Acelec Model One loudspeaker

The Acelec Model One speakers I'm auditioning ($6495/pair) are not princesses in pink, or frog green, or made of some chemically distilled polypudding. Nor are they conventional-beyond-reason MDF boxes covered with stick-on vinyl pretending to be wood. The Model Ones are squat, small, serious-looking, two-way standmounts. They are 11.2" tall, 7.7" wide, 11.5" deep, and 37.5lb heavy.

My review samples look serious because they are constructed of black, 15mm-thick, internally damped "bituminized aluminum" panels, which, besides being rigid, look full-metal stealth and recording-studio professional. Cees Ruijtenberg of Sonnet Digital Audio—Acelec is a Sonnet Digital Audio brand and Cees is Acelec's chief designer—wrote to me in an email that this well-damped stiffness "avoids ringing and time-smearing with regard to fast, powerful transients." If you don't want black, you can also get silver, and fancier colors available on request.

Ruijtenberg continued: "We believe that our aluminum construction differs from what we see from other manufacturers. Typically, their panels are tightly connected to each other, or their cabinet is milled from a single piece of aluminum. These tight connections ... make their enclosures resonate like a bell. In our design, the panels are connected with a kind of rubber glue so that there is no unity between the individual panels."

The Model One's Mundorf AMT tweeter and 5.9" sliced-paper–cone Scan-Speak bass/mid driver, which has a neodymium magnet, are crossed over at 1.8kHz in what Cees calls a "dual slope design": "The crossover frequency is initiated with a first-order [filter], 6dB/octave, but further away on either side of both slopes, a second-order [filter]—12dB/octave—kicks in. This allows for a milder phase behavior at the crossover frequency."

I asked for placement tips. "Placement within a normal living environment was also a design goal so that performance would not be hampered, for example, by close proximity to room boundaries (e.g., walls and corners)," Ruijtenberg wrote. "Furthermore, the design had to behave efficiently and act as a simple load for a wide range of amplifiers, encompassing delicate tubes as well as powerful solid state types." Reading this caused me to pause and applaud. I mean, is it really that difficult or a compromise to make a speaker easy to position and easy to drive?

More than any speaker I've used before them, the Acelec Model Ones looked and felt like they were made especially for my heavy, 24" Sound Anchor Reference stands. Their gray-black surfaces matched tone- and color-wise, and the One's 12" × 8" footprint exactly matched the Sound Anchor's 12" × 8" platform. Their textures and densities matched well too. Speaker and stand seemed to join visually and physically.

I mated the Model One speakers to my stands three different ways: first, with only gravity and friction holding the Acelec's textured bottoms to the Sound Anchor's textured tops. They sounded crisp and lively like that. Next, with pea-sized balls of Blu Tack between the Ones and the stands, I discovered a silent atmospheric transparency that I found appealing. Finally, with the Model Ones sitting on the supplied 1"-high aluminum cones, their boxes seemed to disappear more than they did sitting loose or puttied to the Sound Anchors.

Acelec's screw-on cones placed the tweeter's centers about 33" from the floor, approximately 1" below the center of my ears in my listening position. I did all the listening described in this review with four cones under each speaker.

Consistent with the design brief, Acelec's Model Ones were not fussy about placement. I moved them around in a deliberate attempt to find where they didn't work. I ended up with about 30" from their front faces to the wall behind them, 74" apart, and 96" from my ears. This was the position in which they had the clearest, strongest voice.

The Acelec Model Ones are made in the Netherlands, imported and distributed in the US by Audio Art Cable. Rob Fritz, proprietor of Audio Art Cable, suggested I try his own AAC Statement e SC speaker cables ($1220/4' pair). I told him I would, but only if he felt certain it would give me the best chance of hearing everything the Model Ones had to offer.

