9/1/2023 0 Comments Kef ls50 meta uk![]() The two models offer identical in-room responses below 300Hz. The Meta's dispersion, like that of the original LS50, is very uniform in both horizontal (fig.5) and vertical (fig.6) planes, with well-controlled narrowing of the radiation pattern in the top octaves.įig.7 KEF LS50 Meta, spatially averaged, 1/6-octave response in JA's listening room (red), and of original LS50 (blue). As with other recent loudspeakers from KEF that use the coaxial Uni-Q drive-unit, including the earlier LS50, there are no discontinuities in the mid-treble that might be due to destructive interference between the direct radiation from the tweeter and reflections of that radiation from the circumference of the woofer cone. The tweeter's output remains at full level almost to the 20kHz limit of this graph. The LS50 Meta's farfield output, averaged across a 30° horizontal window centered on the tweeter axis (fig.4, black trace above 300Hz), is superbly even from the lower midrange through the treblebetter, in fact than that of the original version. The partnering amplifier needs to be comfortable driving 4 ohms.įig.4 KEF LS50 Meta, anechoic response on HF axis at 50", averaged across 30° horizontal window and corrected for microphone response, with nearfield responses of woofer (blue) and port (red) and their complex sum (black), respectively plotted below 312Hz, 1kHz, 312Hz. The LS50 Meta has minimum EPDRs of 1.66 ohms between 135Hz and 140Hz and 1.7 ohms between 660Hz and 725Hz, both regions where music can have high energy. ![]() The new speaker's electrical phase angle (fig.1, dashed trace) is occasionally high, and I used the formula in a 1994 JAES paper to calculate the "equivalent peak dissipation resistance" (EPDR, footnote 1). The Meta remains closer to 4 ohms for longer in the midrange but has a considerably higher magnitude in the crossover region. ![]() Below 200Hz, it is almost identical to that of the 2012 LS50 (fig.2, solid trace), but at higher frequencies the impedance traces are quite different. The solid trace in fig.1 shows how the Meta's impedance magnitude varies with frequency. My estimate of the LS50 Meta's voltage sensitivity was 84.5dB(B)/2.83V/m, which is the same as that of the original LS50 and within experimental error of the specified 85dB. I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the KEF LS50's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield and spatially averaged room responses. ![]()
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