing his 'first career' mainstream amps to demanding customers (like me), and has all the test gear from a lifetime in the business.  I can't speak directly to C-J, but not many amp manufacturers see the relevance of 1 ohm specs, especially when there's nothing flattering about the power output into it for 95% of amps, especially a company whose foundation is tube amps.  All Steve McCormack's testing does is confirm his amps (or at least *my* SMC Audio amp) will remain fully stable into 1 ohm, not oscillate, melt, or blow up.  In fact, my tiny 'signature' box in the upper left is this amp...

jafant, just a (looong) clarification.  Steve made a name among the tweakers post McCormack, but the company in its prime throughout the '90s and early-00s was substantial, offering moderately-priced well-engineered preamps, DACs, phono stages, etc. as well as power amps.  They were brilliantly designed, but brought to an affordable price point with modest chassis build and components.  Which is what makes the SMC upgrades so significant -- the basic design can really shine with top components and clever tweakage.

C-J took over manufacturing of the power amps in the late-90s with some consulting from Steve, but he had already started SMC Audio as his next gig.  The later amps built by C-J never had the same success as the earlier California-built amps.  My top-of-my-head chronology may be a little off, but that's the gist.

No overlap in the sonics between the two companies so far as I can tell.  McCormack amps are purely solid-state with a bit of the good characteristics of tubes baked-in to the design.  C-J has kept the classic tube sound more than other modern tube gear designs, but others here could evaluate that far better than me.  A C-J preamp + McCormack power amp would be a good pairing I'm sure; I use an upgraded Sonic Frontiers tubed preamp.

All McCormack power amps have a 100k input impedance which is fine for any preamp.  EXCEPT for the DNA500, and its monoblock equivalents DNA750 of only 10k, and I believe these to be the only McCormack amps that offer balanced inputs via a phase-splitting transformer (hence the low Zin). 

Most if not all of his amps do have a high input sensitivity for Steve's preferred (?) passive preamp mating, that forces conventional volume pots to work at the very low end of their range with your typical active preamp with 10+ dB gain. 

unsound, thanks for the compliment.  I'm hardly a 'vintage' guy, but my late-production (2001) Line1 SE has been *completely* reliable over nearly twenty years of often daily use.  Of course, I can't leave well enough alone, and it too has been substantially upgraded over the years, to the point where last year it bettered 4 modern $5-15k preamps, though did get 'beat' all-around by a wild-card Plinius solid-state unit.  If our house burns to the ground, the insurance 'replacement' cost for my stereo is going to be far more than what I paid, starting with those CS2.4s...

jafant, these were separate amp and preamp shootouts.  The Plinius power amp compared to my McCormack was a class-A SA-103 (125wpc 8ohms, 220wpc 4ohms), that had comparatively unremarkable sound.  The Plinius Kaitaki preamp vs my Sonic Frontiers was remarkably good-sounding across the board, the only preamp in the shootout to better my preamp in its current configuration.

Just to stay on topic to your thread, the most recent in-house speaker comparison was my 2.4 vs the Dynaudio Confidence C1, a modern, large-for-a-stand-mounted $7500 2-way.  To my great surprise, the Thiels crushed them in every possible aspect.  Even their vaunted Esotar tweeter had no discernible improvement in natural accuracy, smoothness, or micro-dynamics over the 2.4 simple aluminum dome constrained within a jiggly midrange cone.  And the Thiels smoked them in every form of soundstaging, imaging, center focus, wide speaker spacing without loss of center-fill, etc.  Nobody was more surprised than me that such a highly-regarded monitor had nothing - *nothing* - on my 'old' Thiels...

And, by Dynaudio's ad copy, a couple 'tricks' in their crossover to capitalize on their first-order slopes to mimic a sloped baffle and correct the phase response between drivers.  Stereophile's step response plot of the C1 even looks more coherent than most small two-ways.  Good design intentions didn't equal my high expectations I had for their sound.

