Innersound Kaya Reference loudspeaker

Paul Bolin, December, 2004

New experiences are some of the most pleasurable parts of being an audio reviewer. Despite being involved with the High End for longer than I care to think about, I had never had the experience of owning, living with, or reviewing a pair of electrostatic speakers, be they full-range or hybrid. I'd heard various Quads plenty of times at shows and in the homes of audio buddies, but in my own listening cave? Never.

Last May, I suspected that my lifelong electrostatic drought had come to an end when I heard the Innersound Kaya Reference system ($20,000/pair) at Home Entertainment 2004 East, in New York. I was instantly taken by their striking looks and their ability to hold up to even my loudest, most bass-heavy J-pop CDs with no strain. Both John Atkinson and I were impressed, and arrangements were promptly made for review samples to be sent along.

The Kayas arrived in early August, with Innersound's Wes Bender in tow to assist in moving, unpacking, and setup. Compared to some of the mammoth speakers I've had in-house over the last few years, moving and unpacking the relatively svelte Kayas was a piece of cake—the two of us were able to manage it in less than an hour. And you don't even need to charge them up—just plug them into the wall and you're ready to go.

Family values
Anyone familiar with Innersound's speakers (the Eros Mk.III was reviewed by Larry Greenhill in April 2003) will notice that, from the front, the Kaya looks like nothing so much as the Eros on steroids. The Kaya's second-generation Ultra Stat panel is nearly 4' tall, and this accounts in part for its ability to take huge momentary power inputs. Wes Bender explained that the panel is virtually impossible to blow up or damage in real-world listening circumstances. Unlike classic electrostatic drivers, the stators that carry the high voltages necessary to create the electrostatic field are embedded in a proprietary constrained-layer material that provides perfect insulation. This means that the tiny irregularities present on coated drivers cannot act as potential "arc-over" points (think of minuscule lightning rods). Innersound's white paper asserts that the Ultra Stat is entirely impervious to variations in temperature and humidity.

Admittedly, an elecrostatic loudpeaker that doesn't have to reproduce bass is capable of much higher SPLs than one that has to act over the full audioband. But hybrids have their own set of issues. It's no easy thing to successfully mate a necessarily massy dynamic woofer with an almost massless 'stat panel and get the two to sing with one voice.

The Kaya echoes the Eros in its use of a 10" woofer in a transmission-line cabinet to handle frequencies below 350Hz. Innersound's Compact Transmission Line is tapered so that it has an "infinite number of very tiny resonances that are then completely absorbed by special damping material contained within the line." The Kaya's cabinet is larger and more sophisticated than the Eros's, featuring a "unique four-layer laminated back [for] minimal internal reflections and virtually no resonance." A "specially developed 10" low-mass paper bass driver" is used; Innersound says that the driver features a patented magnetic damping system. Said woofer is driven by an external 600Wpc crossover-amplifier that is supplied as a part of the system, so an extra set of interconnects from the crossover amp to the main amp is required, as is biamping of the speaker proper.

The amplifier is remote-controllable for overall volume, as well as low-bass output below 100Hz over a 12dB range; a Midrange control adjusts the woofer's output in the crossover range in 1dB increments. The Kaya amplifier also has one very irritating ergonomic feature—its WBT binding posts (footnote 1) are arranged with their slots at 180 degrees to each other. The tails of my current reference speaker cables, the Cardas Golden References, were not long enough to both cross and reach the slots, so I was forced to use Monster X-Terminator banana plugs with the Cardases. (The X-Terminators had a tendency to pop out of the banana jacks in the center of the amp's binding posts.)

The Kaya's appearance is Scandinavian-modern elegant—tall and slim, with lovely maple veneers and brushed-aluminum facing combining to capture a graceful, light feeling. It's the antithesis of a big, dark, Darth Vaderish box. Side "wings" flow down from the panel's top to the top of the woofer cabinet, and though I could hear a resonance when I tapped the wings' surfaces, that resonance appears to be below the point at which the panel crosses over. John Atkinson's measurements will doubtless ferret out the truth.

