ENIGMAcoustics Sopranino electrostatic supertweeter Art Dudley November 2016

Art Dudley wrote about the Sopranino in November 2016, Vol.39 No.11):

In audio as elsewhere, there's nothing new under the sun (footnote 1). Thus, in their zeal to give consumers an ever-better facsimile of every note on their records, some audio designers turn their attention to old technologies. The California firm EnigmAcoustics, for example, has found a new use for something as old as the Earth itself: the electret, typified by such abundantly common minerals as quartz. And while EnigmAcoustics make their electrets out of exotic fluoropolymers rather than quartz, they have the same functional characteristic: electrets have an electric charge, which lasts virtually forever (footnote 2).

Fans of the electrostatic loudspeaker will perk up at that—still musing, as they surely do, over the engineering challenges overcome by the genre's greatest-ever designer, the late Peter J. Walker. The trickiest puzzle piece in Walker's development of the groundbreaking Quad ESL, nicknamed the ESL-57, was to devise a constant-charge diaphragm that could thus vibrate in reaction to the application, to the stators that straddle it, of a split-phase version of the music signal. But now—and here's where modern technology re-enters the story and is redeemed, Parsifal-like—EnigmAcoustics has succeeded in using a flexible electret, as thin as a monophonic LP groove is wide (25µm), as a diaphragm for a commercial electrostatic loudspeaker.

The product in question is the Sopranino (footnote 3), an accessory supertweeter reviewed by John Atkinson in the May 2014 Stereophile. For that review, JA paired the Sopranino with the Joseph Audio Perspective loudspeaker—a 36"-tall, two-way, three-driver floorstander ($12,999/pair)—and also with his vintage pair of Rogers LS3/5a minimonitors. With the latter in particular, JA enjoyed the tonal and, especially, spatial enhancements wrought by the EnigmAcoustics supertweeters, declaring that the Sopraninos "made a subtle but genuine improvement in the sound of my system."

Yet a question remained: How would the Sopranino fare with the Quad ESL itself? It seemed reasonable to hope the pairing would be heaven-made: After all, the relatively large size of the ESL's tweeter panel—26" high by 8" wide—creates what even the Quad faithful describe as an undesirable degree of treble "beaming," which in turn limits the size of the listening area from which a pair of the speakers can be heard at their best and keeps their overall treble extension notably modest. The points in the Sopranino's favor are many: at 4.75" by 3.5", the Sopranino's diaphragm is far smaller than the treble diaphragm of the Quad; that and the Sopranino's horn loading would seem to promise better high-frequency dispersion. Moreover, to the extent that any loudspeaker technology has its own characteristic sound, the electrostatic Sopranino might also be expected to blend seamlessly with the Quad.

And, perhaps best of all, the Sopranino's optional stand ($600/pair) appears to have been designed with the ESL in mind. These well-made, sturdy, aluminum stands allow the user to set the supertweeters at any of nine different heights, from 29" to 46" between the floor and the bottom of the tweeter, and one of those heights—32" above the floor—places the Sopranino so that its bottom just clears the top edge of the ESL, when the latter is used with its standard wooden feet. Not only that, but a dovetail notch at the front of the stand's baseplate perfectly accommodates the ESL's central, rear-mounted leg, allowing the user to scoot the Sopranino farther forward than would otherwise be the case. Neat.

A number of months ago, Quad ESL enthusiast Robin Wyatt, of the New Jersey–based distributor and retailer Robyatt Audio, loaned me his demo set of Sopraninos: two supertweeters and two stands, all of which had seen active duty at a few audio shows in the Northeast. Speakers and stands are supplied by EnigmAcoustics in excellent packaging—especially the speakers, which come in a padded wooden box all their own—but one of the tweeters of my review pair wasn't working. I kept the stands, returned the tweeters, and before long, EnigmAcoustics themselves had sent me a fresh pair of Sopraninos. I connected these in parallel with my well-worn Quads, using the jumper cables EnigmAcoustics supplies for that purpose. Of the three rotary-switch-selectable bottom frequencies for the Sopranino's high-pass filters—8, 10, and 12kHz—the 8dB setting gave the most pleasant and believable blending of highs and superhighs, particularly with voices and trumpets. Depending on the recording, I used the –0dB or –3dB setting of the two-position Gain switch, but relied more on –0dB.