I also tried the Acelecs with my reference Cardas Clear Beyond cables ($9220/2m pair). To my ears, the Cardas let the Model Ones sound more corporeal and more fully detailed than the Audio Art cables did. I also tried the silver-wire Kangai-level cables from Ikigai Audio ($6500/2m pair), which I thought rocked the One's dynamics and purity levels up a full notch. In the end, I used the Audio Art wires because they were a good match. They played all genres of music in an engaging fashion, made exceptionally detailed bass, and did not appear to compromise the Acelec's uncanny transparency.

During my first day of break-in listening, the most interesting thing I noticed was how much more intelligible singer/guitarist Bo Carter's lyrics were—how his words were better formed and enunciated and how much more obvious and erotic his double entendre seemed. Playing the Yazoo Records' Bo Carter anthology Twist It Babe (1931–1940) (16/44.1 FLAC, Yazoo/Tidal), the Model Ones presented the artist's voice singing campy songs with a starker, more microscopically rendered clarity than the Klipsch RP-600M IIs that preceded them in my loudspeaker auditioning queue. With the budget-level Klipsches, Bo's voice seemed to emerge from an attractive but slightly hazy neon-lit environ. With the Acelecs, the sound was stark, dark, and no-glass clear.

No matter how hard audio designers try, every audio product seems to end up sounding like what it's made of. Plywood boxes sound like plywood boxes, with ring tones of varying duration, depending on the size of their cabinet. The ubiquitous MDF cabinet contributes a dead-thunk box-speaker sound.

Today, in order to minimize such cabinet-caused colorations, a small cadre of widely respected, top-level speaker manufacturers make cabinets out of aluminum. The engineering benefits of aluminum are obvious and seductive, specifically its high stiffness-to-weight ratio. But does aluminum really disappear as well as its proponents claim?

At audio shows and people's houses, I've auditioned a variety of YG Acoustics speakers, which use milled aluminum panels, and Magico speakers, which use extruded aluminum panels and other forms, and I thought both speaker brands shared a distinct and appealing form of clarity not found in speakers using more sundry cabinet materials. I can also report what I experienced reviewing two other brands of loudspeakers using aluminum cabinets: Genelec's G Three, which uses a biomorphically shaped cast aluminum cabinet, and Stenheim's floorstanding Alumine Three, which uses CNC-machined aluminum panels that vary in thickness from 0.5" to 1.0".

The Genelec G Threes demonstrate that aluminum speaker cabinets can come close to disappearing. When I compare them (by memory) to the thicker, taller aluminum cabinets of Stenheim's Alumine Threes and now, directly, to Acelec's Model Ones, I can hear the thin-walled G Threes as having a faint, high-pitched metallic taint lacing their grainless, reference-level transparency. If memory serves me, the ringtones of Stenheim's tall cabinets were nearly impossible to find; if they were there, they merged inconspicuously with whatever low-frequency sounds the ports and bass drivers were emitting.

The Acelec Model One's aluminum panels came even closer to complete silence. Nevertheless, when I tried to find it, I noticed what I presumed was the specter of its aluminum enclosure: a slight, eerie density hovering near the musical program. Its level was exceedingly low, so I did not regard it as a coloration. I thought the fact that I could notice it at all was proof of how extraordinarily clear, microresolved, and uncolored the Acelec Model Ones are.

After transparency, the One's most conspicuous trait was its unflappable ability to deliver perfectly sorted, minutely organized, naturally displayed recorded data. In this performance category, it equaled TAD's $32,250/pair CE1TX monitors, which I thought sorted and displayed recordings more completely and effectively than any speaker I had previously encountered.

Acelec/Sonnet Digital Audio BV
Daviottenweg 9-11
5222 BH's-Hertogenbosch
The Netherlands

tenorman's picture


georgehifi's picture

Nice review, but!
$6.5K usd for an 11" two way!! You guys are tripping? drunk? or bombed? Or is everyone in the US a multi millionaire?

Cheers George

JRT's picture

A loudspeaker with MSRP approximately 5x multiple of the low volume retail pricing of the BOM components in total usually represents fair pricing. This loudspeaker is priced well below that, just considering woofer and tweeter, not including the crossover and other misc components, and without any consideration of the nontrivial enclosure. And it does seem to perform well.

