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KEF KUBE 8b Subwoofer Review

Main Features

  • 8" Not given Woofer
  • 300 watts RMS Output
  • 34-140 Hz Frequency Response
  • Built-in DSP with Room Correction
  • Weight: 25.00 lbs / 11.36kg
  • Dimensions (H x W x D): 11-9/16" x 11-5/8" x 13-5/16"
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KEF KUBE 8b Subwoofer Review

KUBE 8b is a Sealed type Powered Subwoofer by KEF with a frequency range of 34-140 Hz. It features 1 x 8" Not given Woofer, and powered by a Class D 300 watts amplifier.

KUBE 8b is a member of KEF's KUBE series of Powered subwoofers. Below you can see the main specs of these subwoofers as well as review and comparison links.

KEF KUBE Series Subwoofers
Model Frequency Woofer Amp Power Weight
KEF KUBE 8b
34-140k Hz 8" 300 watts 11.36kg
KEF KUBE 10b
Compare
24-140k Hz 10" 300 watts 17.50kg
KEF KUBE 12b
Compare
22-140k Hz 12" 300 watts 20.68kg


**This post contains affiliate links, and I will be compensated if you make a purchase after clicking through my links. As an Amazon Associate I earn from qualifying purchases.

Frequency Response

KEF KUBE 8b has a Frequency response range of 34-140 Hz at ±3dB. Here we have a comparison of how KUBE 8b's Low and High frequency values compare with the average, max and min Low and High frequency values in its class.

Low Frequency
Powered Subwoofers
KEF KUBE 8b
Min
Average
Max
High Frequency
Subwoofer Speakers
KEF KUBE 8b
Min
Average
Max

Among all subwoofers in our database with a max MSRP price of 750$, these are the 5 Powered Subwoofer models that can reach deeper bass levels than the KEF KUBE 8b's 34Hz:

  • GoldenEar ForceField 3 with Low Frequency of 18 Hz (Compare w/ KUBE 8b)
  • SVS PB-1000 with Low Frequency of 19 Hz (Compare w/ KUBE 8b)
  • SVS SB-2000 with Low Frequency of 19 Hz (Compare w/ KUBE 8b)
  • Klipsch RP-1000SW with Low Frequency of 19 Hz (Compare w/ KUBE 8b)
  • SVS SB-1000 Pro with Low Frequency of 20 Hz (Compare w/ KUBE 8b)


Low-Pass Crossover

KEF KUBE 8b has a variable Low-pass filter (LFP) which lets you choose a frequency level between 40-140 Hz in order to block any frequencies above that point from reaching the amplifier.

KEF KUBE 8b Back View
KEF KUBE 8b Back View

Inputs and Outputs

  • PreampLevel Inputs: Stereo RCA/LFE
  • SpeakerLevel Inputs: No
  • SpeakerLevel Outputs: No
  • Wireless: No

KEF KUBE 8b External Dimensions and Weight

KEF KUBE 8b has external dimensions of (Height x Width x Depth) 11-9/16 x 11-5/8 x 13-5/16inch (294.0 x 296.0 x 339.0mm ).

Base Surface Area
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited. The base area of KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2.

To get a better perspective on the real life size of KEF KUBE 8b, let's compare it with a standard size Compact Disc which has a diameter of 4.7inch (120mm).

KEF KUBE 8b Real Life Body Size Comparison
KEF KUBE 8b Speaker Size Compared to a Compact Disc

Here we place the KEF KUBE 8b virtually next to a standard width amplifier and turntable on a media center to get a better idea about the size.

KEF KUBE 8b placed next to a Media Stand
KEF KUBE 8b Subwoofer next to a Media Stand

Weight

The KEF KUBE 8b weighs 11.36kg / 25lbs. Weight of a subwoofer is an important factor when you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. Here is a comparison of how KUBE 8b's weight compares with the average, max and min weights in its class.

Weight
All Subwoofer Speakers
KEF KUBE 8b
Min
Average
Max
Weight
Subwoofer Speakers under $750
KEF KUBE 8b
Min
Average
Max

Cabinet type and Materials

KEF KUBE 8b has a Acoustic Suspension type cabinet. Acoustic suspension aka Sealed subwoofers are preferred for music oriented systems whereas the Ported subwoofers are generally accepted to be more suitable for home theatre systems.

Port Position

KEF KUBE 8b is a front-firing port speaker , which gives you more flexibility compared to rear firing speakers when you need to place it close against a wall or other surfaces.

What's in the Box of KEF KUBE 8b?

Here are the items that are included inside the box of KUBE 8b:
  • Powered subwoofer
  • 6.5-feet AC power cord
  • Speaker-level input block
  • User Manual
  • Important Safety Information
  • Warranty Information
  • Warranty

    2 Years of parts warranty and 2 Years of labor warranty is generally provided by the manufacturer.

    KEF KUBE 8b  Lifestyle
    KEF KUBE 8b Lifestyle

    KEF KUBE 8b Alternatives in Powered Subwoofer Speakers
    Model Frequency Woofer Amp Power Dimensions
    Klipsch R-121SW
    Compare
    28-120k Hz 12" 200 watts 16-5/8inch x 16inch x 20-15/16inch "
    Polk Monitor XT12
    Compare
    24-160k Hz 12" 50 watts 16-7/16inch x 16-1/16inch x 19-1/16inch "
    B&W DB4S
    Compare
    10-350k Hz 10" 1000 watts 14-3/4 x 14-1/4 x 17-1/16inch"
    SVS SB-1000 Pro
    Compare
    20-270k Hz 12" 325 watts 13-1/2inch x 13inch x 15-13/16inch "
    Klipsch R-101SW
    Compare
    30-160k Hz 10" 150 watts 14-9/16inch x 14-1/16inch x 20-13/16inch "
    KEF KC62
    Compare
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    Wharfedale SW-15
    Compare
    30-120k Hz 15" 400 watts 22-7/16inch x 19-3/8inch x 24-3/16inch "
    Klipsch R-100SW
    Compare
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    Klipsch SPL-100
    Compare
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    SVS PB-1000 Pro
    Compare
    17-260k Hz 12" 325 watts 18-13/16inch x 15inch x 20-15/16inch "
    SVS PB-1000
    Compare
    19-270k Hz 10" 300 watts 18-7/8 x 15 x 20-15/16inch"
    Jamo S 808 SUB
    Compare
    39-180k Hz 8" 50 watts 18-1/16 x 7 x 14inch"
    KEF KUBE 10b
    Compare
    24-140k Hz 10" 300 watts 14-5/8 x 14 x 15-5/8inch"
    Cambridge Audio Minx X201
    Compare
    36-200k Hz 6.5" 200 watts 8-5/8 x 8-1/4 x 10-1/16inch"
    Klipsch SPL-120
    Compare
    24-125k Hz 12" 300 watts 17-11/16 x 14-3/4 x 21-1/4inch"
    Klipsch R-112SW
    Compare
    24-125k Hz 12" 300 watts 17-3/8 x 15-3/8 x 20-15/16inch"
    Frequently Asked Questions about KEF KUBE 8b
    What is the External Dimensions of KEF KUBE 8b


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