KEF C20 Bookshelf speakers

The C20 can accommodate a larger B200 (185mm cone) drive unit in its larger cabinet. The free-air resonance now drops to 35Hz, taking the low frequency response down about half an octave below the C10. The crossover, still at around 2.8kHz, uses two additional components to form a flattish, series-resonant dipper across the bass/midrange unit to level the working response and still includes the 600μF series capacitor. The sound of the C20 was more open than the C10, and the boxy trend had departed. However the sibilant characteristic was much more prominent and lower down the frequency scale than before, and fully merited that descriptive word 'splitchy' which is in no dictionary that I have eve r consulted but is nevertheless essential vocabulary. This same fault, which seems to be a characteristic of polypropylene cones, lent a hard, almost glassy, edge to some well loved sopranos. It was a relief to discover that it could be considerably concealed, although not removed, by the simple expedient of not listening on the axis. Turning the two loudspeakers inwards some 30° was effective but produced a very narrow stereo image. Experimentally I moved them closer together and turned them outward and bingo, there was a room full of music. I have since repeated the arrangement in another room and it still worked. Not an ideal way to listen, perhaps, but it turned a loudspeaker which I was prepared to dismiss as too brash into one where I could switch to Radio 3 and use it for a whole 'Prom' in reasonable contentment.