The drivers are not cheap. Madisound's mailorder retail pricing for ScanSpeak Illuminator 15WU/4741T-00 is $381/each, and for Mundorf AMT21CM2.1-C (air motion tweeter) is $534/each. While I wouldn't know if this loudspeaker uses those exact off the shelf drivers or some OEM variants better optimized for the specific application, these drivers are sufficiently representative for use in coarse estimates.

$381 + $534 = $915 for the drivers in one of these loudspeakers, x2 = $1830/pair, x5 = $10980, nearly $11k. The MSRP is only $6.5k/pair.

Whether or not one might consider it to be well engineered is another very different conversation that must include the opportunity costs of what else could be achieved within the same budget.

georgehifi's picture

From Mundorf and ScanSpeak, in lots of probably 100 or even more, and the costs would be around 1/8th of those retail sellers prices, $228 for drivers for the stereo pair, plus box cost etc.

Cheers George

JRT's picture

Of course the manufacturer is not buying drivers at retail prices. That coarse approximation also does not include all of the other costs.

It is just a useful heuristic coarse approximation which uses a 5x BOM to MSRP with low volume retail pricing on the BOM components (which would include not just the drivers, but also the crossover, enclosure, lining and stuffing, wire, binding posts, screws, etc., which I didn't bother to include all of that because the prices of drivers alone clearly indicate a low MSRP relative to costs). It is just a sanity check on pricing of loudspeakers of moderate production volume.

Also... That 5x multiple does not apply to the very low volume high end statement products trotted around to the audio shows for marketing purposes, where high pricing adds to the wow, and the intent is to attact customers to other less expensive product. Those can exceed 20x BOM to MSRP.

My source on that was Siegfried Linkwitz, more than 2 decades ago in some discussions on the old Mad-board, either while or shortly after his involvement with Audio Artistry. SL's Audio Artistry Beethoven design was Stereophile's loudspeaker of the year in 1997. I have included a link to the review below. His heuristic coarse approximation still seems to hold up well enough to remain useful.

Dennis Murphy's picture

This appears to me a very well engineered speaker with expensive drivers and what is probably an extremely expensive cabinet. However, the woofer is not from the Scan Speak Illuminator series. It's from the older and less expensive Revelator models--the 15W/8530K-00 It retails for $221. To the very best of my knowledge, there are no neo magnets in any of the Revelator woofers.

Long-time listener's picture

One other thing I don't quite understand is why manufacturers now want to make all their bookshelf speakers SO small, when a slightly larger cabinet and woofer could bring better bass extension. Maybe they assume everyone will use a subwoofer if they want bass extension. Not me. One other example is Revel, who downsized their famous old M20, again limiting bass extension. Anyway, I just don't want to have to pay $6,500 and then have to get a subwoofer on top of that.

Archimago's picture

Not everyone. But apparently all Stereophile readers are.

Indeed. A wee bit pricy... At least the measurements look alright.

teched58's picture

The funniest thing re the closing line of the review: "Acelec's reasonably priced Model One could be the speaker you've been searching for..." isn't just that it was probably added in during the edit.

It's the no one who makes their living at Stereophile could "afford" this speaker, if we're talking about the money they make from this site. (Not talking about rich relatives or remuneration from other careers, e.g., the eminent, retired professor in Manhattan who is a contributor.)

So TO WHOM IS THIS tiny little but very expensive speaker AFFORDABLE?

It's also very funny that Stereophile thinks that the little editing tic of putting "affordable" into every review makes it so.

In fairness to the current regime, I think it was Mikey who started this practice years ago. Perhaps to convince himself that he could "afford" the $100,000+ turntable for which he took out a bank loan.

JRT's picture

"Not even the people at Stereophile could afford this" - teched58

If the reviewer buys the review sample, after the review, then it is no longer a new version in an unopened box. Rather the condition is that of a demo unit, because of the review.

