|
Canton Karat 300 Bookshelf speakersThe Canton Karat 300 is a three-way bookshelf system whose 10-inch long-throw woofer crosses over to a 1-1/2-inch dome midrange driver at 800 Hz. At 4,000 Hz there is a second crossover, to a 1-inch dome tweeter. The sealed wooden cabinet is available in walnut, black, or white, and the removable perforated-metal grille is finished to match the cabinet. There are no user-adjustable controls, and the heavy-duty plastic spring-loaded connectors are recessed flush with the rear of the cabinet. The Karat 300 has a rated sensitivity of 89 dB sound-pressure level (SPL) at 1 meter with a 1-watt input, and it is recommended for use with amplifiers rated up to 100 watts output in rooms of up to 1,600 cubic feet. The speakers can be installed either vertically or horizontally. The cabinet measures about 19-3/4 inches high, 12-1/4 inches wide, and 11-1/2 inches deep, and each system weighs 33 pounds. Price: $800 per pair. Lab Tests We installed the Canton Karat 300 speakers against a wall on a ledge about 27 inches from the floor, which is essentially the placement recommended in the instruction booklet. In listening tests we preferred the wall placement over free-standing pedestal mounting. The averaged room response from the two speakers was exceptionally uniform, varying only 6 dB overall from 100 to 18,000 Hz. A major room resonance produced a peak at about 60 Hz, but there was less irregularity in the mid and upper bass than we have usually measured in this room. Our close-miked woofer-response measurement yielded a broad maximum output from 70 to 150 Hz. The output fell at 12 dB per octave below 60 Hz and at about 3 dB per octave from 150 to 800 Hz. When this bass curve was spliced to the room-response curve, the overall composite frequency response was within 7 dB from 50 to 20,000 Hz. Quasi-anechoic FFT frequency-response measurements, made on axis at a distance of 1 meter, showed about the same variation from 180 to 23,000 Hz except for a dip between 2,000 and 3,000 Hz that appeared to be a cancellation effect between the two higher-frequency drivers (it did not appear in the room curve or at most angles off the speaker's axis). Response curves made on axis and 45 degrees off axis began to diverge above about 7,000 Hz and more rapidly above 10,000 Hz. This effect suggests that the dispersion of the dome tweeter was not quite as wide as it might have been, possibly because the metal grille interfered more as the off-axis angle increased. The phase linearity of the system was very good, with a group-delay variation of less than ±0.2 millisecond from 2,000 to 20,000 Hz. The impedance of the Karat 300 measured 7.5 ohms in the range from 110 to 170 Hz, confirming its nominal 8-ohm rating. Impedance reached a maximum of 25 Ohms at the 62-Hz bass resonance, measured 20 ohms at about 1,200 Hz, and fell to 7 ohms between 10,000 and 20.000 Hz. The system sensitivity at 1.000 Hz was 88 dB SPL at 1 meter with an input of 2.83 volts. We used a drive level of 3.5 volts, corresponding to our standard 90-dB reference level, for woofer-distortion measurements. The distortion was less than 2 percent from 100 to 40 Hz and only 5.8 percent at 25 Hz. The Karat 300 demonstrated excellent power-handling ability. With single-cycle tone bursts at 100 Hz, the woofer began to distort smoothly at about 400 watts input, but it did not become audibly raspy at the amplifier's maximum output of 1,055 watts into the speaker's 8-ohm impedance. We used 1,000-Hz tone bursts for the midrange test, reaching 660 watts into the 20-ohm speaker impedance without major distortion, though the single-cycle bursts did begin to sound "hard" at that level. Finally, the dome tweeter had no problem reproducing 10,000-Hz tone bursts at the amplifier's maximum of 1,080 watts into 7 ohms. Obviously, the Karat 300 can handle just about all the power anyone is likely to deliver to it without undue audible distortion or physical damage. Comments The sound of the Canton Karat 300 lived up to the promise of its measured performance. Overall, the sound was well balanced, most of the time without audible emphasis of any part of the audible spectrum. Compared with some other speakers, the extended high end of the Karat 300 imparted a sense of greater definition to music, but without any tendency toward overbrightness. The bass sound was surprising, seeming to be much deeper than our measurements indicated. In part this was due to the speaker's strong output in the 100-Hz region, which can suggest a low-bass content that is not really present. However, we also heard (and felt) enough deep bass at various times to confirm that the Karat 300 has a healthy, relatively undistorted output far below its 60-Hz resonance frequency. Encouraged by its showing in our peak-power tests and by the availability of high-powered amplifiers, we drove the Karat 300 to possibly risky output levels, using wide-range CD's as the source. The results were most gratifying-the speakers retained their open, uncompressed sound even under the most extreme conditons. In today's market, the Canton Karat 300 is a moderate-priced speaker, but it delivers much more than moderate performance. ![]() |