Acoustic Sounds

Solen Electronique

Sasandu Tx Loudspeaker

By: John Marks

August 24th, 2023



SB Acoustics x Solen: Sasandu Tx Loudspeaker

EXCLUSIVE First Review

When Robert Schumann wanted to tell the world how impressed he was by the young Johannes Brahms, Schumann published words to the effect of, “Hats off, ladies and gentlemen!” That’s exactly the way I feel about Solen Electronique’s fully assembled and tested (and slightly tweaked) version of SB Acoustics’ top-of-the-line floorstanding 3-way (but with twin woofers) loudspeaker kit, the Sasandu Tx (for TeXtreme). (The sasandu is a traditional Indonesian musical instrument.)

 The Bullet-Point Reasons Why It’s “Hats Off!” Time for the Sasandu Tx:

 • Revolutionary State-of-the-Art cone-and-dome woofer and tweeter technology;

• Danish driver design and engineering, with Swedish high-tech driver materials;

• Distinctive, sophisticated, high-quality cabinets, fabricated and finished in Indonesia;

• High-quality crossover design, with “boutique” parts;

• Tweaked, assembled, and tested in Montréal, Canada (in the NAFTA Zone); and

• Class-Leading Value for Money

 The bottom line is that Solen’s assembled-and-tested “Sasandu Tx Finale” kit will cost United States buyers in the Lower 48 states CA $11,999.00 the pair (which at the time of this writing is USD $9,450.00 the pair), shipping included.  (Erm, for some famous brands, that’s “2-way monitor” money.) That “Basic” shipping consists of delivery onto your driveway or sidewalk. (Solen provides a 5-year Limited Warrantee, with the usual exclusions.)

 “White Glove Delivery,” which consists of in-home delivery, unboxing, and positioning the loudspeakers in your chosen position, is available, but at extra cost. The extra cost will depend on where you live and, most likely, how many staircases are involved. Phone or email Solen for a quote. (Connecting your new loudspeakers to your stereo system is by you.) Furthermore, crossover upgrades and optional paint finishes are available at extra cost.

 For that outlay, you get State-of-the-Art driver technology, as is also found in loudspeakers costing upwards of $30,000 the pair, and a Frequency Range of 32Hz to 32000Hz.

For comparison, if you bought the driver kits and crossover parts and empty cabinets from Solen, and if you did all the assembly work by yourself (including hooking up and soldering 24 crossover components per speaker), the kit price would be $6,100 dollars per pair, plus shipping. That is a bargain; but only if you are a very experienced D.I.Y. loudspeaker builder.

If you ask nicely, Solen will assemble and test the crossovers for you. That assembly labor will cost around $300 the pair (over and above the cost of the crossover components), plus shipping. Regardless, I think that buying the fully assembled and tested loudspeakers is a “total no brainer.”

 If Something Seems Too Good to Be True…

 “How is Solen’s product pricing for the ready-to-play Sasandu Tx even possible?” you well might ask. Good question!

Sinar Baja Electric/SB Acoustics of Indonesia is one of the largest OEM manufacturers of loudspeaker drivers in the world. Their products range from very affordable small full-range drivers for non-traditional uses, to “Boutique Quality” high-tech woofers, midranges, and tweeters intended for the High-End audiophile loudspeaker market. SB Acoustics uses the name “Satori” for its highest-end drivers.

Of particular interest are the woofers, woofer-mids, and tweeters made from Thin Ply Carbon Spread-Tow Fabric, which SBA markets under the name TeXtreme. I think that it is fair to say that SB Acoustics is “lower-case ‘c’ ‘catholic’” in its driver-engineering approach. SBA not only makes tweeters with domes in fabric, TeXtreme, and Beryllium. SBA also makes its own Air-Motion-Transformer(!) tweeter, as well as a 2.5-inch fabric-dome midrange.

SB Acoustics has provided custom-made drivers (or, has supplied important driver subcomponents, such as woofer baskets) to US high-end companies such as Aerial Acoustics and Wilson Audio Specialties. SB Acoustics has also made complete loudspeaker systems for OEM customers such as JBL.

I find it fascinating that early on (the company was founded in 1981), SB Acoustics sold OEM drivers to Radio Shack. How about that? So, perhaps those small Radio Shack loudspeakers that “Sam Tellig” raved about in Stereophile magazine long ago, were based on Indonesian drivers.

 An SB Acoustics company-profile article from 2016 is here. Since the year 2000, SB Acoustics has had its own woodworking operation. All told, SBA has 2,200 employees. By the way, although SBA’s factory is in Indonesia, the actual driver engineering and design is carried out in Denmark (of all places). The acoustic design of the Sasandu Tx (including crossover) is by Ulrik Schmidt of Danesian Audio Denmark.

