Thiel Owners

To check for the leak, you can gently push in on the woofer and Passive diaphragms at the same time.

I'm very reluctant to try this. Supposedly, dimpled drivers have no measurable or audible effects but . . .

Maybe you can use something with a bigger surface area than fingers yet still softish?

Accuracy certainly is in the mix because these speakers sound about as real as a speaker can reasonably get. Because of that I think they walk a fine line and when people get an unfavorable impression of them i think they have not be set up well. I have never found them to be bright, lean, fat, tubby, warm, cold. They are about as spot on in the middle for me as a speaker can get.

I completely agree. None of the Thiels I've heard (CS7.2, 3.7, 2.4, 1.6) sounded overly bright or cool to my ears (altho' the CS1.6 could be strident at high SPLs with certain female vocalists, I think this is related to the distortion at 1 KHz seen in soundstage's measurements).

Shane Buettner's review of the CS2.4 opined that the midrange had a "slightly-on-the-cool-side-of-neutral sound" compared his reference Vandersteens. But I've also heard the Vandersteen 7 (which is a SOTA-level speaker, IMO), 3A Sig, Treo, Quattro, and I lived with the 2Ce Sig II for 10 years. I have no idea what he meant. To my ears, the Thiel CS2.4SE sounds very neutral, resolved, open, and transparent through the midband. In fact, it sounds superbly balanced at all frequencies. When I listen to performers that I've seen live, I have no trouble whatsoever imagining that they are in front of me.

My conclusion is that people complaining about poor SQ from Thiels have only heard them poorly set-up or with poor-performing amps and/or sources.

That "getting out of the way" quality of Thiels is awfully addictive.

 

Over the last 25 years, I’ve heard speakers from Wilson (W/P 7, W/P 8, Sasha, Maxx), TAD (Reference One and CR-1), Revel (M20, Studio, Salon Mk 2), Avalon (Eclipse, Ascent, Eidolon, Idea), Vandersteen (Seven, Treo, Quatro, 3A Sig, 2Ce Sig II), Aerial (5 or 7?), B&W (DM12, 804), Paradigm (100), Vaughn (Triode), Vivid (Giya G3), Vienna (Klimt), Thiel (CS1.6, 2.4, 3.7, 7.2) and probably many others I’m forgetting. My favorites are, in no particularly order, TAD Ref 1, Vandersteen 7, Avalon Ascent, and Vivid Giya (Thiel CS3.7 and 7.2 just miss the list). Now, these were all in different room with different electronics and over many years of sampling. But I have a good handle on what good sound is.

I’m here to tell you that my CS2.4SEs (driven by Ayre electronics) deliver nearly all of the neutrality, resolution and transparency – my sonic priorities - of the very best speakers I’ve heard. I would have to spend an order of magnitude more money to get significantly better performance in these areas and I suspect there are only a handful of designs at closer price points that can approach or equal the sound I am getting. I suspect the Thiel’s superb coherence is due to similar materials used for all diaphragms. And the resolution and transparency is probably due to the pistonic driver behavior over the intended range of each driver. Jim Thiel did a masterful job to ensure that driver break-up modes were well-suppressed despite the slow roll-off filters.

The only shortcomings I’ve noticed are the lack of low bass (which requires much larger drivers and cabinets and $$$), image density is not quite on par with the best I’ve heard (maybe my placement is not yet optimized?), and the highs are, maybe, not quite as airy and pristine as the very best. Should I be satisfied with getting “only” 90% of a Vivid Giya for $3000?

I think I have my “last speaker” (altho’ I may upgrade the crossovers at some point).

Note that the 2.4 SE only replaced two Solen mylar feed caps with Clarity SAs. Today there are much better caps available today from Clarity, Mundorf and other brands. My personal experience (via consulting for other brands) is that the upper end of the woofer circuit is sonically important, especially with Thiel's first order filters, and that budget is the only limitation to sonic improvement in a high-resolution system. I'll keep you informed as I finalize and test my conversion.

This is great information, Tom! Is there a particular cap you think sounds best for the 2.4? Please keep us (and Rob Gillum) informed of your findings. My understanding of the CS2.4SE is that the Clarity caps only involved the coax feed. Care to share any details regarding the woofer feed?