Setup was not overly difficult. Innersound designer Roger Sanders has not tried to counteract the natural beaminess of electrostatics at high frequencies, so the Kayas required a considerable amount of toe-in and, for nearfield listening, some back-to-front downtilt. After Wes Bender left, I played around with the Kayas' positions, eventually toeing them in a bit less, so that I could see the merest sliver of the woofer cabinet's side from my listening position. They also liked being placed a bit closer to the front wall than I'm used to. Their final positions were 33" from the sidewalls to the speakers' centers, and 45" from the front wall; this provided a good combination of bass reinforcement and soundstage dimensions.

You're the top
I've listened to a good many excellent dynamic speakers, and have described a few as sounding "electrostatic-like." And some of them did have electrostatic-like qualities—there's no question that, in its phenomenal extension and remarkable (once broken in) sweetness, the beryllium tweeter in Focal-JMlab's latest, Be series of Utopias is the finest dome tweeter I've ever heard.

The Kaya's Ultra Stat panel was also very much the real deal, but as only a great electrostat can be. The Kaya resolved spatial information and instrumental and vocal details with stunning acuity. The more elaborate the music—be it the performance of Liszt's Piano Concerto 2 by Sviatoslav Richter, Kiril Kondrashin, and the London Symphony (LP, Philips 6880 046, footnote 2), or the complex layers of deliciously addictive techno-pop in Sugar's "Heart and Soul" (Japanese CD single, Toys Factory TFCC-89110)—the more the Kaya showed. The Kaya could split hairs to as fine a degree as I have heard from any speaker, and delivered extraordinary and, quite possibly, standard-setting transparency, regardless of the type of music I played through them.

Footnote 1: While they sound perfectly fine, I abominate these plastic-covered, slotted, Euro-nanny terminals more than earaches and watered booze combined. They don't fit a Postman terminal wrench, and I'm always in fear that using an adjustable wrench on them will crack the slick plastic that resists so well any attempt with the fingers to tighten them down firmly.—Paul Bolin

Footnote 2: This gem was recorded by the famous Mercury Living Presence team of Wilma Cozart Fine, C. Robert Fine, and Robert Eberenz.—Paul Bolin



The fine distinctions among players in string sections—the sense of many working together nearly perfectly as one—when playing John Barbirolli and the Sinfonia of London's classic performance of Vaughan Williams' Fantasia on a Theme by Thomas Tallis (CD, EMI 5 67264 2) were uncannily present. Logically, the less mass that has to be accelerated, the more rapidly it can be accelerated, and the Ultra Stat is about as close to having no mass as any driver can be. More intimate music, such as Bill Evans' bittersweet, endlessly inventive reharmonizations of "Suicide Is Painless," from You Must Believe in Spring (LP, Warner Bros. HS 3504), showed another side of the Kaya's marvelous resolution. Tiny, fine points of piano and drums filled the far end of the room with natural warmth, and a level of midrange and treble liveness that was tingle-inducing.

The Kaya played big, bold music, such as Hans Zimmer's score for the film Gladiator (CD, Decca 467-094-2), in big, bold, superbly defined spaces. Their resolution of the hall depth on the Vaughan Williams Fantasia was breathtaking, the antiphonally placed players beautifully focused in a space defined with electrifyingly lifelike expansiveness. The depth of the soundstage on "Journey to the Line," from Zimmer's score for The Thin Red Line, was extremely impressive, the big drums booming into the picture from a precisely defined point far away, albeit with less force than is available from the Focal-JMlab Nova Utopia Be's. The Stan Kenton Band's Standards in Silhouette (rainbow-label LP, Capitol ST 1934) was recorded in a cavernous space that the Kayas wrapped lovingly around my room.

