"In-Wall Speaker Test, Part 3"

by Keith Yates

Subjecting 20 putatively “high-end” in-wall speakers to the same performance standards used to judge conventional in-room speakers proved to be something of a novel idea back in the February and March ’96 issues. The responses those twin installments provoked were fascinating, though, in retrospect, probably predictable.

Manufacturers whose flagships fared poorly tended to opine that it was folly to take the in-wall breed so darned seriously. Several, in fact, openly dismissed in-walls as doomed never to amount to anything more than background music reproducers. Most of those whose speakers ended up in the middle of the pack acknowledged that they had work to do: “Give us 12 to 18 months and we’ll rule the roost,” predicted one eager marketing fellow. (I don’t know the current status of that company’s efforts; he was sacked a few months later.)

And the handful whose in-walls proved competitive with similarly priced in-room models simply smiled, presumably content to watch the purchase orders roll in while quietly parceling out more resources—engineering talent, R&D funds, tooling—to close the remaining gap between the lifestyle-friendly in-wall and its bookshelf- and freestanding-type cousins.

With the hubbub all but died out, I was itching to find out how far the state-of-the-art in in-wall speakers may have come in the 2-year interim. I polled a couple of fellow listening-room and home-theater acoustics designers, some dealer/installer friends and a few independent loudspeaker engineers to ferret out “the contenders” from the “wannabes,” ordered up the review samples, and put them through the same grueling review process. [See “Testing In-Walls” for details.]

The AWM70 is the top model in an ambitious new series from B&W designed to offer quality-oriented consumers a compact, elegant, house-wide means of producing high-quality music. Known as the CASA (Custom Active Sound Assistant) system, the core components include a central system controller, one or more wall-mounted keypads, remote handsets and active (that is, internally-amplified) in-wall speakers.

The system’s plug-and-play design permits any of up to 16 sound sources to be routed to up to 64 zones. The keypads allow the user to choose the source (CD, radio, tape, etc.), control its basic functions (CD tracks, radio presets etc.), make volume adjustments, check the time, and program turn-on and turn-off times. A small infrared “eye” in each keypad and speaker can relay commands from the remote handset back to the central control unit. The speakers themselves connect to the control unit via a standard Category 5 cable terminated with RJ-45 connectors.

As the reader has probably gathered, their unique design makes the AWM70s useless outside of the context of a complete CASA system, dependent, as they are, on the central controller to work. Consistent with the speaker focus of my test, I ordered the skeletal configuration (1 pr. of speakers, 1 central controller and 1 keypad) and restricted my evaluation to the quality of sound that came out of the AWM70s; no doubt some readers will be keenly interested in broader applications of the system’s multiroom/multizone features as well.

The flagship speaker in the CASA collection, the English-made AWM70 appears to be a “turbocharged” version of the B&W Signature Seven, the in-wall that, along with the more expensive Triad InWall Gold system, ended up at the top of the pile in my previous round of tests [see “In-Wall Speaker Test, Part 2,” March 1996].

Outwardly resembling the Signature Seven, behind its nondescript grille and distinctive grooved front baffle the AWM70 boasts a purpose-built active crossover with built-in spectral shaping (equalization), a dedicated 100-watt amplifier for the 7-inch woven Kevlar woofer, and another 100-watt amp for the 1-inch metal dome tweeter. All that circuitry draws both its power and audio signal from the central control unit through the Cat-5 cable.

The audio feed itself is delivered in balanced format, which suppresses noise and distortion from contaminating the signal on its way from the controller. From an engineering standpoint, the whole arrangement is very sensibly conceived and executed, offering near-ideal electrical intimacy between the amplifier’s output stage and the speaker’s voice coil, which is barely an inch away. Since the hot-`n-heavy, high-voltage part of the amplifier is tucked away in the central controller, the crossover/amplifier/speaker package is a low-voltage, cool-running affair and, in fact, has been approved by various regulatory agencies for in-wall use.