You're welcome.  As long-winded about audio as I can get, be relieved (all of you!) I'm not transcribing my thorough listening notes here of all the gear mentioned on this forum that I've compared to other stuff, or pre- vs post-modifications, that a career test engineer tends to do!

As an electrical test engineer and lifelong audio geek, I've found Stereophile's measurements rudimentary. For the most part, the testing strategies, reporting, and the depth of analysis hasn't evolved in decades. And they don't tell us a whole lot; today all equipment should measure great to Stereophile standards, and, as mentioned, the attempts at correlating the minimalist measurements with the reviewer's impressions are weak at best.

Looking back at some magazine equipment test reports from the '70s and '80s is instructive. People are right to complain the reviews were 50% or more a thorough reporting on a multitude of valid measurements, and at best a paragraph on the (particularly electronics) subjective sound. BUT the measurements were solid and for the most part far more comprehensive than JA's. The instrumentation and printing of the day didn't allow for as many pictures of graphs, but the authors got the information across, at least to those who could interpret the specs for what they were. A lot of the measurements that had the most relevance are of little use for today's gear: tape decks, tuners, tone controls. But two pieces that were very well-tested that seems entirely lacking today were turntables and phono cartridges, where the measurements generally did do a reasonably good job of reflecting each component's sonics when contextualized with listening comments. Today all vinyl playback gear I've read about is entirely subjective. A frequency response plot of a properly aligned and loaded cartridge is VERY relevant but for one example.

Finally, to the points on this forum, even the speaker testing was often more involved. This was before FFT instrumentation and RTA analyzers, but Hirsch-Houck and CBS labs, among others, used the best techniques they had available to get a handle on loudspeaker measurements, and were clear where they encountered measurement limitations that may not correlate to actual listening. They published measured distortion throughout the frequencies at various levels, often toneburst reproduction and interpretations of it, impedance vs frequency, farfield frequency response with pink noise from various (and combined) positions, and more, that for 30-40+ years ago gave a good idea of how a particular speaker might perform. It doesn't seem this has evolved very much at the consumer level in any publication I'm aware of. Though I rarely read much of the audiophile press with any regularity!

For me, like the rest of us, -- in this forum -- how my Thiels actually sound with proper setup and upstream hardware is far more important than how they measure. But the engineer in me still wants to connect with my chosen gear from the standpoint of thoughtful, solid, and often clever, engineering I agree with, long-term durability, fad-free design, and as far as I'm able to discern, specs that don't reveal shortcomings or shortcuts in the design or execution of the end product.

To quote Michael Fremer, "I'm a Giant Walking Opinion."

@tomic601: "How they measure is hyper important IF the art is to move forward"

I agree 100% with this when it comes to any and all speaker designers, manufacturers and researchers. Most of the real progress has come from individuals and/or companies with both the insight and the access to, or creation of, SOTA measurement gear.  Uh, Thiel for example :-)

My point was that the majority of those who purchase the end-product have little background to make sense of a manufacturer's (usually) minimal published specifications, or interpret the one or two independent lab tests, if they even exist for the speaker under purchase consideration.
  
There's the small minority of us here who do have a clue about the measurements' relevance, but all of us will have to admit they don't substitute for how any speaker sounds in a particular acoustic with all the combinations of upstream hardware.

The seller is taking quite a few rhetorical / marketing liberties to differentiate the SE from the 'regular' 2.4!

My two cents and two thousand words on Spectral products. It seems the only press they get (along with the Berkeley Alpha DAC) is Robert Harley, for better or worse. Goodwins audio outside Boston carry both, and I had a thorough audition of the Alpha DAC in 2012 soon after it first came out, but more to the point here, a good taste of the Spectral DMC 30 preamp (driving non-Spectral amps in this case), after auditioning DACs through a very good ’other’ preamp. On the same material, in comparison, the front-to-rear layering of the soundstage, even on studio recordings, was unlike anything I’d heard in hifi before, combined with a near-holographic stereo image. The top octaves, despite modest digital source material (on a $22,000 dCS CD player), were pristine, precise, super-fast, but entirely natural, and actually seemed on the ’darker’ side of neutral. My initial response was certainly amazement, but that didn’t allow for a more-accurate long-term assessment. As my time in the room (after coming to hear DACs) was finishing up, I couldn’t listen to all I would have liked to, but my impressions were beyond other high-end preamps I’m familiar with, or was .