So, from the first crack of the bat, when SBA offers a basic loudspeaker kit or a kit with cabinets (or, when Solen offers a fully-assembled loudspeaker), those woofers and tweeters will cost less than buying them from a third-party company such as SEAS or ScanSpeak. The same holds true for Solen, respecting capacitors, inductors, and resistors—Solen manufactures all those, both in France and in Canada. Obviously, avoiding “triple-tier, brick-and-mortar retail” markups is a large part of the favorable pricing equation. Another cost-avoidance factor is that neither SBA nor Solen advertises in the traditional “consumer” print magazines about high-end audio.

Lower selling price is the benefit of not going through traditional brick-and-mortar audio dealers. The drawback, however, is that unless you live within driving distance of Montréal (or, unless you are willing to make a special trip—which is something I strongly recommend—Montréal is a charming city!), you can’t easily “try before you buy.”

 (Metaphorically) Tearing Down the Sasandu Tx

 So, what are they made of? Are they really made of “Sugar and Spice, and Everything Nice”?

 The Drivers

The heart and soul of the Sasandu Tx loudspeaker are its TeXtreme Thin-Ply Carbon Diaphragm drivers: two identical woofers, a midrange, and a dome tweeter. MetaModalTX “Spread Tow” Thin-Ply Carbon is a proprietary high-tech fabric material developed by Sweden’s Oxeon group for many applications, including Formula 1 auto racing, and aerospace use.

 Oxeon spun off a separate subsidiary, Composite Sound to serve the loudspeaker industry. Composite Sound sells ready-to-incorporate TPCD diaphragms. The “Thin Ply” part is not a hollow brag. Some Thin-Ply Carbon driver diaphragms are less than half a millimeter thick! (A United States dime is 1.25mm thick.)

TPCD technology offers not only lightness and stiffness. Its “basketweave” construction enables an optimal balancing of circumferential stiffness with radial stiffness. That distributes the usual large symmetrical resonant modes as smaller, individual modes. The result is minimized diaphragm breakup, and enhanced pistonic motion. (The exact makeup in terms of composition and weave of the cones and domes Composite Sound provides to SB Acoustics is the result of collaboration between the two firms, and those cones and domes are exclusive to SBA.)

Another benefit is self-damping, which avoids the out-of-usable-bandwidth frequency-response peaks often seen with metal and ceramic drivers. More information about Composite Sound can be found here.

The Sasandu Tx employs two SB Acoustics Satori 7.5” MW19TX-8 TeXtreme Cone Woofers in a ported enclosure. These woofers have an effective piston area of 158cm2 each; linear voice coil travel (peak-to-peak) of 13.4mm; moving mass of 15.6 gr.; a resonant frequency of 33Hz; and a sensitivity of 90dB.

I calculate the MW19TX-8’s Agility Factor to be 75.76, which is the second-highest such metric I have ever worked out. (Agility Factor is a “unit-less quantity” or metric.) I think that the woofers’ Agility Factor of 75.76 explains a lot about the Sasandu Tx’s remarkable sense of quickness, and its resolving power when it comes to timing.

Satori 6" MW16TX-4Satori 6" MW16TX-4 TeXtreme Cone Woofer-Mid


The Sasandu Tx’s midrange is a SB Acoustics Satori 6” MW16TX-4 TeXtreme Cone Woofer-Mid. Unlike the two 7.5-inch woofers, this woofer-mid is installed in a separate sealed-box sub-enclosure. This driver has an effective piston area of 119cm2; linear coil travel (peak-to-peak) of 12mm; moving mass of 12.6 gr.; a resonant frequency of 29Hz; and a sensitivity of 90.5dB. I calculate the MW19TX-8’s Agility Factor to be 49.

In a “textbook” .25-cu.ft./7-Liter sealed enclosure, this woofer-mid would be expected to have a -3dB point at 89Hz. In this design implementation, Danesian has opted for an .63-cu.ft./18-Liter sealed enclosure. Regardless, the dual woofers cross over to the midrange at 400Hz, which I infer is in the service of the Sasandu Tx’s impressive 108dB Max SPL, and vanishingly-low midrange distortion. (I heard none.)

At 2800Hz, the midrange crosses over to the Satori TW29TXN-B-8 TeXtreme Tweeter, a 29mm dome. For starters, the TW29TXN-B-8 has a moving mass of circa half a gram—.49 gr., to be exact. Interestingly, the Beryllium-dome version of this tweeter’s moving mass is only .03 of a gram lighter, while costing 49% more. Wow.

Now you know why Thin-Ply Carbon technology has grabbed the attention of so many loudspeaker designers. In this implementation, the Sasandu Tx’s tweeter is claimed to have extension to 32,000Hz.