B&W rates the AWM70’s response as 38Hz-20kHz, plus or minus 3 decibels. As with the Signature Seven, installation was straightforward and glitch-free. Fit and finish appear to be excellent.

On audition, the AWM70 made an overwhelmingly positive impression, from the 500-year old “Danza Alta” to the Wallflowers’ “One Headlight” and Keb’ Mo’s bluesy “Every Morning.” Vocal selections that tortured lesser speakerseliciting nasal honks, chesty sounds, and the occasional metallic raspdidn’t seem to tax the AWM70 in the least. On several tracks, my notes bore perhaps the ultimate compliment: “Doesn’t sound like an in-wall!”

The AWM70’s overall sonic success wasn’t due just to its refusal to commit the customary sins of the in-wall breed: It seemed to take “active” steps to get things right, in the way that the better floor-standing speakers get them right, most noticeably the way it handled dynamic contrasts. Big, driving rock numbers by Led Zeppelin and John Hiatt pounded and swelled into convincing roars, and Marc-Andre Hamelin’s big Steinway positively erupted in the demonic and magnificently recorded “Grande Sonate” by Alkan. A bravura composer somewhat along the lines of Liszt, Alkan calls for almost humanly unplayable torrents of notes: In several passages it actually sounds as if several pianists are playing the same piano at the same time. The sheer density, rapidity and dynamic surge of the passage (subtitled “Vingt ans”) is nearly as hard on loudspeakers as it is on pianists: I don’t know of any other pianist who can keep up with Hamelin, and I don’t know of any other in-wall speaker that can keep up with the AWM70 keeping up with Hamelin.

On only two of the dozen test tracks did the speaker falter ever so slightly: the Scarlatti piano sonata, where the quiet, “black” spaces between notes weren’t as deep as with the reference Genelec studio monitors, leading to the impression that the individual notes themselves were somewhat less vividly articulated than they could have been; and on the Jennifer Warnes pop vocal track, where just the barest trace of sibilant emphasis added a hi-fi-ish coloration.

To be fair, these are quibbles, not indictments, and blame for the piano effect can probably be pinned not on the speaker itself but to the way gypsum-board and wood-stud wall cavities typically add a resonant smear to the sound by storing and releasing acoustic energy over time. On track after track, the AWM70 handily sailed past the competition, ending up as the most satisfying performer of this installment.

The test data confirmed the AWM70’s basic tonal neutrality, with an on-axis frequency response that, with one-third octave smoothing [not shown], fits an impressive +/- 3dB window from 150Hz to 7.6kHz. Importantly, the off-axis behavior is similarly well controlled, as shown on the graph as a blue trace representing the average of measurements taken at various angles. This on- and off-axis smoothness would suggest that the speaker is likely to sound quite good in a wide variety of real-world acoustical environments, including those in which the speakers are not aimed directly at the listeners. Low frequency extension was very good as well, just missing the manufacturer’s 38Hz spec with the actual measurement coming in at about 46Hz.

Taking all 25 speakers in three installments into account, the AWM70’s most direct head-to-head competitor would clearly be the similarly-expensive Triad InWall Gold Satellite/PowerSub combination reviewed in Part 2. If you’re shopping for the state-of-the-art in in-wall speakers, or simply want to know how competitive the best in-walls have become with conventional box-type speakers, the B&W AWM70 demand and deserves to be at the very top of your must-hear list.

Linn Sekrit 

Like the B&W AWM70, the Linn Sekrit is an ambitious, actively bi-amplified design from an established, high-quality, UK-based specialty audio manufacturer with a loyal international following. Linn sent along two of their LK100 stereo power amplifiers, one fitted with Sekrit-specific tailoring to drive the woofers, and the other tailored to drive the tweeters. Linn claims performance of +/- 3dB from 50Hz to 20kHz for the active version I tested (a passive version is also available at lower cost). With their elegant proportions and slightly bowed grilles, the Sekrits proved to be the most appealing entry in the entire three-part, 25-speaker survey. My German-born wife took one look at the living room wall lined with speakers, pointed to the Sekrits, and said, “Those must be European; I like zem already!”

