KEF C40 Bookshelf speakers

On then to the C40, a logical successor to the Carina, with a second B200 unit operating at low frequencies only. These two 3-ohm B200s have a free-air resonance of 40Hz. The two together, connected in series to give 6 ohms and shunted by capacitors of 10μ and 100μF respectively, produce a resonant frequency of 85Hz in this quite large box. KEF have reverted to third order loading here, with a 450μF capacitor in series and this has resulted in a nice clean bass end of apparently limitless power. A low floor-stand of 13 to 25cm height is suggested, but operation on the floor itself is not out of the question and was indeed preferred on some programme material. The cabinet colouration is now low down and comparatively innocuous; the sibilance is still present but less obvious and, if the loudspeakers are being used on the floor, one is automatically off-axis vertically. Driven by a pair of 100-watt amplifiers, these C40s with their true sensitivity of 91dB at 8 ohms, are capable of very loud so und s indeed and they remain clear and undistorted right to the amplifier limit. This is a level at which I feel inclined to leave the room but, as KEF succinctly put it, "it will be particularly appealing to the cost-conscious rock listener". Amen to that.