After several weeks with the ESL-Sopranino pairing, I came away respecting but not quite loving the EnigmAcoustics' contribution to my system. Were I the sort of listener who places a greater emphasis on stereo imaging, I might feel differently: In my system and room, the Sopraninos made, by far, a greater improvement in spatial performance than any other aspect of playback. I heard the same effect with record after record, but it was seldom more notable than when I listened to the recording of Heinrich Schütz's Musikalische Exequien by Phillippe Herreweghe and La Chapelle Royale (CD, Harmonia Mundi HMC 901261). I focused my attention on the brief tenor solo that opens the piece: With the Sopranino added to the system, my response was similar to when I sit in my optometrist's chair and she switches her phoropter from a poor setting to one that's optimal—everything snapped into aural focus, so much so that the effect seldom failed to coax from me a surprised laugh. The difference was remarkable, the degree of spatial precision added by the supertweeter undeniable.

Especially with pop recordings made with generous use of overdubbing, adding the Sopraninos to the mix also offered a slight enhancement of subtle details of playing and singing. I have finally, after years of neglect preceded by years of overexposure, begun listening once again to the Beatles' Abbey Road (CD, 2009 remastering, EMI 3 82468 2), and I noticed that the addition of the Sopranino supertweeters made it slightly easier to hear John Lennon's piano work in those famous descending chords in the middle eight of "Something" (footnote 4). That said, for whatever reason, having the Sopraninos in the loop with my Quad ESLs, driven by my Croft Phono Integrated integrated amp, also resulted in an equally slight lessening of body, presence, and overall flesh and blood in the sounds of instruments and voices. With the supertweeters, every recording sounded more sharply focused and detailed, but also less corporeally there—and that's an aspect of playback that I'm at pains to maximize, always.

Notwithstanding the glitch in one speaker of my first pair, the Sopranino appears exceptionally well made, and its existence as the only electrostatic loudspeaker of my knowledge that doesn't require a bias supply—something that adds cost, complexity, unreliability, and even danger to any electrostatic panel—makes it all the more praiseworthy. But the Sopranino, while effective, seems aimed at a listener with priorities different from mine. At the end of the day, my assessment of the EnigmAcoustics supertweeter is precisely the same as JA's: "An audition will be mandatory prior to purchase."—Art Dudley

Footnote 1: Stuck for an intro, I got out my credit card and leased this opening sentence from the good folks at www.audioreviewcliches.com. It was only slightly more expensive than "'My name's Art and I'm an audiophile.' 'Hi, Art.'"

Footnote 2: Defined, for our purposes, as 100 years or so.

Footnote 3: The EnigmAcoustics Sopranino costs $3690/pair, excluding stands. EnigmAcoustics, 11 Chrysler, Irvine, CA 92618. Tel: (949) 340-7590. Web: www.enigmacoustics.com.

Footnote 4: It's a tantalizing and somewhat frustrating hint: As can be heard on such bootlegs as Unsurpassed Masters Vol.5 (1969) (CD, Yellow Dog YD 005), Lennon's piano work in the rest of the song, which was omitted from the final mix—along with the coda that he seems to have kicked off—is both passionate and technically quite good.

11 Chrysler
Irvine, CA 92618
(949) 340-7590

remlab's picture

..around an inch long. The distance of the super tweeter's center looks to be several inches from the main tweeter's center. Relatively speaking, it would be like placing a subwoofer a hundred feet from the mains(Kind of). It seems like the potential for destructive interference due to timing variations would be pretty bad. For this reason, off axis measurements/w main speaker would have been interesting.
Another thing, regarding show conditions, is that if you are not sitting perfectly on axis with these supertweeters(90% of show listeners usually aren't), what you are hearing from it is probably just your imagination, or destructive interference at the crossover point.

dalethorn's picture

"There was a sense of loss every time I disconnected the supertweeters, the imaging losing some of that addictive palpability."

That's the key I think - that direct comparisons don't reflect the full difference. I've learned that inserting a component that improves the sound in this subtle way doesn't make quite the impression that removing said component does, once the listener has accomodated to it.

hnipen's picture

John, I do have asthma too, suddenly I realize how this may bee a good thing, thx for info John :D

Catch22's picture

If I start smoking, can I get asthma too?

remlab's picture

So there is no way for me to stay in the sweet spot long enough to hear any benefits anyway..

hnipen's picture

@Catch22, Asthma is allergy related and has to do with a narrowing of the airways, due to these allergic reactions, smoking can reduce your lung functions and make other problems with your airways, but it can't give you asthma.... as far as I know (I'm not a doctor, though)

When I was younger I also had asthma when exercising, but as far as I know, it's always allergy related, but potentially being more disclosed when you exercise, but still it's allergy that's always the core reason, I believe

remlab's picture

..catch22 and I were just trying to be funny(out of insane jealousy, of course).

hnipen's picture

Geir Tømmervik, master chief of Oslo Hi-Fi center has a supertweeter that goes to 200KHz for his Audio Physic Medea (well, the medea seemingly has been replaced with Kef Muon) .... He wholeheartedly claims that everything gets better when he employs the supertweeters, even the bass!

