KEF iQ30

KEF iQ30 loudspeaker review

From Hi-Fi World - January 2009 issue





Part of KEF's new iQ range, the 6.7kg iQ30 is described as a shelf mounter, but at 327mm deep (13in) it barely fits a 12in shelf; like B&W's 685 it really needs stands. Measuring 386mm high and 220mm wide it is of similar dimensions to the B&W, occupying the same market slot, that of a small loudspeaker with a big sound. KEF fit a 165mm cone version of their unique Uni-Q drive unit, where the tweeter fires from the centre of the bass unit cone. This arrangement gives even dispersion and both focused and consistent imaging, regardless of listener position. Helping disperse treble is a Tangerine waveguide, but measurement showed the iQ30 still sounds smoothest off-axis, and a little bright on-axis. This may well be to match the 685s on-axis sound. However, the iQ30 is even more sensitive so will sound louder in an A/B demo. Offering a claimed 89dB from one nominal watt, even a 40 Watt amplifier will sound loud with this loudspeaker.


Listening to the KEF iQ30s after the B&W 685s showed that although apparently similar they are different as chalk and cheese. The iQ30s image in the plane of the loudspeakers, and between them. They sound less expansive, but more dense and solid in image quality, and very strongly focussed. Spinning Gerry Rafferty's The Ark underlined good midband clarity, a trace of boxiness heard as small 'boof' issuing from the port and well balanced bass. However, the new treble unit sounds steely even well off-axis and this brought and obvious 'schhh' to cymbals on Duffy's Warwick Avenue, on both CD and LP.  The new tweeter remains both hard and intrusive, robbing brass of its characteristic sonority and this both dominated and diminished the timbral resolution of the iQ30s. So with the Eagles 'Somebody' both 'shoulder' and 'icy' had a lacerative sibilant edge and the balance was too tilted toward highs, even though I was listening far off axis. This made listening to old, less clean recordings quite difficult at times as they could sound harsh. As I noted with the B&W 685 review our Sugden A21a amplifier exacerbated the effect; the iQ30s need a softer delivery from a Naim Nait or NAD C315BEE perhaps. All the same, the iQ30s were quite obviously clear and detailed, apparently fast with transients and had clean, tuneful bass that was far from heavy. Unfortunately, their balance was challenging with classical strings, although horns blared strongly in Wagnerian climaxes and kettle drums were suitably weighty, if not thunderously deep.

verdict 4

Small loudspeaker with a big sound,  marred by monotonicity.

KEF iQ30  £350

+44 (0) 1622 672261


- clean, solid bass

- tonally wide and even

- superb imaging


- hard edged vocals

- steely treble

- occasionally sibilant


Frequency response of the iQ30 gets ragged and peaks at high frequencies, on-axis. Off axis by around 30 degrees it smooths considerably, our analysis shows. Bass reaches down to 50Hz, port output at 48Hz ensuring there’s little below this frequency. Third octave analysis shows that, off axis as intended the iQ30 measures flat and wide. It is very accurate, but there’s a little emphasis around 200Hz to add body to the sound. Strong port output around 700Hz may be audible as colouration.

Sensitivity was highest of the group at 88.5dB from one watt, helped by a low-ish measured impedance of 5.4 Ohms, with minima of 4 Ohms. The load is fairly reactive, which affects amplifiers. Spectral decay revealed no problems and distortion was low. The iQ30 measures well all round. It is very accurate, wideband and sensitive. NK


kef iq 30  stepped sine fr2 screen

Green - driver output; Red - port output


kef iq 30   z4  screen


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