The loudspeaker industry has begun to take note of TPCD technology, and to get with the program. Brooklyn-based Ex Machina Soundworks offers three sizes of self-powered (active) studio monitors, all of which employ a unique coaxial midrange-tweeter driver set that is custom-made for them by the prestige Norwegian loudspeaker driver manufacturer SEAS.

That coaxial array is made up of a Composite Sound MetaModalTX midrange cone with a MetaModalTX dome tweeter at its center. One cool aspect is that the midrange cone also functions as a waveguide for the tweeter. SEAS recently announced its first two generally-available TPCD drivers, a 5.25-inch woofer-midrange, and a 29mm dome tweeter.

Wisconsin-based Perlisten Audio is a relatively new company (founded 2020), but it was started by two very experienced loudspeaker-industry professionals. I can’t remember any other loudspeaker manufacturer whose product received a Class A recommendation from Stereophile magazine so early on (2022). Perlisten designs and builds its own drivers, obtaining unfinished MetaModalTX fabric from Composite Sound.

Another company that designs and builds its own drivers from MetaModalTX unfinished fabric is Maine-based ultra-premium builder Rockport Technologies. Rockport was the pioneer in using Thin-Ply Carbon in their drivers, back in 2011—that’s a nine-year head start on everybody else.

Rockport’s TPCD implementation is distinctive in that they use two layers of Thin-Ply Carbon fabric to sandwich a layer of Rohacell foam. Rockport’s entry-level loudspeaker has a US MSRP of $38,000.

I think that that data point puts the Value Proposition of the Sasandu Tx in its proper context.


ex machina soundworks



Rockport Technologies


The Cabinet

SB Acoustics offers its cabinet and crossover plans free of charge.


I think “sophisticated” is the best word for the ready-to-stuff cabinets that SB Acoustics offers as an option for Sasandu kits. There’s a touch (but not much more than that) of Rockport Technologies’ cabinet design language in the overall look.

The swept-back, tall, narrow-but-deep cabinet design hides its bulk very effectively. But, once you walk around it, it will be seen as impressively large. The cabinets are 43.3” tall x 9” wide (at the front) x 18.9” deep. (The width of the cabinet narrows from front to back.) Each assembled loudspeaker weighs approximately 70 pounds.

As I just said, this is an impressively large loudspeaker. Really, if the cabinet’s body were upright and at vertical right angles to its base plate, “Sunrise” from 2001: A Space Odyssey’s Also Sprach Zarathustra just might start playing inside your head. (Complete with chattering primates.) And, with dimensions that are not totally far off from the proper “2001” Monolith proportions. Which are 1 x 4 x 9, if you were curious.

The Sasandu Txes arrived safely, each double-boxed, and with foam inserts custom designed to hold its unusual form in place. Shipping weight was about 100 pounds each. SB Acoustics includes round, individual-driver grilles with magnetic fasteners, which I left in their boxes.

I should note that a Sasandu kit is also available at lower cost, with Egyptian Papyrus woofers and midrange, and a Beryllium tweeter. The driver cutouts in the cabinets are the same.

The Sasandu cabinet sits on a plinth, and tilts back at 7 degrees for time alignment. Additionally, the corners of the baffle board (front panel) are progressively beveled toward the top of the cabinet, in the interest of minimizing tweeter diffraction. Over and above the separate sealed midrange sub-enclosure, there is much attention to internal bracing.

The cabinet is acoustically damped throughout, on almost all internal surfaces, by 1.5-inch polyester acoustical batting. Luckily for would-be D.I.Y.’ers, the empty cabinets, as purchased from Solen, already have all the finicky work of fitting the acoustical batting done. The ports are also already installed. Black Satin is the standard cabinet color. Black High Gloss, White Satin, White High Gloss, Red, and Orange are available by special order.


The Crossover


Sasandu Tx crossoverThe Sasandu Tx’s crossover is moderately complex, with 24 elements. There are five elements in the woofer section. In the tweeter section, there are two elements (a resistor and a capacitor), in series in the signal path between the amplifier and the tweeter. The other five tweeter elements are in parallel, presumedly for evening out the tweeter’s frequency response, and setting the level relative to the woofer.

The bulk of the complexity is found in the midrange section where, as one might expect, the midrange driver is connected in Reverse polarity. It certainly looks like a lot of time and effort went into this crossover design.

When buying a kit or a completed loudspeaker from Solen, you can discuss crossover-part upgrades. Indeed, you could go Whole Hog and order your dream crossovers first, and then have the crossovers sent out for Cryogenic Processing, and then returned to Solen for incorporation into your finished loudspeakers.

You could also order factory-terminated lengths of Cardas Twisted-Pair hookup wire. Cryo those, too! Of course, buy a big bag of Mongolian Longhair Cashmere Carded Sheepswool, while you are at it!

