The KF92 Subwoofer Goes to Eleven

To reproduce serious bass you need a completely different kind of loudspeaker, one which can cope with huge pressure. KF92 is engineered to blast out huge chunks of lower frequency energy, yet is subtle enough to pick out the delicate details of a double bass. KF92 is a compact, room-friendly subwoofer engineered to deepen every listening experience with two massive 9-inch drivers in a force-cancelling configuration are powered by an immense 1000 Watts (RMS) of power. Optimised with KEF's Music Integrity Engine™, KF92 delivers astonishing levels of deep and controlled bass. KF92 ensures you don't just feel the air move - you feel the sound move you.

Here’s a look at some of the features that make the KF92 a game-changer:

Outward Appearances

The KF92 features the same black gloss finish that defines our R Series. Sleek, curved lines also define the look of the KF92, eliminating the harsh square lines and boxy look of traditional subwoofers. The heatsink design is a direct result of our LSX and LS50 Wireless engineering, providing a pleasing aesthetic form and the necessary function to keep the internal electronics operating at their optimum level.

1000W of Pure High-End Power
Each driver is fed by a powerful 500W Class D amplifier that was specifically designed for the KF92. Class D amplification offers the ability to produce a tremendous amount of power without the hassle of worrying about the excess heat Class A and A-B drivers produce.

Customised DSP and Music Integrity Engine™
Our proprietary Music Integrity Engine™ and Intelligent Bass Extension (iBX) allow for dynamic bass extension at regular listening levels down to 11Hz. You can’t hear 11Hz, but you can feel it, and more importantly, by being able to play that low, we ensure that the very lowest frequencies we can hear are reproduced cleanly and quickly, with no distortion.

Room Placement EQ
With five bespoke EQ settings, optimal performance is easily attained regardless of where you place your KF92, whether it’s set up in free space, near a wall, in a corner, in a cabinet or even in an apartment setup.

New Driver Design
Benefiting from the technologies used in our Reference and R Series, the hybrid aluminum/paper cone KF92 drivers feature over-sized magnets for incredible driver control, speed and power. The drivers are vented for further power handling and control and the cone geometry has been carefully designed to reduce unwanted resonances and cone breakup. We use a hybrid aluminum/paper cone to get the best of both worlds when it comes to driver material: the paper cone provides low-mass and accurate response, while the aluminum skin provides more overall strength and better damping.

Force Cancelling Drivers
Two drivers will move more air than one driver and more air moved equals greater overall SPL (volume), but there’s also a fundamental problem with single-driver subwoofers: For every action there is an equal and opposite reaction (Newton’s Third Law). As the driver cone pushes backwards it exerts a force on the basket and that energy is transferred to the cabinet. In extreme cases a subwoofer will actually “walk” across the floor as a result of this unwanted energy. This is not good for clean audio performance – all of that.

By coupling two drivers to each other, the reactive forces of each are canceled, leaving no excess energy to excite the cabinet and interfere with the bass response of the drivers. The result is cleaner bass response free from damaging cabinet vibrations AND an additional 6dB of overall bass response than what would be expected from drivers of the same size in a non-force canceling configuration.

Controls & Inputs
In some cases, a mono input from an AC Receiver (for example), only half of the input level is presented to the subwoofer. Half the input level means the subwoofer has to work twice as hard to produce the volume you are looking for; a subwoofer that is working too hard adds distortion. KEF’s SmartConnect technology determines if you are using a mono input or a stereo input and adjusts the gain to ensure you are getting the proper input level.

The KF92 features speaker-level inputs for setups where a line-level input from the receiver or amp is not available. Line-level outputs allows you to daisy-chain multiple KF92s for smooth, standing wave-free performance in any room. A high-pass filter, for even better control and quality, is also available for flexibility in advanced installations.

The Control Panel

Expansion Port: future-proofs KF92 allowing for future accessories.

Crossover: A Low Pass Filter from the inputs allows for smooth integration with the main loudspeakers.

Volume: The volume control has been designed to work the same way the human ear works: from around halfway on up, the increments are smaller allowing for even finer tuning at higher volumes (algorithmically rather than linearly) – where fine tuning of output is more critical for ultimate performance.

Mode (Manual/LFE): Manual utilizes the internal crossover and LFE is used with Home Theater configurations where the AV Receiver controls the output to the subwoofer.

EQ: Allows you to set your KF92 in five different settings (free air, wall, corner, cabinet, apartment).

Phase: Switches between 0° and 180° for optimal performance integration with the main loudspeakers.

Ground Lift: Safely breaks the ground connection in the event of a ground loop or AC sneak path that causes low frequency (60 cycle) hum.

Speaker Input: Connect the high-level output of your amplifier to the KF92.

Line Input (with SmartConnect): For either mono, L/R or LFE connection. SmartConnect ensures proper input gain.​​​​​​​

Line Output HPF: Adjustable High Pass Filter for the Line Outputs in daisy chain configurations.​​​​​​​

Line Output: Configure KF92 with other subwoofers or amps as part of a complete multi-device system.