The KEF KC92 Subwoofer: 11Hz Deep Bass, Small Box!

In my search for small subwoofers, I came across KEF’s tiny KC62 subwoofer ($1,500), which has been a huge hit for the British brand. It has an appealing form-factor and the ability to produce incredibly deep bass via a pair of force-cancelling 6.5-inch drivers powered by 1,000 watts RMS of specially-designed Class D amplification. The only downside to this sub is its inability to play loud. Enter the new KC92 ($2,000), which capitalizes on everything KEF learned in developing the KC62, but with 9-inch drivers in a larger (but still compact) cabinet. The new sub takes advantage of KEF’s Music Integrity Engine (MIE), a proprietary DSP algorithm that is tailored for each model to ensure that “every component works… in perfect harmony,” to elevate the overall performance and deliver “remarkable integrity, detail, and accuracy of sound,” according to the company. Powered by MIE, the iBX Intelligent Bass Extension feature “creates an extended depth that unlocks the full potential of the custom driver.” This feature analyzes the input signal, allowing the sub to “play louder and remain dynamic at any listening level,” according to KEF.

The KC92’s force-cancelling drivers incorporate KEF’s patent-pending P-Flex Surrounds, reportedly inspired by the Japanese art of origami. They use pleats in the surround material (similar to origami folds) to defy internal air pressure and allow the driver to move more precisely in response to the audio signal without sacrificing sensitivity, according to the company. The results are said to be deeper bass extension and more detailed bass reproduction with high linearity and vanishingly-low distortion, regardless of the volume level. 

The KC92 has a max SPL of 110 dB. The KC62 maxes out at 105 dB. Kef doesn't specify the frequency bandwidth or distortion level for these outputs, but it's safe to assume the spec done in a similar manner for both. If you aren’t familiar with the way the decibel scale works, a difference of 5 dB might not seem very significant, but it’s actually huge at bass frequencies. This should allow the KC92 to excel in larger rooms — up to about 540 square feet, according to KEF. (And if you use multiple subs, as we always recommend, you could use them in an even larger space.) The KC92’s frequency response is also remarkable for such a small design; it reportedly plays down to 11Hz (-3dB), thanks to “optimized excursion characteristics.” The sub’s cabinet measures just 13.88 inches tall, 13 inches wide, and 14.19 inches deep. Inside, there are two 9-inch drivers that use a concave aluminum skin to strengthen a paper cone. The vented voice coils and enlarged motor systems are arranged back-to-back, reducing cabinet vibration for maximal precision and detail. Because the cabinet is larger than that of the tiny KC62, KEF did not need to use that sub’s unique Uni-Core driver design, which places one voice coil sleeved inside the other. But like the KC62, the KC92 uses a dedicated 500-watt RMS Class D amplifier for each driver. KEF says this helps the sub to deliver “sudden bursts of power” when needed, while maintaining incredible control to guarantee timing accuracy and dynamic response.

Other features include both line level and speaker level inputs, and a line output with a built-in High Pass Filter for the main speakers. KEF’s SmartConnect feature automatically optimizes gain based on whether a mono or stereo input signal is received. There are four room placement settings (free space, wall, corner, and cabinet), and a dedicated “apartment mode,” to avoid complaints from the neighbors. Available in White Gloss and Black Gloss, the KC92 should begin shipping by mid April, 2024. The KC92 was launched alongside new versions of KEF’s KUBE subs, now with MIE. These will be available in four driver sizes: 8 inches ($600), 10 inches ($800), 12 inches ($1,000), and 15 inches ($1,400). 

More information: KEF KC92

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