Where was I? Oh, you can also buy the Sasandu Tx basic driver kits, the optional empty cabinets, and assembled crossovers from Madisound. Madisound will also discuss crossover-part upgrades with you. But, as far as I know, Madisound does not offer completely assembled and tested Sasandu Tx loudspeakers.

In the spirit of Full Disclosure, I should mention that after their critical listening, the engineers at Solen decided that the levels of the Sasandu Tx’s midrange and tweeter, relative to that of the woofers, had to go down, just a little. A matter of less than 2dB. I am confident that that was a valid decision. But I am equally confident that Solen will work with their customers in the event any additional (and, feasible) tweaking is desired.


 In my small-ish listening room, I set the Sasandu Txes up about six feet apart (center to center) and about seven feet away from my listening position, starting with them completely toed-in, and experimenting from there. I set up a Tibetan wool-felt-ball rug on sawhorses, to cover the front of the fireplace, with its glass doors.

Associated equipment was my Apple laptop computer, a JVC DVD player as a CD transport, Bricasti’s M3 DAC, and a VTV stereo amplifier that is based upon Purifi’s plate-amplifier module. I used an Esperanto Audio SPDIF cable, a WireWorld USB cable, and balanced interconnects and solid-silver, air-dielectric loudspeaker cables from ArgentPur Audio.

As per my usual custom of decades’ standing, I started with the first two tracks from Stereophile’s Test CD 2 (the same tracks are also on Editor’s Choice), the Channel ID and Phasing tracks. That’s to protect me (and you) from setup errors.

First off, these are very efficient loudspeakers! I had set the volume where I usually have it set for these test tracks, and I got blasted with sound a bit. I had to turn the volume down, by about 6dB. This is not a loudspeaker whose lack of bass gets really frustrating, when you listen at lower volumes.

Secondly, my overall impression was of effortlessly rich and full sound. John Atkinson’s fretless Fender electric bass was impactful, but not overdone. Importantly, Richard Lehnert’s speaking voice, as he announces the tracks, lacked the annoying sibilance I have usually heard.

One important test for me is first to listen to the Phasing track’s out-of-phase voice and bass, and then listen to the in-phase. I then assess how major a difference there is. Up until now, the Champion on that test track has been the Vivid Audio K-1 loudspeaker. That Vivid model (I think this is true for the entire line) has midranges and tweeters that are formed from the same proprietary alloy; and both tweeter and midrange are in the shape of a catenary cross-section, rather than a hemisphere.

Well, although the Sasandu’s midrange is not a dome, its tweeter and midrange are made from the same material. Perhaps that is what enables them to create such a remarkable perceptual difference between in- and out-of phase. I’d call it a tie with the Vivid K-1.

My personal Loudspeaker Guru is Winslow Burhoe (Winslow, among other accomplishments, invented the inverted-dome tweeter). One of his precepts is that pink noise is a largely under-appreciated diagnostic tool. Winslow says that pink noise should sound like a “waterfall.”

OK. So now I get to confess to one of my (I hope, rare) engineering goofs.

While I was working on a loudspeaker-design project, I needed to burn in new drivers. So I created a one-hour pink noise .wav file using the Amadeus Pro II Digital Audio Workstation (DAW) computer program.

Mistake. The resulting pink noise was OK for burn-in. But when Winslow listened diagnostically, he was not impressed. We both assumed that my design was a bit off. Wrong.

It turns out, the sound file created by Amadeus Pro’s Pink Noise Generator was more “Beige” than Pink. I then went back to the John Atkinson Pink Noise from Test CD 2 and Editor’s Choice. While not a “Night and Day” difference, there was a very noticeable difference. Lesson learned. And, all praise and honors to JA.

So, playing John Atkinson’s Pink Noise over the Sasandu Txes, first of all, the sound was truly waterfall-like. Second, and I hereby nominate myself for the Nobel Prize In Literature for “The Nerdiest Thing Ever Written in a Loudspeaker Review,” the Sasandu’s upper midrange and treble reproduction did not impart any of the dreaded “Cupped-Hands” coloration to the pink noise.

That, I assure you, set me back on my heels. I had heard so much “Cupped-Hands” coloration on pink noise over the years, that its sudden absence was really quite a jolt.

By now: Are you getting the idea that I have concluded that the widespread availability of “affordable” TPCD drivers is going to be a genuine “Game Changer” in high-end audio? Yes? Thanks!

By the way, I also want to mention that on the JA Pink Noise over the Sasandu Txes, I thought I heard a slight mid-bass emphasis. Nothing to get concerned about, but it was there, and I will come back to it.

