1000i Electrostatic Loudspeaker
An evolution of the electrostatic
Review By Dick Olsher
here to e-mail reviewer.
It is fair to say that electrostatic loudspeakers gained traction in the marketplace during the 1950s. Everyone seems fixated on Peter Walker's 1957 launch of the QUAD ESL as the art's commercial inauguration. But in hindsight it was our own Arthur Janszen's four-element model 1-30 electrostatic tweeter array that introduced music lovers in 1954 to the transient magic of a force-over-area design with vanishing low moving mass. Even in those days Janszen liked to dispute the fashionable assertion that the loudspeaker was the weakest link in the audio chain. He showed that electrostatics were capable of adding less distortion to the signal path than many phono playback systems, tape decks, or some amplifiers. And that in a nutshell has been the ESL's main attraction, which is no doubt responsible for the loyal following it has enjoyed over the years. ESLs have been in continuous production, in one form or another, for some 60 years. And that speaks volumes for the technology's performance attributes.
Fifty years have passed in the interim and you would think that innovative ideas would have by now run dry, that all worthwhile technological improvements would have been exhausted. Well, not exactly. Enter Final Sound. The Dutch company was founded in 1991and began building their first electrostatic speakers as "hybrids". During the 1990s, Final was basically an audiophile company, but in 2004 after the company was sold to a group of new investors, the newly restructured
company developed a key new patent which facilitated a line of affordable, modular, and lightweight ESLs, market focus was expanded to include the hot segment of home theater.
The 1000i represents Final's flagship product, a 6.5-foot tall line source. Despite its rigid extruded alloy frame, the panels are fairly light (at least by audiophile standards). And although I had little trouble maneuvering the panels and sitting them down over their bases, it's probably safest to enlist someone's help during this process. During the setup process, lugs on the bottom of the panels need to be aligned with matching cutouts in the feet, and this can be a bit tricky. Once the set screws in the feet are tightened, the panels tilt back slightly, which made me a bit nervous at first until I realized that it's the most stable configuration for the tall panels. Be sure to locate the bases pretty much where you'd like the speakers to be positioned, as they are difficult to move around without first removing the panels from their bases. Despite their height, the panels look sleek and elegant and are certainly less dominating visually than say a pair of Sound Lab model A-1 electrostats.
Conventional electrostatics apply the DC bias voltage to the central diaphragm, typically a thin conductive Mylar film, that is sandwiched between acoustically transparent stator panels (e.g., perforated metal plates). The audio signal is stepped up to a high voltage by the input transformer and applied to each stator with opposite polarity. The resultant electrostatic forces applied over the diaphragm's area cause it to be pushed and pulled in unison toward the stators.
Final Sound inverts the function of the transducer elements, a design patented under the name "Inverter Technology." The audio signal is applied to a 12 micron thin diaphragm which is made conductive via a proprietary coating process that also makes it resistant to environmental contaminants. The perforated metal stators are insulated with a coating of special epoxy polyester. One of the benefits of this technology is enhanced safety: no high-voltage AC signal is applied to the stator panels; the point being that a DC polarizing voltage stresses the insulation far less than would an AC signal. Another significant advantage is that the required input transformer size decreases, as the stepped-up audio signal can now be applied just to the diaphragm in single-ended fashion. Recall that traditional designs require a push-pull signal for the stator panels, and hence a beefier transformer core. Final has developed its own high-grade audio transformers partly because they have been unable to identify suitable off-the-shelf transformers, but mainly because this is a critical component, largely responsible for the overall performance of the speaker.
Several other design elements are worth our attention. There are two audio inputs to the diaphragm. The conductive layer features a separate narrow treble strip, which is being driven from its own transformer secondary winding. This improves treble dispersion and reduces the load capacitance at high frequencies. Spacers are used to break up the diaphragm into several regions for resonance control. In addition, and this idea is both new and patented, the spacing between the stators and the diaphragm at the bass side of the panel is greater than that at the treble side. Recall that electrostatic forces decrease as the square of the distance. Doubling the spacing requires a force four times as large to maintain the same efficiency. Final's technology significantly increases bass excursion capability without reducing efficiency in the midrange and treble.
