![]() ![]() Our measurements of the horizontal polar response showed little difference between the on-axis and 45-degree off-axis response other than some apparent cancellations in the vicinity of 11,000 Hz. The FFT measurements showed that the group delay of the kg4 was within a 0.8-millisecond range from 3,000 to 20,000 Hz. The Klipsch kg4 had some of the lowest overall bass distortion we have yet measured: 0.2 to 0.4 percent from 100 to 80 Hz, about 2 percent down to 40 Hz, and only 5 percent at 20 Hz. To calculate the distortion we used readings at a driven cone above 60 Hz and the passive-cone readings in the range below that frequency, where its output was dominant. Close-miked readings were taken separately at the driven cones and the passive cone at several frequencies from 100 to 20 Hz. We measured the bass distortion at a constant drive level of 2 volts, the voltage needed to produce a 90-dB SPL at 1,000 Hz. The average impedance over the audio range was from 6 to 7 ohms, making the speaker's nominal 4-ohm rating reasonable as well as consistent with industry practice. The minimum measured impedance of the kg4 was 4 ohms between 150 and 300 Hz, with maximum readings of 25 ohms at 67 Hz and 38 ohms at 2,900 Hz. The kg4 is about 6 dB more sensitive than most speakers of its size that we have tested, which means that it needs only a quarter as much input power to deliver the same sound-pressure level (SPL). The sensitivity of the kg4 measured a high 93 dB when it was driven by 2.83 volts of noise (equivalent to 1 watt into 8 ohms) in an octave band centered at 1,000 Hz. The low-bass output decreased at about 6 dB per octave below 60 Hz (the effective crossover frequency from the driven cones to the passive radiator) and was down only 10 dB at 20 Hz. In general, the output showed a broad maximum between 50 and 400 Hz, and on average it was slightly elevated in the range from 5.000 to 7.000 Hz as well as above 13.000 Hz. There were several minor ripples in the curve between 1,000 and 6,000 Hz, but their peak-to-peak amplitude did not exceed 5 dB. The overall response thus derived was very flat, ☓.5 dB from 30 to 20.000 Hz, making the kg4 rank very high among the speakers we have tested in respect to the range and smoothness of its frequency response. The resulting overall composite frequency-response curve confirmed our earlier subjective impressions, and we consider it to be a reasonably valid description of the performance of this speaker in a listening room of average size and acoustic properties. The bass curve was spliced to the smoothed room-response curve (made with a sweeping warble-tone sine wave), which had been corrected above 10.000 Hz for the known absorption characteristics of the room. For these tests we used close microphone spacing and combined the two curves with allowance for the radiating areas of the different sources. Our FFT quasi-anechoic measurements were made with the speaker standing in the clear, as far as possible from any walls.īass response was measured separately for the driven woofers and the passive cone. The 1-foot distance was used for our room-response measurements. Since no specific suggestions for room placement were supplied with our samples of the Klipsch kg4, we tried them first about 1 foot from the rear wall and moved them through a range sufficient to establish that the speaker-to-wall spacing was not at all critical. There are no external controls or adjustments. The binding-post terminals, recessed into the rear of the cabinet, accept banana plugs, including dual plugs on 3/4-inch centers, as well as wires. On the rear panel of the enclosure is a 12-inch passive cone radiator that extends the low-frequency response limits of the smaller bass drivers. At the top of the panel is a horn-loaded tweeter-a device unusual in home speakers-with mouth dimensions of 8-1/2 x 3 inches. The front panel of the kg4 contains two white plastic-cone woofers, one above the other, with a nominal diameter of 8 inches. The dark brown, wood-framed cloth grille is retained by strong plastic fasteners and requires considerable effort for removal. ![]() Its handsomely finished oak-veneer enclosure is 24-1/4 inches high, 15-3/4 inches wide, and 10-3/4 inches deep, and the system weighs 45 pounds. The Klipsch kg4 is a two-way floor-standing speaker system featuring unusually high efficiency (for a home speaker) combined with an extended, smooth frequency response. ![]()
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