Sonoma Acoustics Model One Electrostatic Headphone and Amplifier System Page 3


Sound Quality
The Sonoma Model One Headphone System is neither bright nor dark. There's no bloated nor thin bass. There's no mid-range suckout or screechy peak at 5kHz. Imaging isn't in your face or vaporously unspecific. Dynamics aren't mushy or eye-poppingly hard. It just does everything—well, except for that distorted bass at high levels—very well. The Sonoma Model One is simply, and astonishingly, well's a treat for the ears.

I need to add here, as you can see on the measurements page, apart from the bass distortion at high levels, the bass response of the Model One is tight, impactive, and very well extended. The bass response at responsible listening levels is excellent.

Now it certainly doesn't do some things as well as other headphones. The Audeze LCD series easily bests it in bass response. Though I didn't have it here to compare, I would guess that the Stax SR-009, when well driven by upstream gear, has more nuanced resolve in the treble. And I'd say a piar of Sennheiser HD 600s in a nice rig would best it in mid-range liquidity. (It would best many if not most reference cans there.)

But to my ears, none of them have the tonal balance of the Model One, and none of them do so many thing so well. In the word's of one well experienced SBAF member, "'s a breath of fresh air to put on a headphone and hear something...normal." For me, that statement carried the essence of my experience with these cans: They just sound good. As Sonoma quotes on their web site:

"Frequency response is the single most important aspect of the performance of any audio device. If it is wrong, nothing else matters." — Floyd Toole


On the down side, as previously mentioned, bass level is limited. Also, I find the treble slightly...well, grainy is a bit too course, let's go with hazy. Maybe its all those drivers in the same cup, or maybe it's some digital artifacts from all the DSP wizardry, but the treble resolve seems a little soft and unfocussed. I liken it to the difference between plain and textured glass in front of a painting: The textured glass generally looks better...until you get very close up and begin to see the blurring of fine detail. Image stability is good, but separation and specificity is a bit foggy. Imaging width is good, but is a little shy of having average depth. In those particular characteristics, the Model One doesn't quite rise to reference level.

On the other hand...that balance! While the Model One system isn't great in any one particular area, other than tonal balance where it is great, they are very good in most all. At normal listening levels everything comes together in a marvelously listenable experience. In addition to the tonal balance, dynamics are really good—until you start teetering on the volume limits. This unit has plenty of pop and potent thump at normal listening levels. Normally, I'm too hardened to be drag around by the nose with a piece of gear, but I found myself side-track exploring music for music's sake quite a bit more then usual with the Model One. A very good sign.

Previously I had been quite concerned I'd catch a case of digititis given all the digital whiz-bangery going on inside the Model One but, other than that mild haziness, I heard none. I was impressed over and over again at its easy, natural sound. This experience has me believing that all that work making DSD recording and editing workstations gives this development team all the chops they need to make sweet digital front ends. It also has me believing that DSP correcting headphone amps paired particular headphones may indeed be the way of the future.

An important note here: As I said the Model One is quite sensitive to analog input levels and the user needs to be sure to stay within the operating envelope. Max voltage RMS on the high level input (RCAs) is 2.1Vrms and 850mVrms on the low level (3.5mm jack) input. If you exceed these levels you will run into trouble. I would suggest the best analog source for the Model One is the variable output from a pre-amp or headphone amp. Set the volume control on the Model One to maximum and adjust listening levels from the variable source.

I found using the digital input delivered the better quality listening experience; the haze was a little more noticeable on the analog inputs. I had absolutely no problem whatsoever feeding it any type, bit-rate, word depth file; it performed flawlessly in that regard. Again, the chops this team has in digital audio was readily apparent in the fact that it just worked...every time.

An Astonishing Result
Over the course of this review I came to have more and more admiration for the development effort exhibited. From what I can tell, the HPEL driver within it can be pushed to the ragged edge of its performance envelope. A headphone sized HPEL transducer seems to have just enough volume to be an appropriate choice for headphones. The distortion products from an array of variously sized single-ended emitter cells is so complex that only massive amounts of finite element modeling and state-of-the-art DSP could correct for it. Taking a completely new transducer technology and turning it into a listenable product is a daunting task. Actually making a manufacturable product that sounds excellent in the span of a few years is almost beyond belief.

I want to see a $700 wired version of this thing with batteries and electronics in the headphone, please. Aw heck, since I'm asking, how about with DSP capable of virtual and augmented reality for a grand?

Random Speculation for Entertainment Value
There's a thing called a Phased Array Radar. It is made of dozens or hundreds or even thousands of small radar transmitters arrayed on a flat panel. If they're all in phase the panel will beam straight out...just like those HPEL panels made by ZonarSound mentioned at the top of the article. But with a phased array radar you can control the phase of all the cells independently, which allows you to spread, focus, and/or steer the resulting beam. Because HPEL panels are an array of many small driver cells it essentially acts phased array transducer. The difference here is that you can't independently control each cell...or can you!?

Here's what I'm thinking: If you change the size and shape of the cells, you may be able to advance and retard the phase of the resulting acoustic signal. Cell shape may make it respond slightly quicker or slower than the panel average. In this way, you may be able to create panels that have differing beam shapes by varying cell shape and size. So, in headphones for example, you could angle the resulting beam rather than angling the transducer itself to make the planar wave approach your ear on a more natural angle. Just a thought.

The Sonoma Model One is a delightful listening experience. It has some distortion problems at high listening levels—especially with big bass drops—and treble response is just a tad too hazy to compete with some reference level headphones on that score. But the overall balance of performance, especially in terms of tonal neutrality, is terrific. I heard no wonky problems like treble spikiness or midrange suck-outs at all. I can't think of any other headphone I can say that about.