Geir is a person that always proves what he says, so I don't believe this to be rubbish.....

remlab's picture

Would sound even better!

Rick Tomaszewicz's picture

I wonder how much of such improvements is the result of things like the McGurk Effect, wherein what you see affects what you hear. Could a double blind test help in determining actual improvements?

See the following for an explanation.


John Atkinson's picture
Rick Tomaszewicz wrote:
I wonder how much of such improvements is the result of things like the McGurk Effect, wherein what you see affects what you hear.

Always a possibility with even the most experienced listeners. But then how would you explain that I detected that one of the supertweeters had stopped working properly, something I confirmed by measurement?

Rick Tomaszewicz wrote:
Could a double blind test help in determining actual improvements?

As I wrote in 1997, following my experience as a listener in many double-blind tests organized by others - see www.stereophile.com/asweseeit/407awsi/index.html - "double-blind comparative listening tests [are] the last refuge of the agenda-driven scoundrel."

John Atkinson
Editor, Stereophile

Rick Tomaszewicz's picture

as Remlab suggests, your recognition of the failed super tweeter was related to the sudden absence of additive or subtractive effects within the audible range of that channel.

As an avid reader of Stereophile and its sister publications, I'm familiar with the ongoing debate concerning double blind testing. Both points of view have been eloquently argued. Mikey F. has also commented on the need for educating one's ears prior to making judgements. I note Philips provides an online tutorial to help in this regard.


I acknowledge that you and your writers likely have among the best educated ears around. However, I do not understand why audiophiles should be exempt from the same rigour most other technical fields subject claims to; namely, double blind testing. It's for this reason I admire Mikey's blind listening polls to compare gear. (I don't think one has to have an agenda or be a scoundrel in order to seek such objectivity.)

I've suggested before that an interesting annual feature could be for you and your writers to blind listen to gear in differing price ranges, and rank all in absolute terms and then rank based on cost ratio. For the 99.9% of us, that last category would be most valued. Because, in the end, it should be about the music. And the closer we can get to the artist at the least cost, the better. (The wealthy can buy gear to impress friends, but perhaps some of them would value exposing "emperors without clothes".)

Rick Tomaszewicz's picture

I forgot to express thanks for the restraint of your conditional commendation. Such measured and sober assessment is rare among reviewers of glamorous high end gear.

Also, from a marketing POV, was it wise for the creator of such expensive gear, at the edge of perceptive benefit, to include the word "Enigma" in their name?

dalethorn's picture

I explored the Philips Golden Ears test/challenge, and found that while it's interesting, the cancellation** factors between their proposed 'colorations' and colorations of the devices you're listening with can lead to dubious conclusions. While I believe that the subtractive effect of switching from the 'better' component to the lesser component, and hearing the loss of resolution that incurs usually reveals an important difference, it isn't always that simple. Sometimes you just have to spend a lot of time trying different things.

**i.e., the source has an emphasis at 'x' khz, while the speaker has an equivalent recess at 'x' khz.

remlab's picture

..just be from destructive and constructive interference at the relatively low crossover point? If it is simply meant to extend the response of a loudspeaker, wouldn't it make more sense for it to to start at 20khz if the mains tweeter is more than capable of getting there itself? I'll bet that you would have a much more difficult time guessing wether it was in or out of the system in that case.

JRT's picture

If the loudspeaker performance is so poor that this bandaid fix may improve that performance, I would suggest getting better loudspeakers.

The MSRP of these supertweeters is $3690.

For $1499 from KEF-Direct, you can get a pair of KEF LS-50 satellite stand mount monitors.

The little KEFs need a subwoofer system for full range response. Some might argue that a subwoofer system is a bandaid fix, but I would counter that using sepatately located sources below the Schroeder frequency can provide a better solution to smoothing Eigentones in the modal response of the listening space. That woud be a better designed solution, not a bandaid fix.