Timbral colors benefited from the same serene microresolution as did spatial characteristics. The multitude of fretted instruments used by Ry Cooder in "The Pearls/Tia Juana," from Jazz (LP, Warner Bros. BSK 3197), were superbly individualized. Through the Kaya, sounds that seemed piled atop one another even through excellent speakers were neatly separated. The way the Kaya handled vocal sibilants was a textbook lesson in how to do it right. There was never any additional heat unless it had been recorded in the source material. The inimitable Frank Sinatra was as subtle as life, the wear and tear in his voice just beginning to become apparent, but the command still there in "Follow Me," from Francis A. Meets Edward K. (LP, Reprise FS 1024). If you don't have this wonderful album, you're missing one of life's great treats.

The distinctive quality of the cellos and basses digging in at the beginning of the third movement of Vaughan Williams' Symphony 3, as performed by André Previn and the LSO (UK LP, RCA SER 4659-55), was exceptional—in fact, stringed instruments of all kinds had a uniquely alive quality. The acoustic guitar that introduces Armin van Buuren's "Never Wanted This," from 76 (CD, Ultra L 1168-2), was delightfully delicate and sensitively rendered. The array of acoustic and electric guitars and bouzoukis on Moving Hearts' "Hiroshima Nagasaki Russian Roulette," from Moving Hearts (UK LP, WEA K 58387), rang clear and true.

Transient response was, as should be obvious from the foregoing, phenomenal. The stray-dog bark of Keith Richards' guitar introduction to "Can't You Hear Me Knockin'," from Sticky Fingers (LP, Rolling Stones FC 40488), had the presence and snap of an amplifier sitting in the room with me. Oscar Peterson and Count Basie's The Timekeepers (LP, Pablo 2310-896) presents a different and even more challenging contrast and test. Basie's sparse, wry statements and Peterson's dizzying arabesques demand very different types of articulation for each man's style to be fully realized. The Kaya loved this music, capturing every nuance, foot tap, and hum, and every last bit of the masters' idiosyncrasies and nuances. The leading edge of the acoustic guitar on "Never Wanted This" sounded completely natural. And even with all hell breaking loose around them, Adrian Belew and Robert Fripp's unthinkably complex counterpoint in the first section of the title track of King Crimson's The ConstruKction of Light (CD, Virgin 49361 2) had the calm, centered precision of a Japanese rock garden.

Even given the Kayas' strengths, their imaging stood out as something special. With Francis A. Meets Edward K., Sinatra hung in the air, a vividly life-sized, three-dimensional presence, the Duke Ellington orchestra's sumptuous tones and swinging rhythms surrounding him with equally lush palpability. Anything recorded with any sense of what music actually sounds like came through the Kayas with touchable solidity. Placement precision and boundary definition were the equals of, and on some recordings superior to, the Nova Utopias'.

The panel's dynamics were exceptionally good over all of its range. Its high power-handling capacity and lightning-strike speed allowed it to be driven hard. As panel speakers usually require a little more oomph than their sensitivity specifications suggest, this is a good thing. I could play the Kayas at completely unreasonable loudness levels, and they never started to sound in any way forced or overstressed on anything I hit them with. Your mileage may vary, but I can guarantee that they'll play loud enough to damage your hearing, should you so desire.

I did need to listen on axis or pretty darn close to it—there was a considerable venetian-blind effect off-axis, and way off axis the Kayas sounded just plain weird. Which is why Innersound tells you to set them up the way it does. So there.

Bassic inquiries
With the woofer and panel wired in the same polarity—see later—the Kaya's bass was at first a bit disappointing, given the stellar quality of the electrostatic panel. I often found that I had to readjust the bass and midrange levels from recording to recording. Most often, the bass level was set at 9 or 10 (the range is 0-12), the midrange level between 85 and 87 (the range is 0-99). Even changes of a single increment made a substantial difference in bass balance and the clarity of the crossover range. I never felt that there was an ideal balance between the woofer and the panel—the sound always seeming to be a jot too lean or a dash too full.

