To anyone but an expert, Sonance’s S625T is visually indistinguishable from thousands of generic in-wall speakers—some of which cost as little as $100 a pair, a pittance next to the $1,000 that a pair of S625Ts will cost you. And the S625T sports the same white metal grille, white plastic bezel, and two-way (woofer/ tweeter) design as a generic in-wall.

Why might one in-wall be worth $1,000 when a seemingly identical one is worth only $100? It all comes down to the parts, which were Sonance’s focus when it created the S625T. The S625T represents the zenith of Sonance’s extensive revamp of the Symphony line. (That’s zenith as in “maximum height,” not as in the storied but practically extinct TV brand.) The idea was to take the ordinary in-wall as far as it could go. The logical question, though, is how much sense it makes to take the ordinary in-wall to such heights.

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Like most conventional, two-way in-wall speakers, the S625T features a pivoting tweeter that lets your installer direct the sound somewhat, and a switch that boosts or attenuates the sound coming from the tweeter by 3 decibels. (Click image to enlarge)

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The speaker sports a woofer cone and a tweeter dome made from beryllium, an extraordinarily stiff yet incredibly light metal. The benefit to the listener is lower distortion and a more extended, lifelike treble. Unfortunately, beryllium is extremely brittle; many of the cones and domes break during production. Also, its toxicity complicates the manufacturing process. Thus, you won’t often hear the word beryllium tossed around at Circuit City.  The metal has been used almost exclusively in such superspeakers as JMlab’s Grand Utopia Be. These speakers cost tens of thousands of dollars per pair, which is why I was shocked to learn that Sonance had incorporated beryllium into a $1,000-per-pair in-wall.

I recently got a chance to divine the benefits of beryllium during a visit to a different speaker manufacturer (which I cannot name because I was sworn to secrecy). There I heard a prototype of a new flagship speaker bedecked with six beryllium-coned midrange/woofer drivers. The new model sounded both more delicate and more dynamic than the company’s aluminum-coned speakers; its midrange was stunningly natural and clear.

Sonance made one more major renovation in the S625T: a front baffle made from three-quarter-inch medium-density fiberboard (MDF). MDF is the same material that forms the cabinet of most good speakers; its damped character minimizes resonances that can mar the sound of a speaker. Its weight also helps subdue wall vibrations, which themselves can color the sound. In contrast, generic in-walls employ molded plastic baffles that vibrate like the handlebar of a Harley-Davidson Sportster.

The S625T packs a few other improvements, but its configuration is fairly standard. Like most in-walls, it has a pivoting tweeter to help aim the sound, and a treble switch with Normal, Boost, and Cut settings. One seemingly mundane feature works to the speaker’s credit: its simple, four-screw mounting system. All it takes to mount the S625T is 30 seconds with a RotoZip and four taps of a powered screwdriver’s trigger (plus, of course, the time it takes to run the wire).Even when reproducing the particularly raspy vocals on singer/songwriter Ron Sexsmith’s eponymous debut CD, the S625T’s beryllium woofer maintains its composure beautifully; Sexsmith’s voice retains its rough quality, yet never sounds grating or edgy. Many speakers sound awful with this recording—that’s why I like to play it, and the S625T is one of the few speakers I have heard that reproduces it well. Similar results obtain when I play other vocalists, dialogue-heavy movie soundtracks, and saxophone recordings; the midrange of this speaker is absolutely excellent.

Apparently, beryllium also works well in the high frequencies. The S625T’s treble exhibits a nearly perfect balance; no matter what program material I choose, it never sounds hissy or edgy, but never sounds dull, either. To my surprise, the tweeter’s excellence does not enhance depth or ambience; I hear the rather dimensionless sound typical of in-walls. But for the S625T’s natural tonality, I’ll forgive.

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What makes this seemingly ordinary in-wall special? A woofer and tweeter made with beryllium diaphragms. Beryllium is a light, stiff metal normally used only in extremely expensive speakers. (Click image to enlarge)

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Despite its relatively small woofer, the speaker does not choke on the brutally deep bass in singer Holly Cole’s version of the Tom Waits classic “Train Song.” However, this is where the wisdom of putting so much money into a small in-wall comes into question. As with other conventional in-wall speakers, the wall vibrates along with the bass, muddying the sound. Unlike larger, heavier in-walls, the S625T is not massive enough to keep the wall vibrations under control.

Sonance has an elegant solution—an optional back box for the S625T that separates the speaker from the wall cavity and cleans up the bass. However, if you choose this option, it will diminish the speaker’s bass response and you will probably want to add a subwoofer. If you want big bass without a sub, your installer can simply glue small pieces of two-by-four into the wall to stiffen it.

Either way, make sure your installer does not simply slap a pair of S625Ts into your wall and call it a day. It deserves careful installation and fine-tuning—and that’s not a statement I would make about any other conventional two-way in-wall speaker.

DESCRIPTION
In-wall speaker with optional back box. Round in-ceiling version (S625RT) also available. Subwoofer optional

COMPONENTS
6.5-inch beryllium-cone woofer, 1-inch beryllium-dome tweeter

CONNECTORS
Spring-loaded binding posts for speaker cables; accepts bare wire or pins

DIMENSIONS
12.2 x 8.3 inches (hw); 3.3-inch installed depth

PRICE/CONTACT
PRICE: $1,000/pair
CONTACT: 800.582.0771, www.sonance.com