Moving on, to Ella Fitzgerald’s Cole Porter “Easy to Love.” Wow. Never heard it better. It turns out you have to have a great playback system to hear how surprisingly good, as a recording, this 1956 monophonic track is. The Sasandu Txes did the best job ever, of untangling Ella’s voice from the piano, guitar, and bass. Her voice itself was centered, present, and wonderful; her breathing was clearly audible. Furthermore, the little moment when she turns off-mic and swallows sounded like she was right between the loudspeakers.

I have put up a 12-track Qobuz playlist of demo tracks I frequently use. (Obviously, this is not an all-inclusive list.) Ella’s “Easy to Love” is there, along with four other female vocals, some male vocals, and a couple of group vocals.

Better yet, here’s an article with that playlist with background, explanations, and hints as to what to listen for: all 12 tracks will take only about 47 minutes. One reason you owe it to yourself to check it out is that one of the tracks is the single greatest totally-unknown Female Vocal in existence. IMHO. Really.

The next track up was Christy Moore’s “So Do I.” That track, for ages, has been the single most relied-upon setup track of Peter McGrath, of Wilson Audio Specialties. That song is from the Irish Singer-Songwriter genre, and mostly acoustical. But I also suspect there are some synthesizer “strings.”

 Peter says:

 The fact of the matter is that, despite being close-miked, there is little proximity effect in Christy’s voice on this track. What I find most useful in the recording is that his voice excites the most common and troubling room resonant modes that one encounters in most setups, when the loudspeakers are not positioned as well as they can be. The goal is to reduce the room-induced “quasi proximity effect,” which occurs in the 80-160Hz region. 

In fine-tuning the setup of a pair of loudspeakers, Peter McGrath moves the loudspeakers in increments as small as half an inch. He then listens to how the room’s resonances compliment or detract from the naturalness of the sound of Moore’s voice.

Listening to “So Do I,” my first impression was that the Sasandu Txes provide a just about perfect bass foundation for the song. You will never mistake the Sasandu Txes for little 2-way shoeboxes.

My next impression was that, again, the vocal sibilance I had become used to hearing was absent, but with no sense of a muffled or dull coloration. Moore’s voice sounded front-and-center; but also, intimate and conversational. There was also about the amount of characteristic male chest resonances that you would expect to hear.

It also became apparent that these loudspeakers just love plucked strings, from Late-Renaissance lutes and theorbos to modern steel-string guitars. On “So Do I,” the guitars sound dynamic, but more toward the warm and mellow end of the spectrum, never steely or pointed. Speaking of guitars, “So Do I” is probably, overall, a better demo track than my “Beloved of Ages” Gordon Lightfoot “If You Could Read My Mind,” which the Sasandu Txes aced.

The third track of my Qobuz demo-track playlist features Italian baritone Franco Vassallo singing “Ideale,” an art song by F.P. Tosti (who was a fascinating character). “Ideale” was a big hit for Enrico Caruso. Therefore, Track 2 of my Qobuz playlist is Caruso’s 1906 recording, just for comparison.

Vassallo’s is a fantastic recording, and the Sasandu Txes present Vassallo’s voice as both larger than is usually the case, and also farther back into the soundstage. The articulation of Vassallo’s initial-consonant trills or rolls was remarkable. This is also a truly exceptional recording of the piano.

Well, after one really great Italian singer, did I have any choice but to let my playlist play on, to Frank Sinatra’s “I’m a Fool to Want You”? And here, I experienced a bit of a revelation. If you don’t know Sinatra’s 1957 album Where Are You, I am not surprised, because it seems to be under-appreciated.

The original recording sessions were, except for one track (“I Cover the Waterfront”), recorded in stereo as well as mono. The first LP release was mono. The later stereo LP release omitted the recorded-only-in-mono track.

 I have the MFSL mono SACD. Which, now that it is out of print, goes for quite a pretty penny on eBay.I suspect that the streaming versions are also monophonic, so that there is not an obvious soundstage change between tracks 2 (“The Night We Called It a Day”), and 3 (“I Cover the Waterfront”). Therefore, we have Sinatra, in his prime, recorded Larger-Than-Life with one microphone, with Gordon Jenkins’ orchestra recorded in Multi-Microphone Mono Mixdown.

Over and above this having been the best playback I have ever heard of “I’m a Fool to Want You,” the phantom mono center image of Sinatra’s voice was huge. Just plain huge. I then began fitting together the pieces of that puzzle.

These loudspeakers are efficient, and unusually coherent. The integration of the midrange and tweeter is unsurpassed in my experience. Furthermore, the separate sealed-box midrange sub-enclosure makes for additional midrange definition. However, equally important, is that the woofers’ Agility Factor of 75.76 means that we have some seriously quick bass going on.

