The Kube 8 MIE is the entry model in KEF's Kube MIE range, a four-strong line of sealed, powered subwoofers that runs from this, the most compact, up to the considerably larger Kube 15 MIE. KEF positions it for smaller rooms, but it shares the same 300W RMS Class D amplifier as its larger siblings, and it carries the same Music Integrity Engine digital signal processing suite, which KEF tailors to each model in the range. It is offered in a single black finish.
Driver and cabinet
A single 200mm long-throw driver fires forward from a sealed cabinet. KEF's reasoning for the front-firing arrangement is output: a large cone area and high excursion deliver higher output at lower frequencies, and a sensation of direct force into the room. The sealed enclosure is chosen for accuracy, and because it allows the Kube to be installed inside a cabinet. Since the driver fires forwards rather than downwards, KEF states the subwoofer may be placed near walls, in corners, or even built into walls and cabinets. Frequency response is quoted as 34Hz to 140Hz at -6dB, with a maximum output of 105dB.
Music Integrity Engine
Music Integrity Engine (MIE) is KEF's in-house suite of DSP algorithms, tailored to each model in the range, written to make every component of the subwoofer work in perfect harmony. Within it sits iBX Intelligent Bass Extension, which analyses the input signal and makes many small adjustments every second so that the subwoofer can play louder and stay dynamic at any listening level. KEF says the new version of iBX lowers distortion still further, in step with the wider Music Integrity Engine advances that drew on the development of the LS60 Wireless and KC62.
Room placement and setup
Three room placement EQ settings match the response to where the subwoofer ends up: In-room for free standing use, a combined Wall or Cabinet position, and Corner. The rear panel adds a variable low pass filter adjustable from 40Hz to 140Hz at a rate of 24dB per octave, an LFE setting for use when bass management is handled by an AV receiver or processor, a phase control switchable between 0 and 180 degrees, and a rotary volume control for balancing the subwoofer against the main speakers.
Connections and power
Line-level RCA phono inputs carry KEF SmartConnect, which automatically detects whether the incoming feed is mono or stereo and adjusts the subwoofer volume level accordingly. Speaker-level inputs are provided as well, through the supplied Euroblock connector, for amplifiers without a dedicated subwoofer output. Three power modes are selectable on the rear panel: auto wake up, which powers the subwoofer on when it detects an audio signal and turns it off again after 20 minutes of inactivity; always on, which keeps it ready to play instantly; and 12V trigger, for switching on with a compatible amplifier or receiver. An expansion port accepts the optional KW1 Wireless Subwoofer Adapter Kit, sold separately, where a cable run to the listening position is impractical.