I would hope that a reviewer could acquire it at a discounted accomodation price in the vicinity of dealer cost or maybe further down near the distributor's/importer's cost, if the condition is simply broken-in from use in the review, but otherwise as-new in all functions and cosmetics, with original box, packaging materials, paperwork, full warranty, etc. If it has suffered some minor inadvertent cosmetic damage, then it should be further discounted accordingly.

And whomever is paying the freight on the review sample saves the cost of the return shipping, an argument which the reviewer might use in further improving the discounted transaction price.

And if delivered from the distributor or manufacturer from out of state inventory, there might not be any sales tax in the transaction price. Herb lives in Brooklyn, NY, which has a sales tax rate of 8.88%.

Anton's picture

If a seller/whomever offers in home demonstration of gear, then shouldn't I get 'used pricing' on it after trying it in my home? And, if I slightly damage it, I would insist on an even greater discount.

Count me in!

I'm gonna use this idea. After I take a car for a test drive, it is no longer new, and I should get used car pricing.

Kal Rubinson's picture

Worked for me. I did a test drive in a car, came back 2 weeks later for another and negotiated a lower price based on its use/mileage.

Anton's picture

I could 'save up' and get one. Maybe if they had said "reasonable accessible?"

I'd actually love to compare this to a vintage Infinity Intermezzo 2.6....aluminum enclosure, very easy to drive, not overtly large...

Class A sound, in it's day.

Even setting this new speaker next to a Celestion SL600Si (even though it is 30+ years on) might be fun.

Speakers this size are perfect for shoot outs. Our club has done some and they have been extremely eye opening.

Ortofan's picture

... speakers of essentially the same size or form-factor, how about a comparison with other speakers that are similarly priced?

What might be the outcome of a shoot-out between the Acelec Model One and the KEF R11 Meta, the Klipsch Cornwall IV and the Wharfedale Dovedale?

bhkat's picture

It would be interesting to see this manufacturer make a floor standing speaker that sells for around double. This speaker's FR measures better than the $100,000 speaker reviewed recently.

Long-time listener's picture

I appreciate Herb Reichert's reviews, as I appreciate all Stereophile reviews. Except when they say things that have no meaning: "a slight, eerie density hovering near the musical program..." NEAR the musical program? Where would that be? And "density" ... of what? If there's a problem with this speaker, language like this isn't communicating to me what it is.

johnnythunder1's picture

It's good writing. I know exactly what he means and I don't want to read a dumbed down version of HR's descriptive abilities. I think he perfectly described a VERY subtle type of coloration based on the construction and materials of that speaker. And "hovering near the musical program" simply means that this subtle coloration is affecting the music coming out of the speaker.
Or at least that's what it meant to me.

johnnythunder1's picture

Like a Monet painting as opposed to a detailed photograph. Herb doesn't write "white papers" thankfully. He's trying to express a "feeling."

Herb Reichert's picture

infuse the recorded program like cream in your coffee.

In my reviews, I do my best to describe what I notice in terms mastering engineers would understand.

When I say “faint” and “near” I mean the Acelec's box coloration is barely noticeable, and that if you listen carefully and you do happen to notice it, it is sitting off separate from the sounds of the recording. From a listening standpoint this is ideal.

I hope that clarifies "near."

As for “density” I always mean that as a measure of the amount of information being transmitted by a system combined with the apparent intensity of sound energy coming out of the speakers.

If you ever experience 30ips tape recordings played through big Genelec Studio Monitors you’ll know exactly what I mean.

I hope that helps because I want to be as specific and choose my words as carefully as I can.


jimtavegia's picture

I have an album, not the only one, where there were (many) 12 engineers involved with just the recording of the album's tracks. They are all over the place sonically. I don't understand the reason an artist would do such a thing and every track sound different with varying levels of compression, EQ, and limiting. Not a good album to use as a speaker test, sadly. I am a fan of this artist, but may be most of his fans could care less about recorded quality?

I think of the sonic variances of Gould's 1955 and 1981 Bach pieces that had tremendous recording differences and pianos. I have both as many do and find the '55 recording thin and not very realistic. I think both were done to tape.