The design and finish are indeed to a very high standard, although it should be acknowledged that it took a little more time to get the Sekrits installed than the other models in this installment. (We had to dispense with the top layer of gypsum wallboard for the speaker to seat into its bracket. You’ll need longer hex-head screws than those supplied if you plan to use more than the standard single layer of ½ or 5/8 inch wallboard.)

The aural effect produced by the Sekrit was not quite up to the high visual standard set, falling somewhere in the middle of the second tier of performers. The sound was decidedly darker than that produced by the competition, an effect that was unmistakable from the very first tracks. On the Wallflowers’ tune, the bass came across as slightly bloated, putting it out of balance with the guitars and vocals. On the Alkan sonata, I noted that it was “as if someone had stuck a big, thick shag rug under the piano and filled the concert hall with sofas”: Individual notes didn’t ring and “coruscate” like the real thing. On the John Hiatt number, the vocal took a back seat to the bass guitar, an effect also encountered with the Keb’ Mo selection where the guitar seemed too fat and slow to successfully play off the vocal line.

It should be admitted here that there were a few cases in which the Sekrit’s overtly rich tonal presentation actually flattered the music: in the Allegri “Miserere,” where the recording itself can otherwise seem a tiny bit too forward; in the Albinoni “Adagio,” where Gary Karr’s big, nearly four-hundred year old Amati contrabass acquired a solid-as-granite authority unmatched by any other in-wall; and in Jennifer Warnes’ pop tune “The Hunter,” in which the vocal took on an attractively golden honeyed smoothness, making the other speakers sound raspy by comparison.

In general, the softer the playback, the better the Sekrit fared. I suspect this was due to the speaker’s inherent bass-lift functioning as a built-in “loudness contour.” (Found on many receivers, the loudness contour button increases bass at low volume levels to offset the ear’s natural insensitivity to low frequencies at low volumessomething referred to in psychoacoustics circles as the Fletcher-Munson or Robinson-Dadson effect.)

The listening test conclusions were subsequently confirmed by plotting and analyzing the on- and off-axis frequency responses, both of which disclosed an unambiguous bass bulge of about 8 decibels above the Sekrit’s average midrange and treble levels. It would be interesting to know whether this anomaly appears in the passive version as well; it’s possible that the Sekrit’s tonal balance is the product of deliberate engineering, and also possible, though probably unlikely, that the gain structures of the LK100 amplifiers were miscalibrated at the factory. (I say “unlikely” because simply lowering the woofer amplifier’s output by 6 or 8 dB, enough to solve the bulge, would create a wide and fairly deep hole smack in the middle of the midrange, i.e., from about 350Hz to 3kHzwhich would almost certainly produce unrealistic and unappealling tonal balances on almost all musical instruments and voices.)

If your listening tastes favor low volumes and a sound balanced toward the rich side of perfectly neutral, the Linn could be a sterling choice; if you want less tailoring and “editorializing” from your speakers, you’ll probably be better served with a speaker with less “personality.”

M&K SW-95 
An innovator of long standing in the satellite-subwoofer category, M&K recently launched the SW-95 in-wall speaker to compete head-to-head with sat-sub systems in the same price range. The traditional formulatwo-way design with a 5-inch midrange/woofer and 1-inch tweeter on a baffle that uses the wall cavity as its acoustic enclosureis retained and enhanced here by a robust crossover; a rattle-free, magnetically-affixed grille; a ring of dense, pre-cut and pre-scored open-cell foam absorbent to be inserted into the wall cavity to acoustically surround the backside of the baffle; and similar absorbent with peel-and-stick adhesive to be installed directly behind the woofer on the internal side of the opposing wallboard to prevent the woofer’s back wave from reflecting off the wall and traveling back through the woofer itself and into the room. (Slightly delayed in time, such reflections would otherwise combine with the woofer’s forward-radiated output to cause comb-filter type tonal aberrations.)

