关于琴柏音箱的问题（已解答，满意）

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Plateau Camber 3.5 loudspeaker Robert Harley October 1990

Robert Harley reviewed the Camber 3.5ti in October 1990 (VOl.13 No.10): Plateau Camber is a Canadian loudspeaker manufacturer which concentrates on building small, moderately priced systems. The company started as Edon Acoustcis and was the Canadian distributor of Rega products. It began by making loudspeakers under the Rega name but changed to Camber when Rega set up its own North American distribution. Edon then sold the company to stand manufacturer Plateau. Their products range from the $300 model .7t to the $1000, floor-standing 5.0ti. The second-from-the-top-of-the-line 3.5ti reviewed here ($699/pair) is a completely redesigned version of the Camber 3.5 loudspeaker reviewed by JA in Vol.11 No.8. In fact, the 3.5ti is radically different from its predecessor: it uses a different woofer cone, sports a new metal-dome tweeter, has a much simpler network, and incorporates some cabinet refinements. The 3.5ti is an 8", two-way system employing a carbon-doped polypropylene-cone woofer and a 1" metal-dome tweeter in a bass-reflex enclosure. Unusually, the 3.5ti's woofer is handmade by Camber from components sourced from around the world. It features a diecast frame and aluminum-wound voice-coil. The tweeter is a fluid-damped metal dome made by SEAS. A 2½"-diameter reflex port is mounted below the woofer. The port, woofer, and tweeter are located asymmetrically in the enclosure to disperse cabinet diffraction effects. The mirror-imaged pair is said to sound best with the tweeters toward the outside. Camber has paid significant attention to controlling cabinet resonances in their loudspeakers. The 3.5ti's ¾" particleboard enclosure is made more rigid by two braces just above and below the woofer. The center brace is slightly larger than the interior cabinet dimension, causing the enclosure to bow very slightly in the middle. This technique reportedly reduces panel motion. In addition, acoustic foam has been applied to the inside walls to further damp resonances. The seven-element crossover is a highly damped second-order electrical network, which is said to result in third-order effective acoustical slopes in the 3.5ti. Instead of using an inductor in series with the woofer, a capacitor and resistor are wired in parallel with the woofer. This technique reportedly has the advantages of making the load look more like a pure resistance, and doesn't introduce the ringing associated with an inductor. Crossover frequency is 2.7kHz. Because Camber is a Canadian company, it has ready access to the National Research Council's testing facilities, run by Dr. Floyd Toole (footnote 1). In fact, Camber's factory is only a two-hour drive from the NRC. Although the NRC was used during the 3.5ti's design, Allan Devantier, designer of the Camber line, relied primarily on DRA Lab's MLSSA loudspeaker and acoustic measuring system. In fact, Allan was one of the early designers to use MLSSA, a system now considered indispensable in loudspeaker design and evaluation. The 3.5ti is finished in black ash vinyl veneer (oak vinyl veneer is also available) and covered with a black grille cloth. A single pair of five-way binding posts is mounted at an angle in the terminal cup. Overall, the 3.5tis are well-built and attractive. I would, however, like to have seen a bi-wiring provision.

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Listening
I auditioned the 3.5ti on the Mission stands with which the Mission Cyrus 782 and Fried Q/4 that I also review this month were auditioned. These stands are somewhat low, putting the 3.5ti's tweeter axis 2" above ear level. Camber stands are available for the 3.5ti for $59. While breaking in the 3.5tis with the Dorian Pictures at an Exhibition, a time when I try not to listen to the speakers, I couldn't help noticing the feeling of low-frequency extension from these modest-sized boxes. The 3.5tis have surprising bass extension and a subjective feeling of weight for their size. The low-frequency region was full, robust, and provided a strong musical foundation. Acoustic bass had a warm, rich presentation and conveyed a feeling of the instrument's body. Left-hand lines on the previously mentioned Dick Hyman Plays Fats Waller were more prominent and forward than heard through the Cyrus 782s, with a greater sense of weight. The 3.5tis did a credible job of reproducing the size and power of the organ on Pictures, a remarkable feat for a moderate-sized and -cost loudspeaker. Bass drum had a solid and deep impact, without the thin, wimpy quality often heard from mid-sized loudspeakers. I felt, however, that the bass was a little on the underdamped side, giving a slightly loose and less articulate rendering. Although the 3.5ti's LF presentation had a certain satisfying solidity, it lacked the precision, detail, and transient abilities of the Cyrus 782, an area where that loudspeaker excels. However, the low-frequency region was remarkably uncolored. The sense of pitch in the lower registers was excellent, and there were no glaring resonances that imparted a common character to different recordings. Despite the slightly underdamped rendering, I enjoyed the 3.5ti's bass presentation. The degree of this criticism was minor: I certainly wouldn't characterize the LF performance as tubby or bloated. I felt the bass performance was superior to the Fried Q/4's in pitch definition and freedom from coloration.