Many will complain that $5000 is an outrageous price for headphones...I agree. The Model One is not just a headphone though, it's a very good DAC, correction DSP, and amp. Take your average $4000 headphone: if you don't throw at least another $4000 in amp and DAC at it you're probably wasting money with underperforming very expensive gear. $5000 with the Model One and you've got it all without spending a bunch of time mixing and matching expensive gear to find something just right. On the other hand, that's part of the fun of the hobby and maybe the Model One isn't for you.

Bassheads and people who like to play their music loud need not apply. But if you listen at responsible levels (say 80-85dBspl avg), and are looking for a one-stop, get it and forget it solution for desktop high-res USB listening, this is a must-hear bit of kit.

Over time I came to feel that I simply wouldn't be able to evaluate future electrostatic headphones and systems without being able to compare it to the Model One. It may not have the treble resolve or huge bass thump of some systems, but its overall balance and natural presentation has very few peers. Music listening pleasure is the paramount characteristic for any audio gear in my opinion and the Model One delivers. Headphones should be evaluated on that score, and I'll need the Model One to compare. Up on the Wall of Fame it goes!

Or maybe I just want one around because it sounds so good. It's good to be me sometimes.

Click to view on YouTube.

I enjoyed this SBAF thread.
The Stax Mafia weigh in here.
Too early on for anything but yabber in the Head-Fi thread.

Sonoma Acoustics

Tyll Hertsens's picture
Thanks, Suuup! got a little thump back into estats...long as you don't crank it.
Suuup's picture

Another interesting comparison is This is harman-compensated.

Tyll Hertsens's picture
...damn...that's pretty good.
JimL's picture

Actually, I believe that -70 dB is 0.03% rather than 0.05%. Both are very good.

JimL's picture

Hm, -30dB at 105 dB is 3% 2nd harmonic distortion.

-40 dB = 1%
-50 dB = 0.3%
-60 dB = 0.1%.
-70 dB = 0.03%
-80 dB = 0.01%
and so on - actually, each 10 dB represents Sq rt of 10 decrease = 0.3162x

MRC01's picture

Correct. In case anyone wants to compute it for himself, the formula is: DB volts = 20*log(ratio). The log is base 10, so it's easy to see every factor of 10 is 20 dB. For power it's DB power = 10*log(ratio), so every factor of 10 is 10 dB.

The reason the formula is different for V versus P is for consistency. This way, an X dB difference in voltage creates an X difference in power. If the formulas were the same, an X dB difference in voltage would make a 2X dB difference in power. That's because doubling the voltage doubles the current (since V=IR), which quadruples the power (since P=VI).

GearMe's picture

Your description of the sound reminds me how I felt a long time ago with the Quad ESL-57s compared to the other speakers I owned. For certain types of acoustic music they just had "it"...sounding more real to my ears than any other speakers I've owned. That said, their dynamic range sucked enough that I eventually got rid of them. In hindsight, a dumb decision. ;-)

ab_ba's picture

"Take your average $4000 headphone..." Love it.

Magoo's picture

WOW! $5K for a HP with limited Bass and grainy HF? The DAC has the infamous glare producing ESS Sabre?

Not for me at least...Thanks for the review!

Tyll Hertsens's picture
Seriously, I wouldn't say it had any glare or grain, just a bit hazy. Limited bass level though, for sure.
detlev24's picture

"[...] if you don't throw at least another $4000 in amp and DAC at it you're probably wasting money with underperforming very expensive gear."

That sounds like a commercial for unreasonable expensive gear. Just one example: Take the Focal Utopia, add 50% of its price (~ $2000) and you have it attached to a state-of-the-art amp/DAC, the RME ADI-2 Pro. It will absolutely not be underperforming on this gear and you could even save some bucks by choosing a different combo; if you are not in need of the built-in ADC and EQ.

Of course, you can spend as much (more) money as you want if you subjectively prefer, e.g., the euphonic distortion of tube amps (which could be added to any neutral gear by effects, btw.) or like to have a "design object" to also please your visual stimuli. Again, that is an option but certainly not a necessity to fully power your headphones!

elmura's picture

Whilst $5k ain't cheap, it's within reach of high-end systems, and certainly cheaper than LCD-4 / Utopia etc systems. The fact that the system is tuned to work optimally together using DSP EQ means buyer doesn't need to worry about system synergy, trial and error of different amps / dacs etc. And, I'd bet they will be sending DSP updates in future. I'd like the ability to tune the DSP EQ to suit different hearing (or taste).

I'm interested in this product's future.

MRC01's picture

It seems more like a science project than a product. I love Tyll's open minded optimism & enthusiasm, and as an engineer I respect what they did, but why they chose this kind of driver mystifies me. It seems like they picked an inherently poor driver and did some real brain sweat and engineering to make it sound less bad, ending up with a very expensive product with mediocre performance. I can't help but think that if they applied that same engineering effort to a conventional or ortho driver it would be truly astounding.

Magoo's picture


When will you report on these latest Grado HP's? $2700 and yet built like $30 Hp's?


solrage's picture

I had high hopes for these. $5k for an all-in-one system synergistically designed to work well with each other isn't really outrageous given the price of high-end headphones/amps/dacs out there these days. The frequency response is definitely on point, but those distortion figures make this a no-go for me. On days where I don't plan to listen for very long I like listening >90dB, and even on days where I keep my average level <85dB, a lot of music I listen to--especially orchestral usic--has dynamic peaks over 100dB, so being able to play clean loudly is a prerequisite. Oh well, guess I'll just have to see how the LCD-4/Utopia fiasco turns out... or maybe just wait until some company finally puts out a great headphone that ticks every box. Until then, I'll remain relatively happy with my HD800s, HE-6, and LCD-X combo.

heymamahey1990's picture

People need to make use of what they have. - Steven C Wyer

harry56's picture