Inspiring confidence right out of the box, the SW-95 installed easily and achieved a good seal without fuss. The speaker wires were connected to the terminals in the “Normal” configuration, which is said to produce “the flattest overall frequency response.” (Other hookup options include a bass-enhanced mode termed “Equalized,” which is said to be “optimized for playback at moderate and background music levels.”)

On audition the M&K projected a clean, well focused and somewhat forward tonal balance that earned favorable comments regarding articulation of individual instruments and voices in passages that stayed submerged in mud on other speakers. This knack for delineating separate musical strands out of washes of sound was especially striking on the classical “Danza Alta,” the Albinoni “Adagio” and the Jennifer Warnes and Janis Ian pop tunes. There was a realistic sense of projection on the a capella“Miserere” and a crisp, rhythmic propulsiveness to Led Zeppelin’s “Ramble On” that would have driven me into bouts of air guitar-playing had I not taken so seriously the weighty task of sober aural analysis. Evident on all selections was the SW-95’s freedom from that characteristically thick, smudgy character in the lower midrange that often mars even the best of the in-wall breed.

Perhaps inevitably, though, the highlighting and clarifying of inner detail had a bit of a dark side, heard in this case as a slight but unmistakable bleaching or “leaning out” of harmonic richness. The piano sounds on both the Scarlatti and Alkan sonata tracks showed good piano “bite” but were missing some “body,” the sense that the sound was emanating from an instrument the size and weight of a real piano. Similarly, Janis Ian’s voice on “Breaking Silence” was not as fleshed out and therefore not as believable as with the very top rank of performers. And John Hiatt’s voice lacked the requisite fullness and therefore conviction on the M&Ks: When he sneered, “Don’t you know you’re riding with the King,” I thought the better phraseology would have been, “Would you believe you’re riding with a Duke?”

Though noticeable, these timbral effects were generally quite slight and, with the exception of the Hiatt tune, did not generally diminish my musical satisfaction; clearly, the SW-95 belonged in the top 4 or 5 in the field of 25 in-walls I’ve tested to date in this series.

The M&K’s measured response confirmed what I heard in the listening sessions, to wit, an admirably clean, smooth response throughout its range, with a gentle and modest (approximately 2 dB) droop from the midrange down to the upper bass. The off-axis behavior is perhaps the smoothest and flattest in the entire survey, suggesting that the SW-95 may very well be the very best choice in installations where the speakers must be sited well above or off to the side of the general listening area. The speaker’s documentation did not include a sensitivity rating; 91 dB/1 watt/1 meter would seem warranted in the “Normal” hookup mode that I used throughout the tests.

Considered as a full-range speaker, the SW-95 has impressive strengths, missing the top rung only because of a slightly treble-skewed tonal balance. More than perhaps any speaker in the full three-part survey, the SW-95 needsand, tellingly, deservesto be partnered with a good subwoofer. And there’s probably no better maker than M&K to fill exactly that void; I suspect that the combination would challenge the Triad InWall Gold system and perhaps even surpass the B&W AWM70.

Triad OmniPlus 
I was eager to audition Triad’s new Omni Plus in this round of testing, as its big brother, the InWall Gold System, consisting of a pair of in-wall speakers with matching in-wall subwoofers, came away with Top Dog billing among all 20 flagship in-walls I’d tested in the previous installments.

Like the InWall Gold (and all Triad in-walls for that matter) the OmniPlus has a lot in common with a conventional in-room speaker, including the fact that it is supplied with its own enclosure. From the engineering perspective, this allows Triad’s design team to optimize the woofer’s response for a known enclosure volume, as opposed to the conventional arrangement, in which the speaker is simply stuffed in a hole in a wall of unknown size and construction particulars. In Triad’s design, not only can the woofer’s response be predetermined and massaged by the engineer in advance of installation, but by not utilizing the walls themselves as the enclosure, the Triad approach significantly reduces the sonic mud that typical walls cause by vibrating more or less sympathetically with the woofer.