The woofer itself did go down low, though without every bit of the panel's wideband dynamic ease. When a lot of large bass instruments were all firing away at once, as in the Gladiator soundtrack, things got a little muddled. Really big bass transients, such as the synth detonation that opens "Sweetest," from Sugar's Double Rainbow (Japanese CD, Toys Factory TFCC-81650), didn't have the impact I would have expected. A 10" woofer is being asked to do a lot of heavy lifting when it's the only bass driver in a system touted as a broadband, reference-quality speaker. It seemed as though the Kaya's bass driver had been voiced to sound just a bit polite and "electrostatic" in character at the "starter" settings suggested by Innersound for the crossover amplifier. Nudging the controls up too far only thickened the sound, though never to an unpleasant level—unless I stood on the gas pedal too hard.

Experiments in polarity
JA suggested, based on his measurements of the Innersound Eros Mk.III, that I try reversing the polarity of the Kayas' electrostatic panels. The result was more than slightly surprising. Previously, for optimum balance, the midrange and bass controls had demanded to be tweaked for each recording. Now, with the polarity flipped, a midbass anomaly that was likely room-related instantly vanished, and the Kayas' performance through the upper midbass and lower midrange dramatically stabilized. I was now able to leave the bass set at 8 and the midrange control at 84, and things always sounded right. More unusual was that the deep bass was now substantially extended and clarified on such powerful synthesizer parts as that on Sugar's "Sweetest" and "Heart and Soul."

I'm stumped as to why this should be the case. Whatever—what had been a bit iffy was now solid and powerful. The longer I think about it, the more probable it seems that the integration between the Kaya panel and woofer outputs and the interaction between both outputs and the room acoustics mean that the optimal polarity will be different in different rooms.

I will report further on these differences in the near future.

Kaya con dios
The Innersound Kaya Reference does many things well, some spectacularly so. The electrostatic panel's transparency, offhand ability to retrieve the tiniest bits of spatial and tonal information, and astoundingly holographic imaging are all extraordinary, as is its way with voices. The Ultra Stat panel is a classic of its kind, and a sterling performer. For 20 thou, I'd still like to hear a bit more clarity in the deepest bass, especially when the going gets heavy; but then, I'm a devoted fan of bass-heavy music.

For those who prefer less difficult material, the Kayas' musicality and versatility in adapting to a variety of system and room configurations will likely outweigh their inability to pressurize a room with quite the same authority as such monsters as the Focal-JMlab Nova Utopia Be. That at long last there's an electrostat hybrid that can be played at house-party volumes without compromising its greatest strengths is something to celebrate.

Sidebar 1: Specifications

Description: Two-way, biamplified hybrid loudspeaker with crossover-amplifier for bass drivers. Electrostatic Panel: 13" by 45". Momentary power-handling capacity: 1000W. Impedance: 4 ohms nominal, 2 ohms at 20kHz. Woofer: 10" paper-cone unit in transmission-line enclosure. Momentary power capacity: 600W. Nominal impedance: 4 ohms. Amplifier-crossover: Crossover: 350Hz, 24dB/octave. Maximum output power: 600Wpc into 4 ohms (24.8dBW). Input impedance: 47k ohms. Output impedance: 0.1 ohm. Distortion: ±0.05% at rated output. Frequency response (without crossover function): 10Hz-80kHz, ±0.1dB. Overall System: Frequency response: 24Hz-27kHz, ±2dB. Sensitivity: 98dB/2.83V/m.
Dimensions: Loudspeaker: 74" (1897mm) H by 16" (410mm) W by 19" (487mm) D. Weight: 116 lbs (52.7kg) net, 141 (64.1) lbs shipping. Crossover-amplifier: 17" (436mm) W by 5.5" (141mm) H by 15" (385mm) D. Weight: 42 lbs (19.1kg) net, 47 lbs (21.4kg) shipping.
Loudspeaker finish: Maple veneer with brushed aluminum trim (loudspeaker); brushed aluminum with blue display panel (crossover-amplifier).
Serial numbers of units reviewed: None present.
Price: $20,000/pair. Approximate number of dealers: 12.
Manufacturer: Innersound, 2400 Central Avenue, Suite L, Boulder, CO 80301. Tel: (720) 210-1925. Fax: (303) 413-1088. Web:

Sidebar 2: Associated Equipment

Analog source: SOTA Cosmos Series III turntable, Graham 2.2 tonearm, Dynavector XV-1S cartridge.
Digital source: Classé Omega SACD/CD player.
Preamplification: Manley Labs Steelhead phono stage, VTL TL-7.5 Reference line stage, McIntosh C200 preamplifier (as line stage).
Power amplifiers: Lamm ML1.2 Reference and McIntosh MC501 monoblocks.
Cables: Phono: Hovland Music Groove 2. Interconnect: Cardas Golden Reference, Nordost Valhalla, Acoustic Zen Silver Reference. Speaker: Cardas Golden Reference, Innersound. AC: Shunyata Anaconda Alpha & Anaconda vX, Siltech Ruby Hill, Wireworld Silver Electra III+.
Accessories: Shunyata Hydra 8 (front end) and Hydra 2 (amps) power distribution & conditioning; Grand Prix Audio Monaco, Ultra Resolution Technologies Bedrock stands; Ganymede isolation footers; Caig Labs Pro Gold; Walker Audio SST silver contact enhancer; Ayre/Cardas IBE system-enhancement CD, Cardas Frequency Sweep & Burn-in LP; Argent Room Lenses, Disc Doctor & LAST Labs record-care products.—Paul Bolin

Sidebar 3: Measurements

The Innersound Kaya was more sensitive than I was expecting, at an estimated 89dB/2.83V/m. However, this is way lower than the specified 98dB. Because the woofer and the electrostatic panel are driven by separate amplifiers, I have shown the impedance graphs for each separately. Fig.1 shows that of the panel. It is generally very high, staying above 50 ohms between 225Hz and 1950Hz. However, it plummets in the high treble, reaching a minimum value of 0.5 ohm at 29kHz, which is probably the series resistance of the speaker cable and the internal wiring. There is also an amplifier-punishing combination of 3.3 ohms impedance and a -79 degrees electrical phase angle at 15kHz; both this and the virtual short circuit at 28kHz will lead to problems with amplifiers incapable of sourcing current into these kinds of loads. In addition, the huge variation in impedance in the audioband will give rise to a massive modification of the speaker's frequency response with any amplifier other than a modern solid-state design with a vanishingly low source impedance. Use a classic tube amplifier and the high frequencies will be missing in action!

Fig.1 Innersound Kaya, electrostatic panel, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

Turning to the woofer bin, its impedance magnitude and phase angle are shown in fig.2. Remember, there is no passive crossover; the rise in magnitude above the midrange is therefore due to the voice-coil inductance. Overall, the impedance stays above 4.5 ohms, meaning that the woofer will be fairly easy to drive. Note the single peak at 46Hz, implying that the woofer acts as if it is in a sealed box. The big, rectangular port at the base of the enclosure appears to be the termination of a true transmission line, not a reflex vent.

Fig.2 Innersound Kaya, woofer, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

The wrinkles in the woofer impedance plot are due to cabinet resonances of various kinds. Because the woofer is driven via an external crossover (footnote 1), the higher-frequency modes are unlikely to be excited. However, I did find resonant modes present on all the surfaces, at 172Hz, 240Hz, 340Hz, and 500Hz. Fig.3, for example, shows a waterfall plot calculated from an accelerometer fastened to the center of the sidewall level with the woofer—a fairly strong ridge of delayed energy can be seen at 172Hz. (The woofer was driven by the crossover-amplifier for this measurement, as it would be for music.)

Fig.3 Innersound Kaya, cumulative spectral-decay plot calculated from the output of an accelerometer fastened to the cabinet's side panel level with the woofer (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The fairly high frequency of 46Hz for the woofer's box tuning frequency would result in a limited low-frequency extension without any equalization. This is shown by the black trace in fig.4, which is the nearfield response of the woofer driven by a conventional power amplifier. Without a low-pass filter, the response extends up to the 1kHz limit of the graph, while in the bass, the woofer starts slowly rolling off below 120Hz, reaching -6dB at 55Hz. The colored traces show the woofer's nearfield response, but now driven with the Innersound crossover-amplifier. The Midrange control, which sets the woofer level, was set to "90," the Bass control first to "0" (the lowest trace, identical to the response without the crossover), then to all the levels from "1" to "12" (top, colored traces). It can be easily seen that the crossover-amplifier both rolls off the midrange—reaching -12dB at 500Hz—and allows the woofer's bass response to be extended down to -6dB at 20Hz. With the usual boundary reinforcement in a typical room, the Kaya's bass extension will reach 20Hz.