And please also remember that the woofer-to-midrange crossover frequency of 400Hz means that not only is the midrange driver being spared from having to do some heavy lifting all the way up, past Middle C. The woofers are also contributing their power and speed up past the middle of the piano keyboard, which is well into the range of most male voices.

I previously mentioned the phenomenon of “characteristic male chest resonances.” If it helps you visualize or imagine it, just think of the typical deep, honey-toned, ingratiating FM Classical male disc jockey’s voice.

BTW, there’s a laugh-out-loud-funny murder mystery set in an on-the-rocks FM Classical station: K.K. Beck’s We Interrupt this Broadcast. Highest recommendation.

Now, if an adult male sings or speaks somewhere around Middle C at 262Hz, his chest cavity will resonate at about half that frequency, i.e., 131Hz. Characteristic male chest resonances run from about 80Hz to 125Hz or 150Hz.

I then remembered that on pink noise I had heard a little something extra going on in the mid-bass. That reminded me of the famous euphonic “BBC Hump” as is found in the original LS3/5A, and many of its descendants. Perhaps it was an unintended consequence of slightly reducing the levels of the midrange and tweeter, or perhaps it was just “baked in the loaf” of the drivers’ performance or the cabinet design.

I want to stress that I am no more upset by the slight mid-bass emphasis I am hearing—some of which, in any event, might be owing to the loudspeakers' placement in my small-ish listening room—than I am by the presence of a "BBC Hump" in any given shoebox monitor.

Please don’t let that little thing keep you from seriously considering these wonderful, bargain-priced loudspeakers. Furthermore, John Atkinson has published plenty of frequency-response graphs with larger bumps in the bass; and some of them are lower down.

Rounding out my listening: I did a serious deep dive into Guilty Pleasure Tracks such as Gino Vanelli’s “I Just Want to Stop” and Sade’s “Smooth Operator.” And how do you like them apples?

In contrast, there’s no guilt associated with Roxy Music’s “More Than This” and the title track from Avalon. Pierre Boulez’ Vienna Philharmonic Mahler 5, as it should be, was a study in conflict and chaos, followed by a string-drenched love letter. David Willcocks’ world-première recording of Vaughan Williams’ An Oxford Elegy showed off the Sasandu Tx’s great soundstaging capabilities, with the cor anglais far toward the rear.

I don’t usually go looking to play recordings with big bass-drum hits. However, I do have a few such tracks I do bring out as test or demo material… but only rarely. One is from the dawn of the CD era, and the other one is much newer.

The old track is the first cut of Telarc’s Soundstream digital Frederick Fennell wind-band program of Holst, Handel, and Bach, with the Cleveland Winds. The LP version was from 1978; the CD was released in 1983.

Holst’s Suite No. 1 revolutionized military band music, and it remains one of the most-performed pieces in that genre. In the early days of CD, I used to queue Fennell’s version up to show off the CD medium’s quiet background and wide dynamic range, playing my Fried C3/O2 satellites/woofer-modules combinations very loudly.

Well, the Sasandu Txes were almost the equal of the Fried woofer modules, each of which had a 10-inch woofer in a transmission-line enclosure of more than 100 liters. I was startled by the final thwack. Which should have not been a total surprise, given that each Sasandu Tx’s twin SBA 7.5-inch woofers combined, have a greater frontal (“pushing”) area than one 10-inch woofer does. (88.3. vs. 78

My other “Big Bass-Drum Thwack” test track is the last section (“Dramatic – Tragic”) of Roy Harris’ remarkably concise one-movement Symphony No. 3 (1939). Today, I think that Harris’ greatest symphonic achievement qualifies as a Neglected Masterpiece. It is very approachable but never trite, and a performance takes less than 20 minutes. The opening is almost an orchestral version of Gregorian Chant in its one-line starkness; what follows could be imitative of Organum. By the end, perhaps there is even a bit of Americanized Wagner in the harmonic tension.

Reportedly, Harris’ Third Symphony’s opening is based on a violin concerto that Jascha Heifetz commissioned from Harris, but then rejected. That was Heifetz’ loss, is all I can say. Neeme Järvi and the Detroit Symphony turn in a splendid job, in exceptional sound (recorded 1996).

Of course, in addition to the Thwackery, the Sasandu Tx was very tuneful in the bass, with excellent pitch definition, as showcased by bassist Christian McBride’s melodic lead on Jane Monheit’s Fats Waller “Honeysuckle Rose,” from her 2004 studio album Taking a Chance on Love.

Another wonderful bass track (albeit synth bass, I believe) is Jamshied Sharifi’s title track from “A Prayer for the Soul of Layla.” Sharifi was educated at MIT and the Berklee College of Music. He later conducted the MIT Festival Jazz Ensemble, and taught Music Synthesis among other courses at Berklee. He then left off teaching at Berklee to concentrate on film and television scores. His Mideastern-influenced multi-instrumental album “A Prayer…” is something you should check out.

