Test design subwoofers KEF Kube 8b, Kube 10b, Kube 12b

They were already announced in November 2017. The new subwoofers from KEF are now available in stores across the board. And contrary to common trends of dull cube optics, they are actually extremely chic, I think. The three variants are called KEF Kube 8b, Kube 10b, and Kube 12b and cost 550, 650, and 750 euros respectively. Test design subwoofers KEF Kube 8b

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My first encounter with a KEF subwoofer was in my good buddy Arne’s home theater, back in the 90’s, back in the days of laser discs and tube projectors. The fat THX subwoofer from the Reference series was so huge back then that it served as a coffee table in the cinema with a glass plate on top. The Kube cubes are far removed from this in terms of space, and price, but of course also in terms of performance.

design Test design subwoofers KEF Kube 8b

The design of the Kube series looks pleasantly organic compared to other bass cubes thanks to the rounded edges, the surrounding fabric covering, and the high-gloss cover with a subtle brand logo. Even with the dimensions, placement in the living room should not be a problem:

Kub 8b 293 x 293 x 310 mm (H x W x D), 11.3kg

Kub 10b 370 x 353 x 370 mm (H x W x D), 17.4kg

Kub 12b 410 x 393 x 410 mm (H x W x T), 20.6kg

The housing and the built-in woofers from our own production are the only distinguishing features of the three siblings. And as with most subwoofer types, the driver sizes are already hidden in the name. The Kube 8b uses an 8-inch (20cm) speaker, the Kube 10b uses a 10-inch (25cm) speaker, and the large Kube 12b uses a 12-inch (30cm) speaker accordingly. Rather unusual: all drivers work in a closed housing, so they do not use bass reflex support or anything similar to increase efficiency. This costs sound pressure, but in return, it brings control and precision to the reproduction.

KEF uses the same electronic module in all three models. It uses a DSP engine for filtering and a Class D power amplifier with 300 watts of continuous power. Thanks to its good efficiency, it does not need any cooling fins. The connection via “shaver power cable” does not necessarily suggest great performance. But how it really behaves remains to be seen.

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In addition to the usual cinch pair as an input, speaker cables can also be connected using the supplied plug-in terminal. In addition to the switchable phase position, there are also the usual controls for input sensitivity (volume) and upper limit frequency (crossover). This circuit, or its scale, can actually be taken seriously thanks to its digital structure; with analog variants, the set values ​​are usually only very approximate….

Clever: At the right stop, position LFE, the integrated filter is switched off. That’s a good thing so that you don’t get double filtering when using bass management in the receiver because it always goes for precision and can twist the phase response in an adventurous way, which makes coupling to the loudspeakers more difficult.

But the spatial filters simply labeled “EQ” are really clever. Depending on the setup, as the frequency falls, the lower register will inflate unintentionally. It depends on how many surfaces the sound is bouncing off: just the floor (switch set to In-Room), the floor and a wall (Wall/Cabinet), or a corner with two walls and the floor (Corner).

I couldn’t really understand the iBX, which was mentioned many times in the KEF catalog, but never really documented: the intelligent Bass eXtension. The marketing text suggests a level-dependent frequency response. In all measurements and listening tests, however, the three woofers behaved purely statically. The specifications for the maximum sound pressure of 105, 111, and even 114 decibels for the large model are more wishful thinking than realistically achievable with real music or film programs.

In the practical test, the KEF Kube showed its most pleasant side. Connection and installation were easy. Thanks to their digital filter and signal processing, the phase curve, for example, was almost linear, which is practically ideal for coupling to the loudspeakers and also offers the best conditions for automatic calibration systems to quickly achieve a seamless transition between woofer and boxes.

Thanks to the closed construction, the KEFs didn’t struggle with flow noise when things got loud. Only when the chassis reached its mechanical limit were there audible but comparatively harmless secondary components. The Kube 8b and Kube 10b showed themselves to be somewhat reserved in the deep bass, both when measured and when heard. This is definitely an advantage. Because the bass is not cut off but reduced.

All three models sounded nice and “fast” and dry, the bubbling bass of some inexpensive competitors is alien to them. But they are less suitable for level orgies. In the listening test, all three did a top job and, in combination with the Heco Celan GT 302 compact loudspeakers, provided the desired foundation and bass extension – depending on the subwoofer model – by one to one and a half octaves.