I suspect that hot-rodded Thiels of many models might make beetle's list.

Yes, I think I wrote this very thing earlier in this thread.

My apology for using the "B" word regarding caps. I meant esoteric high performance, not snobbery.

Yes, I was admittedly nit-picking. "Boutique" is too easily interpreted in different ways. I simply wish you and Jim had used more direct phrasing to indicate the sonic benefits of the more expensive passive parts.

Meanwhile, there is a pair of CS2.4s for sale, $1900, seller rates them 9/10. I kinda wish I had bought something like this and sent the crossovers to Rob Gillum for a full cap upgrade. This would probably result in SQ on par with anything new up to $20K or, even, $30K.

@dgarretson Thanks for the reply. So, are the CS2.4 values available to the public? I will contact Rob Gillum for more info.

Thanks for the post, Tom
I'm very excited to try cap upgrades. Without further information, I'll probably try the latest Clarity caps that will fit in the 2.4 enclosure (which I have yet to open). Probably try some Cardas solder. Probably be weeks or months before I have time to do this,

@dgarretson

Owners of standard CS2.4 speakers may be interested to know that the only internal difference that makes a 2.4SE is the use of ClarityCap SA film capacitors. DIYers can make this upgrade or better by substituting the more recently introduced ESA range.

. I don't have a schematic, but during that time Thiel was purchasing 14uf and 28uf values. They may have been bypassing these with 1uf polystyrene caps. You should be able to confirm this by inspecting the crossover.

Since then we have surpassed SA by two generations-- ESA and now CSA. For that application I suggest CSA/250V or, space permitting, our top CMR/400V model.

You should inspect the board to be sure. The configuration is likely 14uf in parallel with 1uf(=15uf) and 28uf in parallel with 1uf(=29uf). If this is the case, then you could (1) replace the 14uf and 28uf values and leave the stock 1uf polystryrene caps in place, or (2) replace both the high values and the paralleled 1uf caps with 15uf and 29uf.

It is advisable to look carefully at the circuit before ordering anything.

Looking at Partsconnexion and Madisound, I don't see these values from Clarity (or Mundorf), especially as a close-up of the CS2.3SE crossover indicates 630 V. Are Thiel's values a special order?

@tomthiel Thanks for the clarification. This pic
http://www.hifishock.org/gallery/speakers/thiel/cs2-4se-2-thiel/
shows "Jim Thiel Signature" versions SA 28uF 630V and SA 14uF 630V. I cannot see a 1uF cap in parallel. The values on the woofer section are not evident.

I did not see these values online at Madiscound or Partsconnexion. Maybe I didn't look closely enough?

Also, is the crossover accessed thru the passive radiator or bottom panel?

@tmsrdg Thanks for that info. Looking again on Madisound in the Clarity Cap MR 400V (is that enough voltage?), I can get to 28 uF with a 27 and 1 uF in parallel. For 14 uF I need the 12 uF and two 1 uF caps.

But given that I already have the Clarity Cap SA version in the coax, I should start with the woofer section.

Thanks, Mr. Thiel
I might pop one open this weekend and see what's involved as a DIY, see if I can find the values on the woofer section.

@marqmike Thanks for those posts. I think I’ll call Rob Gillum before I proceed. But I do want to look at the crossover to see if it’s a job I’m comfortable with. At a minimum, I’d like to at least take the crossover out at home to save on shipping costs and not risk cabinet damage during shipment.

He intends to develop upgrade kits for any Thiel products to meet demand. Other original Thiel operatives and myself intend to pitch in to help him succeed.

This is awesome! Thanks for posting this, Tom.

I am already spreading the word to Thiel owners.

Good idea. I just pasted Tom's post over at the asylum. We'd be smart to do what we can to support Rob's venture!

@sdecker Wow, that is *super* helpful information. Thanks! Would it be easier to remove the entire boards and replace the caps with the crossovers out of the cabinets? Your post got me thinking that a "real" modder would probably mount the crossovers in an external box (ala Avalon Ascent) to completely isolate it from cabinet vibrations. LOL - that's not me :)

(a 27uF direct replacement and a 10uF || 3uF = 13uF)

From Tom Thiel, Dave Garretson and the image I linked elsewhere in this thread, the CS2.4SE coax values are 28 and 14 uF. Are the 27 and 13 numbers for the original CS2.4 or did you decide to alter the values?