Like the InWall Gold, the OmniPlus is a two-way, nominally full-range design. I had my helper, Brandon Danieli, install the OmniPlus in its test wall as a retrofit rather than as new construction, as I wanted to see if the extra bulk of the speaker’s enclosure would present an added complexity to consumers with existing construction. It didn’t; installation went without a hitch.

A triumph of value engineering, the OmniPlus was edged out in this installment only by the more electronically ambitious, and significantly more expensive, B&W AWM70. It was the M&K SW-95 and the B&W Signature 7—the speaker that topped the list of conventional (unenclosed) speakers in the previous surveys—that proved to be the OmniPlus’s main competition for top honors in its price range. The Triad and the Signature 7 have a lot in common: Both display refreshingly natural, neutral tonal balances, relatively free of idiosyncratic “flavorings,” e.g., boomy, or honky or tizzy colorations that they freight on the music passing through them.

My listening session notes for the OmniPlus enthuse about best-of-class clarity, focus, dynamics, and even bass performance. Recorded in an old French monastery, the 10 voices in the Allegri “Miserere” had a haunting, and entirely appropriate, floating-in-space quality that even the B&W AWM70 couldn’t quite match. Cecilia Bartoli’s rich mezzo-soprano integrated flawlessly with her piano accompaniment on the Scarlatti “Gia il sole del Gange”canzone. The speaker kept its grip on the demanding Alkan piece, preserving a realistic piano sound no matter how maniacally it seemed Marc-Andre Hamelin ripped up and down the keyboard.

But it wasn’t only the classical genre where the OmniPlus satisfied. The Wallflowers rocker quickly turned into an exercise in grinning and foot-tapping more than dispassionate note-taking, and the bluesy Keb Mo number positively radiated front-porch authenticity. The Janis Ian song was tight and sassy, sounding more like a good floorstanding speaker than like a relatively affordable in-wall. Perhaps even more than the Signature 7, the OmniPlus sounded convincing enough to make me want to turn it up, something which increased the listening pleasure—even magic—albeit only up to a point. That point, as it turned out, was 95 decibels, beyond which the OmniPlus took on a progressively hard, shouty character, although it should be admitted that this occurred with allthe speakers at about this level or even lower—all, that is, except the AWM70, which was good for another 2-3 dB before the same effects set in.

The success of the subjective testing was duplicated in the objective analysis which followed a few days later, disclosing for the benefit of the eyes what the ears had already sorted out: a textbook-right frequency response through the all-important midrange. From about 78Hz to a little over 1kHz, a space of four of our hearing system’s ten-octave range, the on-axis response fits within an extraordinary +/- 1.5dB window—this without the benefit of any statistical smoothing. (Adding one-third octave smoothing, something rather akin to what our hearing system does naturally, lets the curve fit within an almost unheard-of +/- 1.3dB window.)

Likewise, the off-axis average shows exemplary control, confirming that the speaker ought to be considered a leading candidate for installations necessitating placement in less-than-ideal locations relative to the main listening area. Priced at a fraction of B&W’s stunning new AWM70, and Triad’s own equally stunning InWall Gold system, which has defined the performance possibilities for the whole in-wall genre for several years now, the OmniPlus has quietly emerged as the odds-on favorite for those who care deeply about music but don’t want to spend thousands on in-wall speakers that do it justice.

Vandersteen VSM-1
For the past 20 years or so the Vandersteen name has been familiar to music lovers and audio enthusiasts around the world, for whom the Model 2 series of floorstanding speakers has been an enduring icon of high-performance and sheer bang-for-buck value. I was keen to include the Vandersteen VSM-1 speaker in this survey because of my own positive experiences with the Vandersteen 2 series through the years, and the obvious esteem the nameplate enjoys, but also because, unlike all other speakers in the survey, the VSM-1 is not an in-wall but an on-wall design. (It was Richard Vandersteen who quipped that he’d start producing in-wall speakers “when Steinway starts making in-wall pianos.”) Just five inches deep and a foot wide, the VSM-1 is based on a 6-1/2″ woofer and 1″ tweeter.