Do you define as your standard the 30 ips recordings as heard through the Genelec's? That certainly would give you a one-up on those of us who have not heard that.

I am going out this week to start the audition process for some new bookshelf speakers and my first one is going to be the small Magico's. There is a dealer not too far and I will take some music I know and begin the process of hearing what is near the best in that category. It would take a lot to "wow me" to drop this kind of money on speakers, but I am going to start there and see where it takes me.

As for the recordings, since we are not there in the room where the recording is made we have no idea if what the engineer did or the mic choices he made captured accurately what is going on in that room. I am sure something is always lost. Just a part of the process where choice determine the outcome.

I appreciate your thoughts on this. It is complicated is an understatement.

Herb Reichert's picture

I've only heard 30ips a few times and then only briefly.

I was using the 30ips/Big Genelec comment as an illustration of what information density and sonic intensity sound like together.


Glotz's picture

AXPONA had a very nice demo with Garth Leerer and ticked all of the boxes for a small mini, for me. Stunning and satisfying.

I would love to have Herb review them in context of the other monitor speakers he's been reviewing of late.

RH's picture


"As for “density” I always mean that as a measure of the amount of information being transmitted by a system combined with the apparent intensity of sound energy coming out of the speakers. "


I had interpreted your general use of the term "density" differently.

I thought you used the term the way I do: to describe when a speaker produces more of the sensation of a corporeal sound, especially in the sense that it's sonic images were "solid" and "dense," closer to the sensation you could reach out and touch the object, rather than having a ghostly, see-through, "wave your hands through it" quality.

The Devore O series speakers, for instance, for me produce more density, more "flesh and blood" presence, than I hear from your average skinny floor standing speakers, which transmit plenty of "sonic information" but produce a more spectral-like soundscape.

Herb Reichert's picture

"I thought you used the term the way I do: to describe when a speaker produces more of the sensation of a corporeal sound, especially in the sense that it's sonic images were "solid" and "dense," closer to the sensation you could reach out and touch the object, rather than having a ghostly, see-through, "wave your hands through it" quality."

But lately, I am noticing that the illusion of corporality can also display a force or intensity factor.

Corporality is surely the result of more low-level information getting through without being sucked

out during DA conversion or in a complex crossover.

Or maybe I've played "White Rabbit" too many times?


RH's picture

I hoped I hadn't been misreading you all this time! :-)

Btw, I wonder if your experience agrees with the following...

There seem to be different aspects of "density" and "body" portrayed in different systems.

For me, a sense of sonic density and palpability is a characteristics I'm always seeking. I ultimately prefer tube amps, and have been using CJ Premier 12 tube monos for many years. But I often grab different SS amps to try. My observations are that both the tube amps and the solid state amps provide density, but in a different way.

The solid state amp produces a sense of solidity and impact with leading edges of sound, and especially hard edged sounds. So for instance a hard edged "industrial" synth bass line in an old Depeche Mode track will appear as a very tightly controlled, narrowly delineated, solid column in between the speakers, with leading-edge force. I liken the solid state presentation to the type of solidity one hears when striking a solid object with a hammer. Very convincing in that sense.

Whereas the tube amp will slightly soften the edges and fill out the sound, but "round out" the sense of body, vs the "skinnier, more malnourished" version of the solid state presentation. Trading some hard edged convincingness and percussive power, for a more convincing, expanded, richer sense of body. More like punching a big heavy bag, vs a hammer hitting a narrower solid object.

Does that "resonate" with you? :-)


I own Joseph Audio Perspective 2 graphene speakers and have owned Harbeth Super HL5+ speakers (the Harbeth line being one of my favorites). I concur with your Joseph Pulsar review, where you described the Harbeth as having more corporeality, meat on the bones, and textural presence, vs the more detailed, razor imaging and timbral nuance of the Joseph speakers.

I was attracted to Devore O series speakers for similar reasons. But I was still besotted with the incredible grain-free timbral beauty of the Joseph speakers (and their juicy, fun bass response).

