Direct Acoustics Silent Speaker II
Its seemingly paradoxical name refers not to any inability of the Silent to create sound, but rather is intended by its maker to indicate two aspects of its performance. First is the ability of the loudspeaker boxes to "disappear" in the sense of not being readily apparent as sound sources. Well, okay, everyone wants that. The other intended sense of Silent is that the woofer and its loading arrangement were designed to minimize stray noises created by the woofer's excursion, or by the movements of air within, or in and out of, its vent or port.
Direct Acoustics, founded in 1995, is the brainchild of Winslow Burhoe, an important figure in the history of modern loudspeaker design. In 1960, Burhoe had been studying pipe organ at the New England Conservatory when he was chosen for an internship at Acoustic Research, and the direction of his life was set. He assisted Edgar Villchur on the design of the AR4. He went on to found EPI/Epicure loudspeakers (later acquired by Harman International), Burhoe Acoustics, and Direct Acoustics. (He influenced designs from KLH, Snell, Boston Acoustics, Audio Products International (aka API, and for whom he reworked a late prototype of the Energy 22), and others.
The Silent Speaker II is a wide, rectangular box whose top panel is raked at an angle of about 22°: the enclosure is about 22" tall at the front, 25" tall at the rear, 13.5" wide, and 9" deep. The top panel holds a 6.5" woofer and a 1" soft-dome tweeter. Each speaker weighs about 25 lbs. A recess in the upper part of the rear panel holds one pair of binding posts with red and black plastic hex nuts. The pairs are mirror-imaged; I positioned them with the tweeters to the inside. A port about 1" tall runs nearly the full width of the bottom of the front panel. The speakers come with grilles of stretched black fabric that are secured to the top panel with squares of adhesive foam. The edges of the enclosure are rounded, with a round, compliant foot about 1/4" thick at each corner.
The Silent Speaker II is available in one finish: black ash veneer. Its monolithic look isn't really contemporary, but the design brief doesn't appear to have been "Sound okay and win beauty contests." Compared to recent offerings from any number of companiessuch as PSB, whose curved enclosures are elegantly veneered and stainedthe Silent looks a bit dated, even DIY. But I don't think that that will matter to the right customers, who will ignore the styling and the somewhat handmade look of the woofer cones, and enjoy a much wider frequency extension than is offered by any other basically listenable loudspeaker at or near its price.
Direct Acoustics claims for the Silent Speaker II frequency responses of 40Hz10kHz, ±2dB; 30Hz17kHz, ±4dB; and 20Hz20kHz, ±6dB (!). No sensitivity is specified. Also stated are impedances of 6 ohms average and 4 ohms minimum.
Visually and, to an extent, through its acoustical approach, the Silent Speaker II calls to mind three venerable speakers from what I term a Golden Age of Audio (1970s1980s): Stig Carlsson's Sonab omnidirectional, Shahinian Acoustics' Arc polyradial, and the Epicure Model 20. All are rather squat floorstanders that fire as much toward the ceiling as toward the front, but after that the similarities taper off.
The Sonab had four leaf tweeters arranged in a square pointing up at about 45° from the top of a rectangular woofer enclosure. I heard a pair ca 1976 and was thoroughly gobsmackedtheir sound was so much more dimensional, vivid, and tactile than from the Klipschorns the dealer had in the same room. (Of course, it's possible that the dealer had intentionally set up the K-horns poorly.)
Shahinian's Arc, still in production at $5500/pair, looks quite similar to the Silent Speaker II, except that it's much more complicated. The Arc is a three-way design with the woofer, midrange, and tweeter all on the canted top panel, and a passive bass radiator on the rear, at the end of a transmission line. I heard the Arcs more than a decade ago, when I was writing for The Abso!ute Sound, and was very impressed by their natural timbre, superwide soundstaging, and their bass and dynamicswhen driven by an amplifier with adequate current and damping factor.
Epicure's Model 20, of course, is a direct ancestor of the Silent Speaker II, with a nearly identical cabinet shape. (If I ever heard the Model 20, I don't recall it, but I certainly recall the post-Burhoe EPI 3.0the first great loudspeaker I heard that was tantalizingly just beyond my financial reach.) Epicure's "secret sauce" was to create different loudspeakers out of combinations of a basic module Burhoe designed, which consisted of one 8" woofer and one 1" tweeter and the necessary crossover components. The Model 20 had comprised two of these modules, and therefore was somewhat bulkier than the Silent Speaker II.
In conversations, Burhoe told me that his design goals for the Silent Speaker II were: as extended and even a frequency response as possible; wide dispersion; a vent designed to be free of noise and resonances; and the prevention of standing waves inside the enclosure. It was for the sake of wider dispersion that he went from his previous 8" woofer designs to a 6.5" woofer. The woofer loading is designed somewhat in the manner of horn loading, and that apparently is where Burhoe concentrated much of his development work. I surmise that the cabinet's interior is more complicated than in other speakers costing under $1000/pair, not only from the remarkable bass performance but also because the recess for the binding posts is more than halfway up the rear panel instead of at the lower edge, where you might expect it. The latter suggests to me that there is an internal structure, whether braces or a waveguide, that requires that placement.