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KEF Kube 12 MIE 12" powered subwoofer

Item # 991KB12MIE

The Kube 12 MIE makes every listening, viewing, and gaming experience better with a healthy dose of deep, potent bass.

The Kube 12 MIE makes every listening, viewing, and gaming experience better with a healthy dose of deep, potent bass.

Item # 991KB12MIE

In stock

About the KEF Kube 12 MIE

Woody Sherman

Deep, clean bass for all your entertainment

The Kube 12 MIE brings together KEF's careful speaker design and high-tech digital signal processing for bass that's clean, deep, and satisfying. This hefty 41-pounder uses a custom 12" woofer in a sealed cabinet, driven by a built-in 300-watt Class D amp.

Deep, clean bass for all your entertainment

The Kube 12 MIE brings together KEF's careful speaker design and high-tech digital signal processing for bass that's clean, deep, and satisfying. This hefty 41-pounder uses a custom 12" woofer in a sealed cabinet, driven by a built-in 300-watt Class D amp.

Your viewing, listening, and gaming experience will be enriched by the substantial bass. Yes, the midrange and high frequencies are responsible for conveying detail and definition, but the bass is where the emotion lives. KEF's Music Integrity Engine® digital signal processing algorithms add depth, output, and dynamic range to the sub's presentation. And IBX Intelligent Bass Extension makes thousands of adjustments per second, to lower distortion and enhance your entertainment with world-class accuracy.


Product highlights:

  • frequency response: 22-140 Hz (±3dB)
  • proprietary Music Integrity Engine (MIE) leverages custom digital signal processing algorithms to provide optimal, accurate bass response from each model in the Kube family
  • built-in Class D amplifier delivers 300 watts RMS
  • custom-designed 12" woofer
  • compatible with the KEF KW1 wireless subwoofer adapter kit for easy room placement
  • iBX (Intelligent Bass Extension) digital signal processing provides deep, dynamic bass at any listening level
  • 3 placement presets (free standing, in-cabinet, or corner) let you choose your sub's location for optimal bass performance
  • variable low-pass crossover (40-140 Hz)
  • phase control switch (0°/180°)
  • line-level/LFE RCA inputs
  • speaker-level inputs with 4-pin Euroblock connector
  • main power on/off switch, auto standby/on mode, and 12V trigger power modes
  • detachable power cord
  • 15-9/16"W x 16-1/8"H x 17-3/8"D
  • weight: 41 lbs.
  • warranty: 5 years drivers, 2 years electronics

What's in the box:

  • Powered subwoofer
  • 6.5' AC power cord
  • Speaker-level input block
  • User Manual
  • Important Safety Information
  • Warranty Information

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More details on the KEF Kube 12 MIE

Stacey B.

Features & specs

Enclosure Sealed
Woofer Size (inches) 12
Woofer Composition Polypropylene
Firing Direction Front
Amplifier Output (watts) 300
Frequency Response 22-140 Hz
Preamp-Level Inputs Stereo RCA/LFE
Speaker-Level Inputs Phoenix
Speaker-Level Outputs No
Wireless Optional
Low-Pass Crossover Freq 40-140 Hz
High-Pass Crossover Freq 0
Phase Switch Yes
App Control No
Remote No
Other Info
Height (inches) 16-1/8
Width (inches) 15-9/16
Depth (inches) 17-3/8
Weight 41 lbs
Speaker Parts Warranty 5 Years
Speaker Labor Warranty 5 Years
Amplifier Parts Warranty 2 Years
Amplifier Labor Warranty 2 Years
The KEF Kube 12 MIE replaces these items:

Product Research


In-House Integration: KEF is one of the few high-end speaker manufacturers who design, engineer and assemble the driver, cabinet and circuitry in-house. This level of integration is the hallmark of KEF's commitment to pure sound. What you get is a driver, amplifier, and cabinet that is perfectly tuned for amazing bass performance.