Fig.4 Innersound Kaya, nearfield response of woofer without crossover (black) and with crossover bass control set from "0" to "12" (colored traces).

Fig.5 shows the individual responses of the port (blue trace), woofer (red), and electrostatic panel (green), the latter two traces being composites of the nearfield response at low frequencies and the on-axis farfield response at high frequencies. Actually, the large size of the electrostatic panel means that the microphone is not actually in the farfield when placed at my usual measuring distance of 50", which results in the slight downward tilt in the upper midrange that can be seen in the panel's output. Other than that, the Kaya's on-axis output is fairly smooth and flat. The various peaks below the panel's passband are due to the different drumhead resonances of a tautly stretched diaphragm. The fundamental diaphragm resonance lies at 76Hz, but is effectively suppressed by the crossover. It will be excited by the woofer to some extent, and I could hear it coloring my voice when I spoke close to the panel. (This is what Paul Bolin heard when he rapped the speaker's side cheeks.) I wonder if this contributed to the occasional "muddling" Paul noted in his auditioning.

Fig.5 Innersound Kaya, acoustic crossover on center-of-panel axis at 50", with the nearfield responses of the panel (green), woofer (red), and port (blue), weighted in the ratio of the square roots of the radiating areas.

The crossover to the dynamic woofer takes place at 400Hz, though this will be affected by the setting of the Midrange control. With the Bass set to "12," the LF response extends down to the lowest bass. There is no minimum-motion point, confirming that the woofer doesn't act as if it is reflex-loaded. However, there is some output from the port (blue trace), disturbed by slight peaks at the frequencies of the wrinkles in the impedance traces. These are well down in level, however, and shouldn't affect sound quality.

My usual practice is to show a speaker's farfield response averaged across a 30 degrees horizontal angle centered on the listening axis. I have done this for the Kaya in fig.6, which appears to show a catastrophic lack of treble. However, this is almost entirely due to the fact that a large, flat diaphragm becomes extremely directional in the treble, something that is graphically shown in fig.7, the speaker's lateral radiation pattern. Only the differences between the off- and on-axis responses are shown in this graph. Basically, you need to sit within a couple of degrees of the panel's centerline to get a full measure of high frequencies.

Fig.6 Innersound Kaya, anechoic response on center-of-panel axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with the complex sum of the nearfield panel, woofer, and port responses, taking into account acoustic phase and distance from the nominal farfield point, plotted below 300Hz. (Panel connected in inverted polarity.)

Fig.7 Innersound Kaya, lateral response family at 50", normalized to response on center-of-panel axis, from back to front: differences in response 90 degrees-5 degrees off-axis, reference response, differences in response 5 degrees-90 degrees off-axis.

In the vertical plane (fig.8), the Kaya's balance doesn't change significantly with listener height, due to its radiation pattern taking on some of the character of a line source. Both this graph and fig.6 were taken with the polarity of the panel inverted, which gave the best frequency-domain integration of the woofer and panel outputs. A crossover suckout develops at extreme high or low positions in this graph; with the same polarity connection, this suckout develops on the listening axis.

Fig.8 Innersound Kaya, vertical response family at 50", normalized to response on center-of-panel axis, from back to front: differences in response 10 degrees-5 degrees above axis, reference response, differences in response 5 degrees-15 degrees below axis. (Panel connected in inverted polarity.)

To investigate why this should be, I plotted the farfield step responses of the woofer and ELS panel separately in fig.9, with both connected in positive acoustic polarity. The panel's step (red trace) features a coherent right-triangle shape, but with some significant lower-frequency ringing present. The blue trace is the woofer step, and it can be clearly seen that its initial rise away from the time axis is opposed by a negative-going section of the panel step's tail. This correlates with the frequency-domain cancellation in the lower midrange on the listening axis.

