Subwoofers — KEF Kube 15 MIE

The Kube 15 MIE is the largest subwoofer in KEF's Kube MIE range, using a 15-inch driver and intended for large living rooms and dedicated home cinemas. MIE stands for Music Integrity Engine, the in-house DSP platform KEF developed for the LS60 Wireless and KC62 and then adapted to each Kube model to improve accuracy at high output levels.

Key specs that matter

This is a sealed-box powered subwoofer with one front-firing 380mm (15-inch) long-throw driver and a 300W RMS Class D amplifier. Frequency response is 20Hz to 140Hz (+/-3dB), and maximum output is 116dB. The variable low-pass filter covers 40Hz to 140Hz, and an LFE setting bypasses it. Inputs are RCA phono sockets, and a speaker-level connection is made through an expansion port. Power consumption is 300VA from a 100 to 240V supply. Including the rear panel and feet, the cabinet measures 519 x 500 x 515mm, and it weighs 27.5kg.

Engineering and use context

The large cone and long excursion move the volume of air needed for high output at the lowest frequencies without pushing the driver to its mechanical limits, and the front-firing layout sends that energy straight into the room. A sealed enclosure instead of a port gives a gentler low-frequency roll-off and no port noise. It also makes the subwoofer less sensitive to placement, so it can stand by a wall or be built into furniture. Within the Music Integrity Engine, KEF's iBX Intelligent Bass Extension analyses the incoming signal continuously and makes many small adjustments every second. This extends bass depth while keeping the driver within safe limits, so the subwoofer can play louder with less distortion. The latest version of iBX lowers distortion further than in the original Kube series. The Class D amplifier was designed for this driver and cabinet volume and runs efficiently and cool. Intelligent input detection and KEF SmartConnect make it simpler to connect different sources and KEF wireless speakers.

Pairing

Set to LFE, the Kube 15 MIE plugs straight into the subwoofer socket of a home cinema amplifier. For a stereo setup whose amplifier lacks a subwoofer output, the speaker-level connection and variable low-pass filter do the job. The optional KEF KW1 wireless kit removes the long signal cable, so the subwoofer can go wherever it fits the room best.

Alternatives

The KEF Kube 12 MIE has a 12-inch driver in a smaller cabinet for medium-sized rooms.