  • 12" Long Throw Woofer: The Kube 12 MIE powered sub houses a front-firing 12" long throw woofer with high excursion that delivers high output and deep, articulate low frequency bass. The front-firing design creates a sensation of direct force into the room, creating a tactile, pressured, and powerful bass response. With high SPL and low-frequency extension, Kube MIE series powered sub faithfully reproduces the lowest octaves in both movies and music, ensuring an immersive, impactful sonic bass experience.
  • Sealed Cabinet: The Kube MIE series powered subwoofer utilizes a sealed (acoustic suspension) cabinet for greater accuracy and delicate musical detail, while allowing the Kube MIE subwoofers to be installed almost anywhere; even inside a piece of furniture..
  • 300W Class D Amplifier: Optimally designed for the 12" woofer and the available acoustic volume of the sealed cabinet, the 300W (RMS) Class D amplifier of the Kube 12 MIE runs efficiently and cool, providing ample power for the subwoofer. It reproduces deep bass and rumble with precision and dynamics, adding intensity and realism to your audio experience.

Music Integrity Engine (MIE): The Kube MIE series powered sub employs KEF's Music Integrity Engine (MIE) that includes Intelligent Bass Extension (iBX) and placement-dependent equalization (EQ) for high performance bass in practically any room and application. KEF’s Music Integrity Engine (MIE) is a proprietary suite of in-house written DSP (Digital Signal Processing) algorithms that serves up detailed and accurate sound from the Kube MIE series powered sub. Tailored for each particular model, this ensures that every component of the powered sub works in perfect harmony to an even higher level than would otherwise be possible.

  • Intelligent Bass Extension (iBX):  Part of the Music Integrity Engine (MIE), Intelligent Bass Extension (iBX) creates an extended depth that unlocks the full potential of the long throw woofer driver. By analyzing the audio input signal and making multitudes of tiny adjustments every second, iBX allows the Kube MIE series subwoofer to play louder and remain dynamic at any listening level. In step with the advancements developed by KEF's Music Integrity Engine (MIE), the latest version of Intelligent Bass Extension (iBX) lowers distortion still even further. The end result is remarkable low frequency bass accuracy.
  • Placement Dependent EQ Section: Thanks to KEF's Music Integrity Engine (MIE), the Kube MIE series powered sub also features a placement-dependent EQ section that can be easily adjusted to maximize in-room performance. With 3 room placement setting options, the powered subwoofer easily fits into almost any environment, ensuring consistent performance wherever it is placed - whether snugly fitted in a cabinet, against a wall or in a corner.

Rear-Panel Controls: Rear-panel controls (consisting of Volume Level, Crossover Frequency, Phase and EQ Presets) help match the powered sub to your speaker system and room placement.

  • Volume Level: The volume control adjusts the output level of the powered subwoofer in relation to the main loudspeakers.
  • Crossover Frequency: The crossover frequency control changes the upper cut-off frequency of the subwoofer. Its effective range is from 40Hz to 140Hz at a rate of 24dB per octave. The frequency control should be adjusted to achieve the smoothest integration and transition between the main loudspeakers and the subwoofer.
  • Phase Control: The phase control will normally be set at 0°, but more output level can sometimes be achieved in the 180° position; in particularly when the subwoofer is far away from your main loudspeakers.
  • Placement Tuning Presets: There are 3 intuitive preset options that ensure excellent performance from the Kube MIE series sub no matter where in the room it is placed. You can choose from Free Standing (in-room), Wall/Cabinet (in-wall), or Corner (corner install).

LFE/RCA & Speaker-Level Inputs: The Kube MIE series powered sub provides LFE, line-level, and speaker-level inputs to connect to a variety of AV receivers and integrated amplifiers. KEF's SmartConnect intelligent LFE and line-level inputs automatically detect a mono or stereo signal and adjusts the subwoofer volume level accordingly.