I’d post pictures if I could...

I'm hoping Rob Gillum will offer upgrade kits for DIYers as well as in-house upgrades. Ideally, this would include how-to pics or, even, video links on his website.

Note, my PowerPoints are late-date manufacture from China.

Tom, did *all* the manufacturing move to China? I recall reading years ago that the round cap on the CS3.7 had to be made in China because of quality issues. I didn't realize until recently that the drivers were also sourced from China. And, now, you're saying that the PowerPoint drivers were made in China. What happened in Lexington? Is all of this on the new owners?

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

I gave a short look at this link. How does this guy have time and money to compare all of these, especially given the burn-in time? That top of the line Duelund looks interesting. Some of those sell for north of $800. Even if the OEM price is one-half of that, that would probably add $10,000 retail to put those in a pair of speakers!

The writer quite liked the Clarity CMR and some of the Mundorfs. A DIYer with money could get carried away . . .

@tmsrdg I can't even find the name of the person who compared all of those. What is their experience? What is their system? What are their biases and preferences? IOW, how credible are they and how do we translate those words in ways that help us know which caps should be on our short list?

We get to "know" the hi-fi reviewers by reading their words and comparing that to what we experience when listening to the same product. Not much help for that in the case of these caps. One piece of credible info is that Jim Thiel and his team chose the Clarity SA for the CS2.4SE. Too bad we don't know what they compared it to. Also, Tom Thiel is steering us towards Clarity and Mundorf. One other brand that piques my interest is Cornell Dubilier but not sure if they make caps with the correct values for this purpose.

In the end, I might just go with what Rob Gillum recommends. I'm hoping he'll have a kit with all the parts, schematic, and DIY instructions.

It seems the site ate my detailed response.

Aww, bummer. Sorry to lose what must have been some great info. Re: Mundorf recs from Madisound, were those for Thiels?

I don't know if you can put pics in this thread but you can in the user systems section. Also, audioasylum allows pics.

Thanks for the added info, Tom. I will wait to see what Rob Gillum offers. I don't have time to pursue this now, anyhow. Just toying with the idea. If Mr. Gillum doesn't offer a DIY kit, I will probably start with the woofer feed given that my 2.4SEs already have Clarity Caps on the coax.

I have seen people "upgrade" Thiel hookup wire. I don't buy it. Thiel (lexington) hookup wire is 99.9999%, long crystal, teflon jacket, 3 twists per inch. I've never heard or measured better from any boutique / branded wire.

I trust your experience but I think I would at least try Cardas if I had the time and money.

My hope is to supply subtle information that may not be obvious to all. Crossover networks can be very easily scrambled via changes with unintended consequences.

I suspect I speak on behalf of this community in saying how grateful we are to have you here! I am very much interested in tweaking the last drop of performance out of my CS2.4s. But I have not the expertise, time, or money to try a multitude of mods. Your advice (and, hopefully, that of Rob Gillum) is *greatly* appreciated! I'm hoping you might write more about:

If I were hotrodding an upper end Thiel, I would consider a Teflon bypass in the tweeter feed.

Not anymore than I'm enamored by Thiel! Cardas cables sound terrific and many manufacturers with great sounding products use Cardas wire. YMMV.

Not planning any experiments . . . I hope to upgrade the crossovers exactly one time! Or piecemeal, given that I already have the Clarity SAs in the coax feed. ie, start with the woofer feed, maybe put newer Clarity (or Mundorf) in the coax feed as budget and nervosa dictate :)

From Tom's posts, the best bang-for-the-buck could be to "simply" put top-shelf bypass caps in. I might look at options from Cornell Dubilier in addition to Clarity and Mundorf.

I will continue to check this thread for more info from Tom Thiel and, hopefully, Rob Gillum. In the meantime, there is no doubt that the music in my living room is more clear, immediate, and involving than ever. And I want even more of that!

strat-a-gee article here:
https://www.strata-gee.com/king-thiel-dead-coherent-source-service/

Coherent Source website here: https://www.coherentsourceservice.com/

My "100 MBps" Comcast had a hard time downloading the pic of the CS3.7s!