Conventional electrostatics dip well below 2 Ohms in the extreme treble. It's a function of the panel being essentially a giant capacitor, which rapidly drops in impedance with increasing frequency. The higher the panel's capacitance the worse the problem becomes. The 1000i (as well as the other ESLs in the line) bucks the trend and maintains a respectable minimum impedance in the extreme treble. Ronald Buining, one of Final's designers and engineers, explained that since the treble is emitted by a narrow strip, the speaker's capacitive loading is reduced. And it is primarily the reduced capacitance that is responsible for the impedance magnitude remaining at about 2 Ohm around 20kHz for the 1000i. I agree with his take that such an impedance magnitude should not give amplifiers trouble in terms of power delivery as the music's power spectrum drops steadily with increasing frequency. There simply isn't much energy in the treble to begin with. However, it is still important to mate the 1000i with low source-impedance power amplifiers to minimize frequency response deviations due to interactions of the power amplifier's source impedance with the speaker's impedance curve. High source impedance tube amplifiers could easily result in treble loss with this speaker. In the bass, the impedance is generally above 10 Ohms with a prominent peak of 100 Ohms around 40Hz, again an easy load for a power amplifier.
A little bit of reflection will make it clear that it is possible to position the panels with either the narrow (treble) strips on the inside or on the outside. The User Manual is clear on this point: the speakers need to be positioned so that the narrow strips are on the inside, and that's how I conducted all of the listening sessions. The treble sweet spot is still fairly small laterally and the speaker benefits from being toed-in toward the listening seat. The last thing you should do is point the 1000i straight out so it is parallel to the rear wall. The manual is also quite clear about the need to allow some breathing space behind the speakers and that distance from the rear wall will influence the bass response as well as the soundstage. That's good advice for any speaker type, and is especially critical in the case of a dipole radiator.
In general, bass output increases as the speaker approaches the rear wall while soundstage depth perspective and spaciousness decrease. As a rule of thumb, a spacing of about five feet makes for a good starting point, giving the soundstage sufficient scope to expand and fill the space behind the speakers. I can't imagine being happy with either the spatial impression or the resultant loss of clarity due to early reflections when the spacing is reduced to below about three feet. Having said all that, it bears emphasizing that it is important to experiment with both the placement and toe-in angle of the 1000i. Time spent tweaking the speaker's position is definitely worthwhile, as even an adjustment of a mere foot can smooth out the midbass and gives you a chance to optimize the all important tonal balance.
After just a few bars of Bach's Concerto for Violin, Strings and Continuo in E Major with soloist Hilary Han (DG SACD 474639-2) I knew I was in love with the 1000i's harmonic character and drive. It simply boogied along with plenty of speed and control. It brought back vivid memories of my first close encounter with a QUAD ESL-57. To confess, I was awe struck by a speaker that appeared to open a window onto a live performance. In the immortal words of Yogi Bera, it was a case of déjà vu all over again. The star attraction was an utterly transparent and intimate midrange. There was nothing laid back or timid about it. The harmonic envelope of each musical instrument ebbed and flowed naturally, cohesively and with fantastic transient precision. Think for a moment about how artificial most conventional box speakers are in their portrayal of the harmonic envelope. For example, a paper or plastic midrange cone which is augmented by a metal dome tweeter. In this case, the harmonic structure of say a violin is pieced together by two drivers of disparate sound quality, distortion products, and dispersion characteristics. What are the odds of such a speaker producing a realistic impression of a violin? Not good, in my opinion. In contrast, we have here a line source electrostatic that speaks with one voice, and I think that's a pre-requisite for approaching the harmonic and spatial impression of live music.
The tonal balance was surprisingly full bodied. The warmth region, closely associated with the upper bass range (160Hz to 320Hz), was nicely fleshed out without any hint of the anemia I experienced recently with the MartinLogan Vista. These are not bright sounding speakers and they tolerate less than perfect recordings well without exacerbating an already hot upper range. So often in the world of pop recording tracks are equalized for added presence in the 8kHz to 12kHz range, a practice that can really set off fireworks with many dome tweeters. In contrast, the 1000i's extreme treble seemed so smooth yet slightly rolled off in level relative to the midrange. The overall impression was that of a concert hall, middle-row perspective. This is the sort of balance that serves classical music and jazz very well, framing the midrange more clearly and establishing a firm orchestral foundation. Its sound truly is a safe haven in a world run amuck with mediocre multi-way box speakers.
The transition from the midrange to the presence region, around 3kHz, which is problematic for two or tree-way box speakers, was totally seamless. Violin and soprano harmonic textures were reproduced with exemplary sweetness, sheen, and clarity. There was plenty of low-level detail to behold; it's just that it was never in your face. It was there, like pebbles visible through a layer of crystal clear water, much like the sensation of live music and so much unlike the relentless, etched presentation audiophiles sometimes fall in love with. I recall an Infinity speaker from some 20 years ago, a tall baffle with line arrays of mid and treble units, which was so raw in the treble that it was practically painful. A makeshift solution was implemented to alleviate the torture: masking tape over a couple of the Infinity's treble units - a clear demonstration that sometimes less is better!