  • LFE (Low Frequency Effect): Thanks to KEF's SmartConnect technology, either the Left or Right line-level input can be used as a LFE input and connected to your AV receiver's LFE output. In this setup, your receiver's built-in crossover settings will be utilized instead of the the powered sub's. Make sure the sub's crossover is set to "LFE".
  • Line-Level: If your receiver or integrated amplifier is not equipped with a LFE output but does have line-level outputs, you can use the powered sub's stereo line-level inputs to connect the subwoofer to your receiver or integrated amp.
  • Speaker-Level: The speaker-level input consists of a detachable 4-pin phoenix-style (euroblock) connector. These speaker-level inputs connect to the main speaker-level outputs of your receiver or integrated amplifier which is not equipped with an LFE out or line-level outputs.

Optional Wireless Adapter: The KEF KW1 Wireless Subwoofer Adapter (sold separately) allows you to wirelessly transmit the low-frequency audio signal from your AV receiver, preamplifier, integrated amp, or powered speakers to the Kube MIE series powered sub. The KW1 Wireless Subwoofer Adapter consists of a wireless transmitter (TX) and wireless receiver (RX). The KEF KW1 provides a high-quality wireless transmission that delivers every ounce of detail and impact from your movie and music soundtracks. The KW1 operates in the high-bandwidth 5GHz RF band with an auto-selectable digital wireless link of 5.2GHz or 5.8GHz. It delivers a wireless audio signal up to 24-bit/48kHz that is near lossless with a low-latency of less than 17ms. The KW1 has a wireless range of approximately 49' (15M). Pairing is intuitive and simple with a pairing button on the transmitter and receiver. Simply, press both buttons to pair the two devices.

  • Transmitter (TX): The KW1's wireless receiver features a set of stereo RCA jacks that allow for connection to your AV receiver's, preamplifier's, integrated amp's, or powered sub's subwoofer/LFE output. The wireless transmitter does not come with its own power supply and receives its power via USB. You'll need an external USB/AC power adapter (sold separately - see Accessories Tab) or an AV receiver, preamplifier, integrated amp, or powered speakers with a USB (5V/1A) charging port to power the wireless receiver. The wireless receiver can simply be placed on top of your component or on a shelf next to your component.
  • Receiver (RX): The KEF KW1's wireless receiver simply plugs into the KEF Kube MIE series powered sub's proprietary "Expansion" port to receive its wireless audio signal from the system's wireless transmitter. The proprietary "Expansion" port on the Kube MIE series subwoofer also powers the wireless receiver (no external AC adapter or USB port required). Once the wireless receiver is plugged into the "Expansion" port, it is secured to the back of the powered sub by the included screws.

Note: The KEF KW1 Wireless Subwoofer Adapter comes with only one wireless receiver, but can support up two wireless receivers for a wireless connection of up to two KEF Kube MIE series powered subs. An additional KW1-RX wireless receiver is available and sold separately.

Multiple Power Modes: You can choose between 3 Power Modes. The Auto Wake Up mode detects audio signals for instant readiness, while the Always On mode keeps it ready to play instantly. There is also a 12V Trigger mode that provides automatic wake-up from the 12V Trigger output of your AV receiver or integrated amp..

  • Detachable AC Power Cord: The included 6.5' AC power cord (2-prong, C7) plugs into the back of the powered subwoofer and into and AC power outlet or surge protector/line-conditioner (sold separately).
  • 12V Trigger Input: The 12V Trigger In (3.5mm) plugs into the 12V Trigger Out of your AV receiver or integrated amp using a mono-minijack cable (sold separately). When this connection is made, the powered sub will automatically turn on with your AV receiver or integrated amplifier.

Placement Options: As the bass (low-frequency) sound produced by the subwoofer is non-directional it can be positioned anywhere in the room, although it should not be placed too close to the listener. The Kube MIE series subwoofer is a front-firing configuration, therefore you may place the unit close to wall or structures on the right and left sides. For optimum performance, try the subwoofer in different positions to find the best place for a "boom-free" sound. To aid in placement, the Kube MIE offers 3 placement preset EQ options - Free Standing (in-room), Wall/Cabinet (in-wall), or Corner (corner install).

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