Woo-hooo! Can't wait to learn more about "hot-rod kits". Crazy that he will honor warranties for legacy models. I hope he doesn't regret that decision.

IME there are very few integrated amps that are really ideal for most Thiel’s.

 
I'm getting superb results with my Ayre AX-5. On one hand, it is the only amp I've heard with the CS2.4SE. But on the other, I'm getting most of the SQ of the very best systems I've heard, eg, ARC Ref 250 driving Vandersteen Seven and Ayre R-series driving TAD Ref Ones. There are only a few systems I've heard that I would swap for mine straight across and all of them are considerably more $$$.

Stereophile's measurements suggest that the AX-5 prefers to work above 4 Ohms.

Hmm, must be all that Cardas wiring ;^)

Looks to me that it behaves very well into a 4 Ohm load. These would be good measurements for an amp *with* negative feedback hiding its problems, never mind a naked zero feedback design. At 2 Ohms, it does start to become "stressed" mostly below 200 Hz. I would probably hesitate to pair an AX-5 with, say, Thiel CS5 or Magnepan 20.

Lining the AX-5 measurements up with the impedance/phase traces for the CS2.4, it appears the most demanding frequencies for the Thiel are a bit higher up in the midrange. Nevertheless, one might wonder how these two might pair. As always in these matters, the proof is in the listening. My ears tell me they work together just fine, thanks. I detect no distortions or other unpleasantness at any frequency or SPL I've tried. YMMV.

If I were to audition and purchase based only on Stereophile's measurements I would not even give Thiels a second look, never mind own them! That upper midrange/lower treble suckout looks fatal! And look at all the hash in the waterfall plot! I'd probably own Revels and Halcros . . . and wonder why I wasn't enjoying my favorite music.

[OTOH, Soundstage's measurements of the CS2.4 taken from 28" further away are among the the very best in their database in terms of flat frequency response and low distortion.]

Welp, I at least we can agree that Thiels are great sounding speakers . . .

I heard the Ayre integrated with the 3.7s

Curious if this was the AX-7 (60 W at 8 Ohm) or AX-5 (125 W at 8 Ohm)?

Stereophile can't or won't measure Thiel's at the appropriate 3 meters.

It makes sense that JA measures from the same distance (ie, standard) for everything but he has to be close (50") using his "quasi-anechoic" conditions to avoid early reflections. Definitively puts first order designs at big disadvantage. Soundstage has a real anechoic chamber and measures at 2 m.

It's all he can do with his limitations and budget. He used to acknowledge the extra problems for measuring Thiels, Vandersteens, et al. but not for many years.

BTW, I'm NOT defending Stereophile!

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?

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 :)

@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.

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!

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%2Bcs2.4

Moreover, 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.

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?

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!

@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).

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).

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.

limited to perhaps 200 Hz and above.

Yes, Thiel's graphs are truncated at 200 cycles:
http://www.vandersteen.com/media/files/APJ%20Files/APJ_6-7r.pdf

Those CS2.3 measurements are superb!

For the bass, I think Stereophile's nearfield technique fills in the gap nicely.

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.

@tomthiel Thanks for the info re: measurements

Here is the link for the article mentioned above: https://www.strata-gee.com/forgotten-thiel/

Curious to see if Tom has any specific suggestions for hot-rodding the 2.4 SE

@tomthiel I am able to find (at Parts Connexion) Clarity CSA parallel combos that will give me the CS2.4 capacitance in the coax (14 and 28 uF) and woofer feeds (33 uF). Reading this review of capacitors: http://www.humblehomemadehifi.com/Cap.html it is tempting to match the Clarity with Mundorf (writer suggests 90% Clarity and 10% Mundorf). But I can’t get the exact Thiel values with Mundorf combos. For example, I can get a 22uF CSA and and 5.6uF Mundorf. How critical is it to get the exact capacitance value, especially given that these are rated +/- 2-3%? It is possible to add a third in parallel, eg, 22 + 5.6 +0.33 = 27.93. Do you recommend adding the third capacitor to get closer to 28 uF?