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The 3.5ti's overall tonal balance was quite smooth, but with an apparent uptilt in the treble. Throughout the auditioning, I felt that the treble had a hardness that made the upper octaves seem bright. Although there was some excess treble energy, the feeling of brightness was exacerbated by the treble's slightly metallic character. Cymbals had an edginess that brought them forward in the mix and called attention to them. The Böosendorfer's upper registers in the Fats Waller recording took on a slightly brittle sound. The entire treble could be characterized as dry and forward rather than silky-smooth and laid-back. The strings that open the tune "An Hour Away," from Scott Kreitzer's album Kick'n Off, were slightly chalky and bleached. Although the 3.5tis were smoother than many moderately priced loudspeakers, they nevertheless imparted an etched quality to most recordings. Recordings that tended to be overly bright were pushed over the edge of listenability, while many smooth recordings became a little strident. Throughout a large portion of the spectrum, however, the 3.5tis were remarkably smooth and free from coloration. There was a wide "window" from the upper bass to lower treble in which the 3.5tis were open, pure, and uncolored. This is the area of most musical importance, and the 3.5tis did a good job of reproducing natural instrumental timbres through this range, especially instruments without much HF content.

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I experimented with toe-in angle and found the treble was smoother with the loudspeakers pointed straight ahead. This positioning greatly ameliorated the brightness, but at the expense of losing some upper-midrange energy. With the 3.5tis pointed straight ahead, some presence and life was missing from the music. Toed-in toward the listener, the presentation was too bright. I ended up doing most of the auditioning with a slight toe-in, achieving an acceptable balance between treble and midband energy. Incidentally, the 3.5tis were somewhat brighter with the listener's ears directly on the tweeter axis. Remember, the Mission stands placed the 3.5ti's tweeter about 2" above my ears. Stands that avoid placing the tweeters at ear level are therefore recommended. Going back to the 3.5ti's strengths: they presented an excellent sense of space and depth. They could throw a wide soundstage with precise positioning of instrumental images. Vocal and instrumental outlines were focused, stable, and presented with an appropriate sense of image size, although not quite to the degree heard through the Cyrus 782s. Centrally placed instruments and voices were apparently detached from the loudspeakers, and had a feeling of air and space around them. Soundstage depth was similarly impressive, with a distinct impression of distance. Try Reference Recordings' Three-Way Mirror for a convincing feeling of three-dimensionality. Overall, the 3.5ti's resolution of spatial detail was better than the Fried Q/4's. However, the Q/4s had a much sweeter treble that was less fatiguing over long sessions.

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Conclusion
The Camber 3.5ti loudspeaker does many things well at the $700/pair price point, but its musicality is, I feel, somewhat compromised by its treble performance. On the plus side, the 3.5ti has a smooth and relatively uncolored midrange, surprising LF extension, solid bass presentation, and the ability to throw a convincing soundstage. Through the midrange, the 3.5ti presented natural timbres without glare or peakiness. The low-frequency performance, though a little underdamped, was solid, satisfying, and fairly well detailed. The subjective bass extension was deeper than what one would expect from the 3.5ti's cabinet size. The 3.5tis' spatial presentation was excellent, with the ability to throw well-focused images between and behind the loudspeakers, and with correctly sized images. On the down side, I found the treble a little bright, and with hard textures. Either one of these characteristics by themselves may not have been a detraction, but combined, music took on a slightly etched, brittle quality. This was manifested as forward cymbals, steely violins, and an overall dry treble rendering. Positioning the listener off-axis by pointing the 3.5tis straight ahead somewhat ameliorated the brightness, but at the expense of reduced midband energy. My criticisms of the 3.5ti should be put in perspective: it offers excellent performance in many areas, and any speaker is bound to have some deficiencies at the $700/pair price. Depending on where the listener places his sonic priorities, the Camber 3.5ti may be for you. It has a very different sonic signature from the Mission Cyrus 782. Where the latter's lean bass presentation and laid-back perspective may appeal to some listeners, the 3.5ti's warm bass and forward rendering may be better suited to other tastes. I preferred the Cyrus 782's musical interpretation. Despite the criticisms noted, I can nevertheless recommend the Camber 3.5ti. During the auditioning, I enjoyed listening to music through them, the ultimate statement about any product.—Robert Harley