The company seems pretty low-key, archaic website, and design the best product they can, and leave them alone for years. The preamps have the decent control flexibility I like. It seems the wide bandwidth can cut both ways. There’s certainly no musical information in the MHz, but it does make for perfect transients, even if the high frequency noise screws with downstream amps. My own preamp is spec’d -3dB@>0.5MHz vs Spectral’s 1.5MHz, so I don’t know what frequency the issues begin, but I’m sure there’s more to it. This engineer likes their internal layout, design approach, relevant innovations, product cycle longevity, sane pricing, application of RF instrumentation technologies, true research into semiconductor physics and other details that are taken for granted out of necessity by other high-end designers. I would sure like to audition a DMC-30 at home!

A good friend had Alan Goodwin design a ground-up ultimate listening room within the foundation of his cost-no-object new construction, optimized for 2-channel, but also has 5.1. Spectral DMA-360 amps (and preamp) all around (driving large Avalons), and to my current awareness they’ve been on 24/7 for twenty years without issue. Yes, it sounds amazing, but primarily because of a perfect acoustic, perfect absorption and T60 across all frequencies, and perfect bass loading, something never heard in even a well-treated home room turned listening room.

Playing catch-up for the past month of this forum.
tomthiel: The Philips CD-80 you reference. That was introduced in 1989 (not 1985) for $900. I auditioned it at the time, along with the one-model-lower CD-60 that I bought and used for a decade (later with an Adcom GDA-600 DAC) before getting a deal on a CD-80 that I still use in my bedroom system today. You're right, this was likely the best CDP of its time, overbuilt like a tank electrically and mechanically, with some of the best control flexibility ever. There used to be threads of reworking the CD80 electronics, not as a 'modder' might, but more like Philips might in a "Mk II" to correct and optimize portions of an otherwise brilliant design and execution.

yyzsantabarbara: I've taken renewed interest in your threads here and elsewhere about your Thiel and KEF LS50 experiences, as I just picked up a pair of LS50 Metas to 'supplement' my CS2.4 due to a neighbor hypersensitive to what little bass transmission between condos exists, even with my room and 2.4s optimized for minimal LF bleed. Both the stands and speakers will remain unopened until after the holidays, but will be curious how the two speakers compare based on your observations. I have listened to Blades (1&2) at length, but was never in the market for an LS50-type speaker, until now, and the choice was clear. Though i was less clear as to whether the previous version on closeout, or the meta before this batch sold out.  Are you going Meta?

Finally, I'm going to try again, the first time in years, to sell my mint pair of CS2.3 in maple, complete with the original shipping boxes and manuals. These are later-production models with the already-updated XO and coaxes (the latter replaced at least once). I haven't sold any audio of 'substance' in many years, Audiogon doesn't appear to be what it once was.  How and where would this group suggest I go about selling my 2.3s, and for how much?

@yyzsantabarbara  I've read Meta reviews too, from a consistently slight improvement over the original to a significant technology leap for all box speakers. As I've no experience with the original, I doubt I'll be let down. Like I said, the intent is not to replace my Thiels.

Recent Stereophile measurements clearly show Meta tweeter wired ouf of phase vs original, though no mention in KEF white paper as to why this should be so. You have your share of experience now with out-of-phase HF units, any idea why they might make this change?

I've been very impressed with Blade 2, but admit it would be tough to choose between a known-good-quantity at half price, and a likely very-improved upcoming Meta model, as I had to decide at a much lower price point last week with the LS50. But if it's not about 'smart money' go for the newer Blades: as with the LS50, they'll be tweaking more than just the tweeter rear wave absorption.

