Voxativ Ampeggio loudspeaker Page 2
"I wasn't interested in making cabinets," Inès Adler says, "but when drivers get better, the idea comes over you: Maybe I can do more. . ."
Thus did the Ampeggio come about: a twice-folded horn, nearly 9' from throat to mouth, that's intended to amplify the driver's rear waveand because all such horns act as acoustical low-pass filters, the real objective is to maximize in-room bass extension. The Voxativ driver's high excursion was one boon to the design effort; another was an unexpected source of engineering inspiration: "I had the idea to optimize [the canine's] radiation resistance," Adler says, "and I thought of the Lockheed 'Stealth' fighter plane, which has no real curves. Its surfaces are all faceted." Realizing that she couldn't control the reflection of the soundwaves within a circular path, Adler went the other route and created the bends in the Ampeggio horn with a series of "facet boards," the sizes of which increase as the sound travels from throat to mouth. The narrowest of those boards (about 2") are used to create the tight curve of the horn's first fold, with wider boards comprising the second bend, near the top of the cabinet, and the widest used to form the comparatively large-radius curve just behind the horn's mouth (which itself measures about 14" square).
While developing the Ampeggio, Adler decided to approach some piano companies for help in transforming into reality the now-complex cabinet design. "I was disappointed at first," she says, "because all of the [European] companies I asked say their stuff is made in China." But Adler eventually discovered Schimmel, a 125-year-old, family-owned company in Braunschweig that also happens to make the best-selling German piano in America. Schimmel's engineers were intrigued by the project and made some contributions of their ownincluding the advice that, because any music-making device oscillates, it might be best to make a loudspeaker in such a way that its oscillations can be predicted and controlled, rather than try to kill them off altogether. Consequently, the Ampeggio's cabinet is made from a variety of woods from Schimmel's own selection: The side panels are made of the same three-layer sandwich used to make piano lids, medium-hard particleboards form the inner surfaces, and carefully aged tonewoods are used for the baffle and the surfaces immediately behind the driver.
At the end of the development phase, company CEO Hannes Schimmel-Vogel asked Adler to bring her reference audio gear to his piano factory so that he could hear the finished product. After listening to the Ampeggios, Schimmel-Vogel declared that he'd never before heard such realistic sound from a loudspeaker, and asked to be a partner in the venture, rather than merely a behind-the-scenes supplier of cabinetry. Thus the "Voxativ by Schimmel Pianos" logo, made of brass and set into a finish comprising 13 layers of lacquer, plus a protective coat of polymer finish. Just like Schimmel's pianos.
The Ampeggio is 47" tall at its tallest and 19" deep at its deepest: dimensions that aren't too unusual for very good domestic speakers. The small end of the horn terminates at a point approximately 10" above the center of the driver, and while there's a bit of room between the rear portion of the driver and the various wood surfaces, most of the horn's throat is filled with two different kinds of acoustically absorbent material. One such blanket, in fact, covers the rear of the throat and almostbut not quitemakes contact with the rear of the magnet once the driver is tightened into place.
Internal cables comprise four strands each of very stiff, solid-core copper, leading to a pair of binding posts at the bottom of the enclosure. A pair of 10" angled legs that wouldn't look out of place on a Quad ESL support the rear of the Ampeggio cabinet; those are capped off with smooth plastic gliders that, in my home, made it reasonably easy to scoot around the heavy cabinet without shamble-izing the floor. Underneath the cabinet's front edge, threaded inserts accept a pair of adjustable feetwith enough leeway to alter the cabinet's tilt by a degree or twoterminated with hard rubber and slim felt pads. Ball joints allow the feet to tilt easily, and may even contribute a bit of mechanical isolation: a nice touch.
Don't fence me in
Positioning the Ampeggios was a matter of optimizing and balancing three different parameters: bass extension, evenness of bass response, and overall naturalness of treble response. The last was easy, and required little more than making sure the cabinets were angled toward the listening area by just the right amount: too little, and high-frequency response became uneven and "fussy" at the central listening seat; too much, and the highs rolled off prematurely. It also proved a good idea to leave a generous amount of space between me and the speakersnot because the Voxativs were hard to take in any way, but because some space was required for the outputs of driver and horn to jell.
Getting the bass right took some doing. Although the Ampeggios seemed to benefit from some degree of room-boundary bass reinforcementthey did not, for example, sound their best when sited more than 3' from my rear wall, as do Quad ESLs and Wilson Audio Sophiasthey needed more space than I expected. (The Voxativs also sounded best when my listening seat was itself a little farther than usual from the wall behind it.) More critically, the Ampeggios' response evenness in the mid- and upper-bass regions suffered when the cabinets were brought too close to their respective sidewalls: another surprise. (Granted, I'm spoiled from years of living with Quad electrostats and Audio Note AN-Es, neither of which at all mind being close to the sidewalls.)
But after a bit of work, the Voxativ Ampeggios sounded superb in my 12' by 19' listening room when placed approximately 24" from their respective sidewalls, 29" from the wall behind them, and toed-in toward the listening position by about 10°. Speaking of which, I found that slightly more toe-in was needed when using the Voxativs in my home's largest room, which measures 27' by 23'. (This room is slightly irregular in shape, opening as it does to the kitchen, a hall, and a sort of office nook; consequently, these dimensions are approximate.) In that installation I had the speakers positioned in front of the short wall, straddling the hearth and firing across the room's (slightly) longer dimension. (I didn't try the other way around, which would have required a near-catastrophic furniture rearrangement.) Most of my listening was done in my smaller room, which forms the basis for all of the comments that follow, but bear in mind that the Ampeggios sounded even better in the larger room, especially throughout the upper-bass region.