The enclosure hangs on the wall by way of a sturdy steel clip on the back side that slots into its mate that is attached to the wall by molly-type bolts. The whole affair has the advantage of being rock-solid and also removable: Lifting up the 31-lb. speaker “undocks” it without involving so much as a single tool or speck of sheetrock dust.

Despite its moderate 86 dB/1 watt/1 meter sensitivity rating, the VSM-1 needed to be turned up rather higher than the others in this installment to generate an equivalent sound level; clearly this is not a speaker that will rock `n roll on 20 or 30 watts; if you intend to use the VSM-1 for foreground music, you would do well to look toward the higher end of the manufacturer’s recommended 30-to-100 watts of amplifier power.

With the output levels carefully matched by adjusting the digital volume control on the preamp, I settled in for several extended listening sessions. As with all the speakers, I led off with the Jennifer Warnes vocal track, which came across cleanly and convincingly, albeit with a little extra boost in the sibilance region. (Sibilants are the noise-like “s” and “sh” sounds, typically characterized by strong output in the broad 2-6 kHz part of the spectrum.) Next, the percussion strokes on the “Danza Alta” were rather better defined than on the competition, the whole lilting number being brought off tidily and successfully.

Bartoli’s Scarlatti canzone and Pogorelich’s piano sonata from the same composer likewise earned high marks. So far, the speaker was meeting its audiophile pedigree. The VSM-1 did not fare quite as well on the pop tracks that followed. The Carver amplifier’s LEDs flashed “clipping” before the John Hiatt number got up enough steam to rock wholeheartedly, an effect that was also limited the success of the Janis Ian, Wallflowers and Led Zeppelin tracks.

On all these pop tracks, as well as the classical “Grande Sonate” by Alkan, the sound was noticeably compressed dynamically at all levels above about 90 decibels. Whether this was due to the 65-watt per channel Carver amp running out of steam prior to clipping, or the natural reluctance of the Vandersteens to track musical dynamics remains a bit of a mystery.

Like a lot of audiophile speakers, the Vandersteen VSM-1 sounded rather better than it measured, requiring a +/- 5dB window to accommodate its response from about 85Hz to 12kHz. Within that range the VSM-1 had notable peaks centered at about 550Hz, 1.5kHz and 4kHz, which appear in both the on-axis and off-axis curves.

The shape of these peaks, and their location on the frequency axis, reminded me of the KEF CR200Qr speaker reviewed in the February 1996 installment and the Canton InWall 9 reviewed the following month. Both the KEF and Canton were disappointing performers united in their use of a coaxial design, that is, the tweeters was nested in the center of the woofer. I wondered whether the Vandersteen might have employed the same physical arrangement. A careful reading of the literature disclosed that, indeed, the tweeter is mounted coaxially with the woofer. As with the KEF and Canton, I suspect that the rather anomalous response curves are the product of interference patterns between the wave energies radiated by the tweeter and the woofer cone that surrounds it.

The VSM-1’s rating of 86dB with a 1 watt input, measured at 1 meter, would appear to be very close to the actual test result I got, which was in the 85-86dB range.

Though it misses the very top rank in terms of pure musical authenticity, the Vandersteen nevertheless made a positive overall aural impression and simultaneously supplied an interesting architectural counterpoint to the conventional, “same old, same old” in-wall genre.

And, despite the measured similarities, it certainlysounded a lot better than the coaxial designs tested in previous installments. If you can give it 80 to 100 watts of clean amplifier power; listen at low to moderate levels; like the slightly forward tonal balance; and take comfort in the notion that you could take the speaker with you without having to patch a big hole in the wall, the VSM-1 will prove to be an intriguing possibility.

Sidebar: Test Setup

Each speaker was mounted in a four-foot high wall formed of two-by-four wood studs set 16 inches on center, and sheathed with a single layer of half-inch gypsum board on the back side and two layers on the front. The two front layers were separated by a paper-thin, sticky constrained-layer damping sheet (Omni-brand dB-Rock) to control drum-like wall resonances. The 2,436 cubic inch cavity-a volume typical in residential wall construction with requisite fire-blocking-was filled with conventional R-11 fiberglass insulation.