I've probably taken this far-enough off-topic by now for a Thiel forum...

yabe1951: others here have heard from me -- some years ago now -- of Steve McCormack thoroughly upgrading my DNA 0.5 to optimally drive my CS2.3s.  A complete success, that was only bettered when I started using CS2.4s as I still do today.  

   The same Plitron transformer in the smaller 0.5 makes for power doubling 125/250/500 wpc into 8/4/2 ohms, absolute stability into 1 ohm, an alleged 60A peak current.  He put in a few other tweaks specific to my 2.3s, as well as his established upgrades he was using at the time for a 'revision B+ Gold' designation.  Steve knows his design cold, and can optimize any of his amps for nearly any preference or load.  My avatar is the internals of the reworked amp, if you can possibly make it out.

   This was completed in 2006, and just recently this amp, at a high-end audio shop, was the best-sounding amp of five modern $5k-$16k power amps, driving a pair of Aerial Acoustics 7T speakers.

   To me this is sort of old news, but your post confirms I shouldn't take what I have for granted!

Actually it took three upgrades to make mine *perfect*, though the first one was just the ’basic’ upgrade of the time. I imagine by now it’s a labor of love, as Steve is past able to retire if he chose. He’s spent decades listening to the best passive discrete parts to mix and match into his existing circuit boards and amp topology, as you say, knowing exactly how to tailor his suit to fit us.

Just a couple examples of ’business as usual’, as part of my middle-of-the-road (non-Thiel-specific) upgrade, he uses 10" of some massive Shunyata Copperhead AC power cable to just connect the rear AC input to the front panel power switch. 1" per channel of some sort of carbon fiber conductor to go from the WBT NextGen RCA input jacks to the circuit board. 4" of Van den Hul high-end speaker cable to go from the output transistors to the Cardas speaker terminals. And that was in 2006 as part of a B-level upgrade!

The beauty is that for some time he *did* the mass production, dealer network, advertising, at least on a modest scale, and enough to have a long-running well-regarded set of products, that were a big bang for the buck as his designs allowed for modest parts to sound ’good enough’, and little money was put into cosmetics.

A good design is still a good design, optimized by the parts and their integration. Just look at all the recycled vacuum tube circuits from the 50s and 60s that are used in today’s top gear with fully modern parts in the signal path and support circuits (power supplies, auto-bias, layout). It would seem he could extract a bit more by further optimizing his circuit board layouts 25+ years later, but that would be a question for Mr. McCormack to assess price vs performance, a calculation he’s always excelled at...

It's this designing for the long haul I find similar to Thiel, and find this approach to be of personal value to me in the components I choose to make up my audio system as a whole.  And other products of note I own...

jazzman7:   The KEF Uni-Q would seem to disqualify itself from this discussion due (at least) to their use of a second-order crossover.  Indeed, the step response plots from Stereophile look nothing like a time/phase coherent loudspeaker:
https://www.stereophile.com/content/kef-ls50-meta-loudspeaker-measurements

Point source, yes, absolutely, at least in their LS50 with no other drivers.  But that's only one non-essential attribute of full-coherence.  Vandersteens' achieve it all without any concentric drivers.  All Thiels except the SCS4 (?) have the wide-bandwidth woofer (and sometimes other drivers too) some distance from their coax mid/tweet.

I just bought a pair of LS50 Metas to supplement my 2.4 due to a hypersensitive deranged neighbor (no lower bass output and lower volume capabilities), but need more time for a thorough A/B to get the true measure of them, as my 2.4s over the past decade have become my reference in my long-term acoustic space. 

I'll report here when I can arrive at firm conclusions, as xyzsantabarbara loves his previous-gen LS50s and his 3.7s, and the Metas are getting serious accolades, many that I can confirm are compelling and actual.