 Summing Up:

 Some time ago, one member of my informal “Golden Ears” listening panel bought a pair of Vivid Audio loudspeakers, after hearing one or another of the review samples I had had in. (Note, he bought from a dealer.)

Therefore, I was knocked over with a feather when he listened to the Sasandu Txes and said that he thought that, on balance, as between his Vivids and the Sasandu Tx, the Sasandu Tx had the better tweeter.

Well! He’s not quite ready to sell his Vivids. But, he was intrigued to learn of the existence of SB Acoustic’s Ara Tx two-way, which, I imagine, if you ask nicely, Solen might build a pair of, just for you.

Another Golden Ear friend, who spent many years listening to the various symphony orchestras in London, and who is also an amateur pianist, is so tempted to buy the Sasandu Txes.

I would expect that a loudspeaker that has so much going for it in the way of high-quality components and engineering, and which sounds so good, would cost about $20,000 (or, maybe $19,000?) in a brick-and-mortar stereo store. But I don’t want anyone to roll their own personal dice on the issues of, my setup and my listening preferences, versus theirs.

Therefore, if you are seriously considering the completely assembled-and-tested Sasandu Txes, please also give serious consideration to taking an adventure trip to Montréal to audition them.

That’s in part because I certainly understand why, with the retail pricing cut so close to its costs, Solen shouldn’t have to provide a Money-Back-Guarantee. (By the way, they do have a symphony orchestra in Montréal, and they also have a spiffy new concert hall. Go hear them!)

In any event, you read it here first:

The widespread availability of “affordable” Thin-Ply Carbon loudspeaker drivers will be a genuine “Game Changer” in high-end audio.


Manufacturer Information

Solen Electronique

3940 Boul. Sir-Wilfrid-Laurier

St-Hubert, Quebec

J3Y 6T1 Canada

Phone: (450) 656-2759

Solen Electronique



  • 2023-08-25 03:26:23 PM

    Ian Southall wrote:

    As an international subscriber to Stereophile, I always enjoyed your bimonthly column. I am pleased that you have found a home with Tracking Angle as an outlet for your thoughts on music and hi-fi.

    The series of articles fleshing out your reading list for lovers of recordings is a nice idea - I have bought the first six books and have read 4 of them already. For a British person like myself, growing up in the Fifties and Sixties, one felt back then that the American popular music, blues and jazz etc. we heard at home on our (originally valve) wirelesses was rather exotic. Great to read some of the history from an American perspective. Also sad to read how the quality end of U.S. radio has suffered - the B.B.C. is, for the moment, still doing a decent job in the U.K.

    I also enjoyed this latest article. I had not twigged that this woven carbon composite meta material was being used by a number of loudspeaker manufacturers. There are always claims that new ‘speaker materials are THE big breakthrough and one gets to be sceptical. However, these new ideas do actually seem to have substance. Anyone for a tweeter with carbon meta material cone and a KEF meta material labyrinth absorber to deal with the rear radiation?

    • 2023-08-25 08:37:30 PM

      John Marks wrote:

      Dear Ian, Thanks for the kind words. I do urge you to try to pick up a used copy of "We Interrupt This Broadcast." I think that the cultural differences between US for-profit Classical FM radio and the BBC will not stop you from laughing out loud. The author obviously knows a lot about US classical radio! I have long been a fan of carbon-fiber drivers; I have built a couple or prototypes using the MISCO emulation of the Audax 4-inch/100mm CF woofer. But the Thin Ply stuff is a game changer. Woofer diaphragms, well under half a mm thick. SBA's Beryllium dome tweeter costs 50% more than does the TeXtreme version, but the Beryllium one is only three HUNDREDTHS of a gram lighter. As far as I know, KEF utilizes nano acoustical absorption, but as far as I know, the big patent owner in that field is SSI New Materials (Zhenjiang) Co., Ltd. They claim their nano absorber technology is found in a gazillion cellphones worldwide. I never followed up to request a product sample, but a couple of years ago they were trying to raise their profile in the home and portable audio worlds. Thanks for the idea, and I will make sure to pass it on to SB Acoustics. all my best, john

  • 2023-08-25 04:29:17 PM

    JACK L wrote:


    "Telarc’s Soundstream digital Frederick Fennell wind-band program of Holst, Handel, and Bach, with the Cleveland Winds. The LP version was from 1978" qtd J Marks

    I got the same Telarc LP come with its special thick cardboard sleeve folder holding the record - claimed to avoid up to 10,000V static discharge if using conventional skin-tight plastic sleeve. Luckily, I picked the LP up so unexpectedly from my neighborhood thrift store for a buck or so some years ago !!! It rocks & rolls when playing thru my home-brew all-triode phonostage+5W/5W SET power amp+ 3 active woofers !!!

