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KEF KUBE 12b

Powered subwoofer

Item # 991KUBE12B

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Overview

Our take on the KEF KUBE 12b

Don't tell my wife, but when I have the house to myself I like to watch movies really loudly. And a large part of what makes that such a rush for me is the visceral feel of bass as it sweeps through my living room during intense scenes. Talk about thrilling! KEF's KUBE 12b powered subwoofer has this exact goal in mind: provide deep, hard-hitting bass that puts you right in the heart of the action. 

Deep, accurate bass from KEF

Don't tell my wife, but when I have the house to myself I like to watch movies really loudly. And a large part of what makes that such a rush for me is the visceral feel of bass as it sweeps through my living room during intense scenes. Talk about thrilling! KEF's KUBE 12b powered subwoofer has this exact goal in mind: provide deep, hard-hitting bass that puts you right in the heart of the action. 

Intelligently designed components

The KUBE 12b is outfitted with a custom-designed 12" woofer, and a powerful 300-watt RMS amplifier. KEF designs and builds all of their components in-house to make sure that both the quality and audio performance are up to the company's high standards. Use this sub with confidence as part of your home theater or stereo music system, even in large rooms.

Built-in sound controls

On the back panel you'll find a simple-but-useful input and control panel. My favorite feature? You can choose from three placement presets (free-standing, in-cabinet, or corner) to dial in the sound based on where the sub is located in your room.

Get the most out of your new sub

Once you get your sub home, check out our tips for placement and setup. Free lifetime Virginia-based tech support is included with your purchase.

Product Highlights:

  • frequency response: 22-140 Hz (-6 dB)
  • built-in Class D amplifier delivers 300 watts RMS of continuous power
  • custom-designed 12" woofer
  • acoustic suspension (sealed) cabinet design
  • 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
  • main power on/off switch plus auto standby/on mode
  • detachable power cord
  • 15-1/2"W x 16-1/8"H x 16-1/8"D
  • weight: 45.5 lbs.
  • warranty: 5 years woofer, 2 years amplifier
  • Our 60-day money-back guarantee

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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Details

Hands-on research

Features and Specs

Enclosure Acoustic Suspension
Video Shielded No
Woofer Size (inches) 12
Woofer Composition Not given
Firing Direction Front
Wireless No
Preamp-Level Inputs Yes
Speaker-Level Inputs No
Speaker-Level Outputs No
Low-Pass Crossover Freq 40-140 Hz
High-Pass Crossover Freq 0
Phase Switch Yes
Amplifier Output (watts) 300
Frequency Response 22-140 Hz
Height (inches) 16-1/8
Width (inches) 15-9/16
Depth (inches) 17-3/8
Weight 45.5 lbs
Speaker Parts Warranty 5 Years
Speaker Labor Warranty 5 Years
Amplifier Parts Warranty 2 Years
Amplifier Labor Warranty 2 Years

Product Research

Features

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" Woofer: The Kube12b features a front-firing 12" woofer that has been designed, built, and integrated in-house by KEF for a new level of optimization that delivers deep, articulate bass. The 12" powered subwoofer is perfect for smaller rooms.

300W Class D Amplifier: The powered sub's 12" woofer is driven by a 300 watt Class D amplifier with a formidable 56-bit 50 MIPS DSP preamplifier for immersive, dynamic bass performance.

iBX Technology: iBX technology extends the bass depth dynamically, unlocking the full potential of the driver's power at normal listening levels or even the most extreme. KEF's design and engineering team worked in chorus to develop iBX. This Intelligent Bass Extension algorithm creates an extended depth that unlocks the full potential of the custom driver; giving you unparalleled precision and ultimate synchronicity between amplifier, driver and sealed cabinet. The DSP analyses your input signal and applies KEF's iBX, allowing the subwoofer to play louder and remain dynamic at any listening level.

Sealed Cabinet: The Kube series powered subwoofer utilizes a sealed (acoustic suspension) cabinet for greater accuracy and delicate musical detail, while allowing the Kube subwoofers to be installed almost anywhere; even inside a cabinet.

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 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 achieve in the 180° position; in particularly when the subwoofer is far away from your main loudspeakers.
  • Placement Tuning Presets: There are placement tuning presets for free standing (in-room), wall/cabinet (in-wall), and corner installations, so the powered subwoofer sounds great no matter where you position it.

LFE/RCA & Speaker-Level Inputs: The Kube series powered sub provides LFE, line-level, and speaker-level inputs to connect to a variety of AV receivers and integrated amplifier. 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 phoenix-block 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.

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 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.

Our Product Research Team

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