I don't think the deep bass in my room extended much below 50 Hz, but with a well defined midbass and a strong upper bass range the 1000i did well with cello and acoustic bass. Bass lines were generally well defined and gutsy but lacked the ultimate in punch, an issue with all full-range electrostatics known to me. An optional powered subwoofer (model S220) is available, and a review sample was actually provided. But I just said no to a review of a subwoofer in this context, which would have been tantamount to mixing apples and oranges. First of all, I don't think the 1000i really needs a subwoofer unless
it is part of a home theater system expected to reproduce deep bass special effects. And second, in my experience adding a subwoofer to an electrostatic generates more problems than it cures by creating serious integration issues. To name just one: the resonances of a box woofer mixed with the speed of an ESL.
To be blunt, I was seriously concerned about the dynamic performance of the 1000i at altitude. My listening room is located at 6,400 feet - half way between sea level and a good vacuum. Of course, a perfect vacuum would make for a good insulator, but at my altitude corona discharge problems are at their worst. Living with the Sound Lab A-1 for many years meant having to seriously back off the bias voltage in order to quiet down the crackling noise. And by then A-1's sensitivity was really in the toilet, making it difficult to obtain loud playback levels. For the record, the 1000i was extremely quiet without any snap crackle or pop to interfere with the enjoyment of quiet passages. And I was able to scale the dynamic range from soft to loud with respectable conviction, though a good 100 wpc amplifier helps significantly in this regard. I can confidently recommend James Bongiorno's Son of Ampzilla 2000 as an excellent match for the 1000i.
The champ though, in the price-no-object category, was the LAMM Audio Laboratory M1.2 Reference. Its low source impedance (under 0.1 Ohm) was instrumental in coaxing the most extended treble out of the 1000i. And it, more than any other amplifier on hand, made the 1000i sing in breathtaking fashion. Note that at no time did I feel that I was endangering the speaker driving it as I did with a high-power amplifier
— a situation well familiar to QUAD 57 owners. And of, before I forget, I should add that I am a proud owner of a pair of refurbished QUADs
(QUADs Unlimited obtained via Electrostatic Solutions), and that the Final Sound ESLs completely blow them away in terms of large scale dynamics.
I freely confess a bias toward the spatial presentation engendered by planar speakers. Many audiophiles, especially the baby boomers among us, were weaned on minimonitor sound and expect nothing short of pinpoint imaging. Does live music live up to the paradigm of pinpoint image outlines? To answer that question, close your eyes next time you're at a live musical event and try to visualize the musicians on stage. You may be surprised to realize that instruments actually possess spatial extension, width and height that are not accurately portrayed by conventional box speakers. A planar dipole speaker does a much better job of floating a realistic spatial impression, and one reason is its ability to emulate the surface loudness density of instruments with large sounding boards.
A piano, for example, generates a lot of acoustic power, but it is spread out over a large sounding board yielding a low surface loudness density. And this is one of the perceptual attributes associated with piano sound. On the other hand, a trumpet's surface loudness density is at the opposite end of the spectrum - a lot of power concentrated in a small volume and that is partly responsible for the perception of a piercing sound. While conventional box speakers typically manage no better in terms of image size than midget musicians, Jedi Master Yoda and his cousins arrayed across the soundstage, the 1000i by virtue of its large surface area was able to float image sizes with realistic extension and height perspective. The impression of a soloist standing front and center within the soundstage was quite strong. When properly setup with respect to spacing from the rear wall, image outlines snapped into focus. It was easy to resolve individual voices in a chorus. Soundstage width and depth perspective were nicely delineated without having to resort to side and rear wall treatment as I was forced to do with the Sound Lab A-1.
To my way of thinking, the Final Sound 1000i represents a milestone in the evolution of the electrostatic loudspeaker. It is a reliable, real-world ESL, whose musically expressive personality has won me over in spades. Its harmonic purity, tonal realism, and dynamic range meet the needs of most musical genres. If I had to live with only a single ESL
— cost no object — the 1000i would be my top pick. A must audition for any ESL aficionado and anyone serious about approaching the live experience at home.
Type: Electrostatic loudspeakers
Frequency Response: 38Hz to 20kHz (± 3dB)
Nominal Impedance: 4 Ohms
Recommended Amplifier Power: At least 75 wpc
Dimensions: 78.3 x 14.2 x 2 (HxWxD in
Weight: 50.5 lbs each
Price: $9,999/Pair (Chrome Finish); $11,000/Pair in Piano Black
Final Sound Solutions B.V.
5466 AC Veghel
Voice: +31 413 375 412
Fax: +31 413 369 070
United States Headquarters:
Final Sound USA
500 West Cummings Park
Woburn, MA 01801
Voice: (781) 938-6416