    JACK L

    I play it often thru my home-brew all-triode phonostage & 5W+5W SET power amp +

    • 2023-08-25 04:45:57 PM

      John Marks wrote:

      Thanks for reading and thanks for writing. Not to sound snide, and I have a lot of respect for Holst, but... Fennell works miracles of pacing and in managing expectations in that famous first track. IMHO. Because if you look at the sheet music, it appears to be just a lot of passing around among the, brass sections a very limited quantity of thematic material. In lesser hands I can imagine the listeners sobbing "Enough already, please stop!" You know, the "Da daaa | da daa. Da da da da, daa. Da daa... ." But listening to that track as Fennel extruded it (or, was he "extracting sunbeams from cucumbers"?), more than once I have heard people applaud, or state they felt like applauding. all my best, john

      • 2023-08-26 03:49:01 PM

        JACK L wrote:


        "Fennell works miracles of pacing and in managing expectations in that famous first track. IMHO. " qtd J Marks

        Yes, but I like much more the 3rd track on side A of the LP: Holst : #3 March. Yet the best tracks I like most of this LP is Handel's The Royal Fire Works music: track 4 & 5 on side B. So brilliant & so powerful performed by Fennell's Winds organized by Fennel like working out a miracle !!! I collected quite a few LPs of Handel's Royal Fireworks Music of pure analogue recordings. Nothing can come close to the Soundstream digital master done 4 decades ago - so powerful so real. This Soundstream mastered LP beats the sound of many of my 40+ digitally mastered LPs made more recently !! Wow.

        JACK L

        • 2023-08-27 12:41:56 PM

          John Marks wrote:

          The "Genius Hack" (which also made inevitable the Achilles' Heel) of the Sony/Phillips S/PDIF system was that it was cleverly designed to use the pre-existing installed base of 1970s Japanese state-of-the-art color TV broadcast recording and playback hardware--Seriously! That how the 44.1kHz sampling rate came about. The only reason it had to be 44.1 rather than the more intuitive 50kHz was that 44.1k can be divided both by 50 and by 60. Given that the scanning rate of television is clocked by the frequency of the wall current (duuh, follow the bread crumbs to S/PDIF's Achilles' Heel of No Separate Word Clock--the timing has to be reconstructed from the Zero Crossings of the audio waveforms!), Sony and Phillips made their system compatible with the installed base of PAL and NTSC video equipment. Early S/PDIF encoded the music as "Black and White Television 'Snow.'" The physical storage medium of early S/PDIF was Sony's 3/4-inch professional U-Matic Video Cassette. Stockham Soundstream was a much less kludgy, far less compromised system. But, IIRC you had to buy about $50,000 in customized computer equipment. Sony won the day because assuming a broadcaster already had racks of Sony video equipment, they could get into the Digital Audio Recording game for about $2,000. BTW, NPR TV Station WGBH Channnnel 44 Boston used to broadcast (after regular TV hours) TV video signals of Black and White Television 'Snow' that, when demodulated by the right PCM F-1 equipment, was CD-Quality audio of Boston Symphony concerts! john

  • 2023-08-26 07:30:12 PM

    JuzDisGuy wrote:

    Great review!

    • 2023-08-26 08:14:52 PM

      John Marks wrote:

      Thanks. It's about the word count/length of two of my Stereophile columns, put together. The speakers and the technology deserve it. Game changers. john

  • 2023-09-03 06:26:00 AM

    tim davis wrote:

    As a DIY hobbyist I was elated to find (finally) some love being given by the press to the TexTreme carbon fiber speaker cone/dome material in this in-depth review of SB Acoustic's x Solen: Sasandu Tx Loudspeaker. Last year I my own self managed (by the seat of my pants barely) to assemble an end-game 2 way build which employed Eminence's own TexTreme diaphragm CD tweeter the N314X-8. I've been nothing but elated ever since as I make my way through a lifetime's worth of accumulated music library played back on what is easily the finest speakers I'll ever be able to afford & the TexTreme element is a major part of that win. After perusing the amazingly microscopic article regarding the Sasandu Tx, I eagerly scrolled down to this very comments section chomping at the bit to finally get interact with others on the subject of TexTreme material only to discover to my horror that this comment section is reserved for thoughts on John Mark's excellent series of book reviews. Why this is the case I have no idea. Undaunted, I'll still post this entry hoping to somehow reach the on-topic discussion subject I had thought would be here. In parting for now, I'll voice my disappointment with (as a great fictional holder of doctorate frequently observed) "Oh, the pain, the pain...".