Vintage

This final version of KEF’s Cantor series gained a 200mm ABR but lost some cabinet depth, reducing the internal volume to ~17 ltrs. Nevertheless, by trading the mass of air in a port for the less turbulent/lower excursion mass of an ABR tuned to 30-100Hz (–3dB), KEF has drawn the Cantor III’s bass extension down to 45Hz (–6dB re. 200Hz). Despite a mild cone mistermination before crossover between the B160 bass/mid and T33 tweeter [see also CSD waterfall, Graph 2] the forward response is still flat in trend [see Graph 1] – a feature carried through to KEF speakers of today despite generations of designers having passed through.

The response errors are a fine ±2.7dB/±3.3dB, respectively, and the pair matching good to 1.2dB through the midrange (all re. 200Hz-10kHz). The response of the T33 soft dome tweeter dives beyond 20kHz to 24-25kHz (–6dB re. 10kHz) but is free of harsh resonance and, thanks to the roll-off, exhibits a very low ~0.15% distortion beyond 10kHz (re. 1m/90dB SPL). The classic frame grille brings some added variation in the presence region [blue trace, Graph 1] while toeing-in the boxes by 15o gently softens the treble a little further [grey trace, Graph 1].

Compared with contemporaries of today the Cantor III is slightly insensitive (86dB) but a very easy drive, the impedance modulus never falling below 6ohm and hitting a min. 6.3ohm at 14kHz where high currents are very unlikely with typical music playback. The more relevant minimum of 6.47ohm/198Hz follows swings in impedance phase of +41o/22Hz and –44o/91Hz that contribute to the modest 3.1ohm EPDR at 128Hz – again, this will not give even a mild-mannered integrated pause. PM

Above: Response inc. nearfield bass driver and ABR [green], freefield corrected to 1m at 2.83V [yellow], ultrasonic [pink]. Left, black; right, red; ±15o, grey

Above: The high treble is ‘clean’ but there are obvious modes associated with the bass/mid and ABR drivers