FWIW: I have found that the CJ tube amps flesh out the sound of the Joseph speakers somewhat, and I've discovered that adding a curved diffusor behind and between the speakers has a fairly startling effect of bringing focus and density to the sonic images! So I'm enjoying the incredible detail and smoothness of the JA speakers, their enormous soundstage and precise imaging, but the instruments that occur around the speakers have a very convincing texture, and reach-out-and-touch it palpability. So far, close to the best of both worlds! (Though the Harbeth still pull ahead in the sheer human quality of vocals).


RH's picture

One reply per customer, I guess :-)

Ortofan's picture

So, how does HR prefer his "coffee" - with or without "cream"?

Would you choose this Acelec speaker over the Harbeth Monitor 30.2 XD?

Long-time listener's picture

I appreciate that.

I realize it takes a few more words, but "a barely noticeable box coloration, which in any case remains separate from the program material" would have been far more understandable to me than what you originally wrote.

But again, thanks for your reviews and for Stereophile as a whole, which I've been reading for decades.

Long-time listener's picture

Are they the primary target audience for this magazine?

jimtavegia's picture

This must be one of the least resonant speaker cabinets that JA1 has ever measured. I would guess that this IS a desirable thing in speaker cabinet design?

It would be the opposite of most string instruments where there must be wide range of resonances inside a violin, viola, or cello where there are posts that can me moved around to obtain the desired sound the instrument owner wants and they do move from playing, vibration, and humidity over time.

As for the price, I am over the higher prices as I get it as the builder does get to set that based on his costs and work. It is less than the bookshelf Magico model and that would be a good comparison in a side by side test.

It is clear that this is much different than the engineering of the newest versions of the BBC monitors of today. This is where the potential customers will have to audition and decide for themselves. Most of those customer can afford either one. The improved clarity of the vocals is not to be missed or ignored.

A good review and testing.

georgehifi's picture

"This must be one of the least resonant speaker cabinets that JA1 has ever measured."

So is a "Besser" building block
And both around the same size.

Cheers George

jimtavegia's picture

You could have separate chambers for the tweeter and the woofer.

Glotz's picture

Been a good comparison in the resonance discussion / comparison sections of the review?

I think transparency is simultaneously obvious and obscure when speakers are compared, but perhaps the lack of a cabinet could have drawn a useful comparison.

But perhaps not, in the realm of planar vs dynamic definitions of transparency to source. I do believe they are a moving target.

jgossman's picture

At some point we have to just roll our eyes. I have been sort of out of it since getting married and having a kid, but I don't want to hear a review of these against another 6k tiny speaker. I want to hear a review (honest to goodness review) of this against a Focal Aria 906, a Kanta at a still pricy for most people 3k+, and then a 6k floorstanding. The truth is, as I read the review all I could think is pull back the treble, then is there still all that "detail". I've heard a pair of Spendor BC-1's and I own a pair of vintage BW Matrix (before those awful kevlar cones). I know what REAL midrange detail sounds like. I'm guessing we aren't talking about the same thing with these modern tiny little monitors. I'm sure they sound fine. At some point we need to say "Really? I mean, really?".

MBMax's picture

Herb, you made no mention of comparison with the beloved Falcon LS3/5a's. Yes, half the price, but similar form factor and application methinks.

I just purchased a pair of Falcon Gold Badges to replace my beautiful pair of DeVore O/93's that I just couldn't get to work in my small space (HUGE 40-80hz resonance that I could not dial out). My placement options are very limited and the O/93 rear ports fed the nightmare bass hump, even when stuffed.

The Falcons have solved that issue (even on the rare occasion when I turn on my REL sub) and they are glorious. Every glowing word written is true in my estimation and the DeVores will have to find a new home.

That said, I wish I had heard of these before buying the Falcons, though the rear port and the 2x price probably would have killed the idea. Oh, and by the way, my 15W Shindo Montille drives the Falcons just fine.

Just for kicks and grins, how do the two speakers compare?

bilguana's picture

Please review the new ELAC Vela 404s.