Fig.9 Innersound Kaya, step response on center-of-panel axis at 50" of electrostatic panel (red) and woofer (blue), both connected in normal polarity (5ms time window, 30kHz bandwidth).

Inverting the panel's output gives the step response of the complete speaker shown in fig.10: the decay of the panel step now smoothly hands over to the start of the woofer's step, which results in better frequency-domain integration of the two units. Whether this is preferred or not will depend on the listening room's acoustic and the height of the listener's chair. I note, however, that PB preferred the Kaya's midrange presentation with the panel and woofer in opposite polarity. Kaya owners should experiment for themselves.

Fig.10 Innersound Kaya, step response on center-of-panel axis at 50", panel connected in inverted polarity (5ms time window, 30kHz bandwidth).

Finally, fig.11 shows the Kaya's cumulative spectral-decay plot, measured in the farfield. Other than a ridge of delayed energy between 16 and 17kHz that coincides with a response peak, the delay of the impulse is much cleaner than I usually find with panel speakers.

Fig.11 Innersound Kaya, cumulative spectral-decay plot at 50" (0.15ms risetime).

Some of the Innersound Kaya's measured behavior is idiosyncratic, but whether or not this will result in audible problems will depend on how the speaker is set up, and whether or not the partnering amplifier can cope with the difficult load. Certainly, in my own auditioning of the speaker at recent shows, I have been very impressed with the accuracy and stability of the imaging and the clean, well-balanced sound—as long as I sat in the sweet spot!—John Atkinson

Footnote 1: The Kaya's crossover-amplifier is similar to that provided with the Innersound Eros loudspeaker; see for its measured performance.—John Atkinson



Paul Bolin wrote again about the Kaya in May 2005 (Vol.28 No.5):

Toward the end of my original audition of the Kaya, John Atkinson suggested that I experiment with the polarity of the speaker's electrostatic panel. Much to my surprise (as mentioned briefly in my December 2004 review of the Kaya), inverting the polarity of the panels of both left and right speakers had a drastic impact on the speaker's sound. With both woofers and panels connected in conventional polarity, the Kaya, at least in my room, had some problems in the upper bass/lower midrange. There had been a substantial suckout of the upper bass and, for reasons I could not fathom, the lowest bass seemed softer and less defined than I had expected, as well as lower in level.

The changes wrought by reversing the polarity of the electrostatic panel made a tremendous difference in the speaker's sound. The upper bass, where cellos and male voices reside, acquired a natural and surprisingly lifelike authority, especially for a system that relies solely on a single 10" woofer for frequencies below 360Hz. It seems likely that an infelicitous interaction between my listening room and the Kaya—especially given that this problem was most noticeable in the crossover range—was to blame for the "in-phase" problems.

What I found much more difficult to explain was that the lowest bass—such as the synthesizer bass on techno-pop and the massive five-string electric bass guitar on Eleanor McAvoy's "I've Got You to See Me Through"—was transformed. The bottom octaves had sounded soft and ill-defined, if surprisingly deep. With the polarity flipped, the Kayas became capable of room-shaking depth—not at the level of the Focal-JMlab Nova Utopia Be, but far more than merely respectable when the going got low. Perhaps, with everything in phase, there was a comb-filtering effect that muddied and canceled the extremes of low bass. That something was going on was plain to hear—my polarity experiments also resulted in a dramatic tautening-up of the lows. Deep bass is fine, but well-defined deep bass is better still—and the Kaya was capable of delivering it.

All of this suggests that the Kayas may take a bit more experimentation than some other speakers before their performance is maximized. They assuredly are not "plunk 'em down and play" speakers. But most top-shelf speakers benefit from extra care taken in setup. Usually, this care involves persnicketiness in placement, but the Kayas add an extra step: attention must be paid to what polarity works best in any given room. The results are worth the effort.—Paul Bolin