Each speaker was installed by Patrick Calderone, a professional A/V installer based in Northern California, per manufacturer instructions. All speakers were checked for good “seating” in the wall, as well as for buzzes, rattles and air leaks. Both gypsum board layers and contrained-layer damping sheet were changed whenever the cut-out requirements for a speaker did not closely match the hole left by the preceding speaker tested.

To get the most accurate ground-plane measurements possible, each speaker/wall system under test was set flush into the ground, speaker aiming skyward, in a quiet, rural setting-my
backyard.The joints between the ground and wall edges were filled and smoothed to essentially eliminate secondary radiation. If the speaker had a level control it was set to the “flat” or “0” position. If, as in several cases, the speaker’s tweeter was pivotable, it was aimed straight ahead and left there.

An ACO Pacific instrumention microphone and a Techron TEF20HI connected to a PC were used to generate, capture and display test signals. The test signals were amplified by a Soundstream DA-2 power amplifier set to deliver 1 watt at 8 ohms (2.83 volts) and then routed to the speaker under test via 12-gauge low-oxygen speaker cable. Each speaker was tested with the microphone at 2 meters away directly on-axis, as well as at 30 and 60 degrees off-axis laterally, and at 30 and 60 degrees up and 30 and 60 degrees down. Lateral responses for those speakers with non-vertically aligned drivers were taken at 30 and 60 degrees both to the left and to the right. Six decibels were added to the curves to show the plots as if they were derived at 1 watt/1 meter.

I exported the on-axis and off-axis response files to WaveMetrics’ Igor Pro scientific analysis and graphing program, where I averaged all eight off-axis curves for each speaker at each of 4,096 data point to provide a composite picture of how the speaker distributed its energy into the environment. (This is a critical element of the sound of in-wall speakers in particular, due to the fact that off-axis energy predominates the sonic presentation in most casual residential environments.)

Prior to taking frequency response measurements, an energy-time curve (ETC) test was run for each speaker to verify the accuracy of the test setup. Reflections off structures, etc. received within the 58 millisecond measuring time window were never higher in level than -40dB, and typically registered about -60dB out to 120 milliseconds, enabling an extraordinary level of performance detail to be captured, stored and analyzed.

I’d like to thank the following individuals for their help in establishing what amounts to the most rigorous regimen ever used for comparative testing of in-wall speakers: Dr. Floyd Toole, director of research at Harman International; Don Keele, technical editor of Audio magazine; and Farrel Becker of Techron, Inc.

SIDEBAR: Software Used

The following compact discs were used in the core listening portion of the tests:

Francisco de la Torre: “Danza Alta” from El Cancionero de Palacio: 1474-1516, performed by Hesperion XX, Jordi Savall, director. Astrée.

Alessandro Scarlatti: “Già il sole dal Gange” from If You Love Me: 18th Century Italian Songs, performed by Cecilia Bartoli, mezzo-soprano, and György Fischer, piano. London.

Domenico Scarlatti: “Sonata K.20 in E major,” Ivo Pogorelich, piano. Deutsche Grammophon.

Mary Black: “Still Believing” from Babes in the Woods. Gifthorse/Curb.

John Hiatt: “Riding with the King” from Riding with the King. Geffen.

Sting: “Mad About You” from The Soul Cages. A&M.

Sergei Prokofiev: Introduction to “Romeo and Juliet, op. 64,” Kirov Orchestra, Leningrad, Valery Gergiev, conductor. Philips.

Counting Crows: “Mr. Jones” from August and Everything After. Geffen.

Chris Rea: “Auberge” from Auberge. Atco.

Federico Torroba: “Castles of Spain” from A Tribute to Segovia, Christopher Parkening, guitar. EMI Classics.

The author owns Keith Yates Design Group, a California-based consulting firm providing architects, builders and owners with design, engineering and testing services for residential entertainment venues nationwide.