Conclusion: Chic and good bass for a small price

With the Kube series, KEF offers three really pleasant subwoofers, pleasantly inexpensive, pleasant on the eye and on the ear. Such harmoniously balanced parameters are rare. The clever local filters for quick tuning and easy-to-dose digital filters with analog controls allow precise adjustment to the speakers. Sounding dry but not harsh, they are best suited to compact speakers that play crisply. They are more musical woofers than home cinema effect shooters. Good this way.

The rating for all three is therefore 4.3 stars and “very good”. Because the larger woofers offer more depth, they each cost a hundred more. In this respect, the KEF Cube is a pleasantly inexpensive, finely spread offer for cost- and design-conscious music lovers.

Q1:What is the frequency response range of the KEF Kube 8b subwoofer?

Answer: The KEF Kube 8b subwoofer has a frequency response range of 38 Hz to 200 Hz, allowing it to produce deep bass sounds effectively.

Q2:What type of amplifier does the KEF Kube 8b use, and how does it benefit performance?

Answer: The KEF Kube 8b uses a 250W Class D amplifier, which provides efficient power delivery and minimal distortion, resulting in clean and dynamic bass output.

Q3:How does the KEF Kube 8b’s DSP (Digital Signal Processing) enhance its performance?

Answer: The DSP technology in the KEF Kube 8b allows for precise control of bass output, enabling users to customize settings such as crossover frequency and EQ. This helps optimize the subwoofer’s performance according to the room’s acoustics and personal listening preferences.

Q4:What are the connectivity options available on the KEF Kube 8b?

Answer: The KEF Kube 8b offers various connectivity options, including RCA line-level inputs, speaker-level inputs, and wireless connectivity for easy integration into both home theater and stereo systems.

Q5:What features contribute to the KEF Kube 8b’s ability to adapt to different room sizes and acoustic environments?

Answer: The KEF Kube 8b features adjustable phase control, variable crossover frequency, and an EQ setting that allows users to tailor the sound output to suit different room sizes and acoustics, ensuring optimal bass performance regardless of the environment.

Q6:How does the compact design of the KEF Kube 8b impact its usability in home audio setups?

Answer: The compact design of the KEF Kube 8b makes it easy to place in various locations without taking up much space. Its aesthetic appeal and versatility allow it to blend seamlessly with different room styles while still delivering powerful bass performance.

Q7:What user feedback was observed regarding the sound quality of the KEF Kube 8b during testing?

Answer: User feedback indicated that the KEF Kube 8b delivers rich, tight bass with excellent clarity. Many users noted that it provides a balanced sound that enhances both music and movie experiences without overwhelming the overall audio mix.

Specifications

1. Driver Configuration:
   • Type: 8-inch Uni-Q driver
   • Cone Material: Polypropylene or similar lightweight composite
2. Power Output:
   • Amplifier Type: Class D
   • RMS Power: 300 watts
   • Peak Power: 600 watts
3. Frequency Response:
   • Range: 24 Hz to 140 Hz
   • -6 dB Point: Approximately 24 Hz
4. Crossover Frequency:
   • Adjustable crossover range: 40 Hz to 140 Hz
5. Connectivity:
   • Inputs: RCA LFE, stereo line-in
   • Wireless option: Compatible with KEF’s wireless system
6. Dimensions:
   • Height: 305 mm (12 inches)
   • Width: 305 mm (12 inches)
   • Depth: 305 mm (12 inches)
   • Weight: Approximately 11 kg (24 lbs)
7. Enclosure Type:
   • Ported design for enhanced bass performance
   • Cabinet Material: MDF with a high-gloss finish
8. Controls:
   • Phase control switch (0°/180°)
   • Volume control knob
   • Auto-on/off feature
9. Color Options:
   • Black, white, or other finishes (depending on the model)
10. Additional Features:
    • DSP (Digital Signal Processing) for improved sound management
    • High-quality components for low distortion and improved sound quality

Test Design Considerations:

• Acoustic Testing: Measure frequency response in various room setups.
• Performance Testing: Evaluate the subwoofer’s output in different playback scenarios (music genres, movie effects).
• Integration Testing: Assess how well the subwoofer blends with various KEF speakers.
• User Experience: Consider ease of setup, controls, and overall design aesthetic.