Also, what are your thoughts on adding 0.01 uF bypass? I might try adding a Dueland or Cornell-Dublilier 0.01 to my existing SA in the coax feed - seems like a potential best-bang-for-the-buck mod - but not if you think that’s a bad idea.

Thanks for the helpful reply, Tom!

I would appreciate you modifying one speaker and perform whatever comparative tests you can between old and new.

I should buy a pair of standard 2.4s and mod those first, enabling the best comparison. My wife would *love* that! hehe - I wonder if there's a market for modded 2.4s?

I *am* serious about this, and need to decide among the many combos. I could go straight CSA for about $375. I could go CSA/CMR for about $610 or I could go CSA/Mundorf SGO for about $800. Or I could put CSA on the woofer and spend more on the coax. Some of these combos require a 4th cap to get the correct value. Life is too short!

I would appreciate you modifying one speaker and perform whatever comparative tests you can between old and new. We can build a knowledge base here on the forum for the benefit of all, including yet to be identified upgraders everywhere.

Thinking about this more, I'm sure I have Beatles or Sinatra or the like in mono, so maybe not so hard to compare as I first imagined. Probably need to let the new caps burn in for a couple hundred hours before comparing. I'll certainly report back, probably won't find time until April or later to do the surgery.

Rob might have an upgrade path for those CS7s

Upgrading those to 7.2 and modding the XO could make those *really* sing! In my room, the speakers are 7' from the front wall . . .

I like the CSA +, + with the 0.33 being a teflon or other ultra-grade cap if possible. Ultra bypasses are far less important on the woofer, put more value on the coax feeds

Thanks for this, Tom!

I have yet to remove the passive radiator to take a look for myself but the pics I've found on the 'net suggest a problem I hadn't considered - there might not be enough room for double bypass on the coax feed. The extant 14 and 28uF caps are ~49 and ~65mm D, respectively. Replacing these two with six caps might not fit even if I stack them on the resistors and each other (BTW, are there sonic gains to be had by upgrading the resistors?).

It's tough to get the Thiel values (14 and 28 uF) in combos of two. Clarity makes a 27uF CSA, which would combine nicely with a 1uF ultra cap, but I can't find a retailer. I can get 18uF CSA and combine that with either 10uF CMR or Mundorf Supreme. The 14uF is tougher. I can get a 12uf MR and combine that with a 2uF CSA – is it deleterious or non-beneficial if the lower capacitance cap is lesser quality? Going with Mundorf mandates a double bypass, eg, 10uF CSA + 3.9uF Supreme + 0.1uF Supreme.

There appears to be much more room to replace the single 33uF woofer cap. Plenty of room to replace these with 15+18uF CSA or 33uF Mundorf Supreme EVO or, most inexpensively, 33 uF SA.

Obviously, I can’t make any purchase without first looking at the boards myself and seeing how much room there is.

7' from the wall is a great luxury. Do you also have a high ceiling? Ceiling bounce is a real issue.

I'm kidding about getting the 7s. The 7.2s were close to the best I've heard but I'd rather tweak out these 2.4s (for now!). My room is vaulted with the tall end at the listening position. I had fabric on the ceiling for a few years to reduce reflections but took it down to wash the dust and decided it really wasn't helping to a worthwhile extent. I think I'm saved by two openings on my rear wall including a ~5'W x 4'H just above my head behind me.

XO layout space is a real issue that will have to be engineered as we go.

I think i can fit the double bypass options by stacking the caps on each other and on the resistors. I will cut the extant leads close to the caps to make sure all the leads can tie together. Is it a no-no to place caps on the coils? I think this 3-D arrangement would extend the XO profile about 4 cm further into the cabinet.

the smaller values must be higher quality to get improvement.

Thanks for the warning!

I would suggest a 32 ± SA bipassed with 1uF ± teflon as a high likelihood of success.

Can't get a 32uF in a single cap. Could do a 20uF SA + 12uF CSA + 1uF CMR or Mundorf. What do you think about adding an ultra 0.01 to the 33 SA?

I would imagine outboard XOs to reduce size / layout constraints and take the XO farther from driver EMF and microphonics.

In an earlier post you warned about taking the XO outboard because the values are dialed-in for the within cabinet environment. Do you have a rule-of-thumb for how to modify for outboard?