KEF Kube 8b
Subwoofers
This KEF’s Kube 8b review is not your standard review. We have published many pages about subwoofers and how to set them up correctly. Yet our readers ask the same basic questions again and again – therefore I will share some practical experience from my Kube 8b’s auditioning.
Function and form
The KEF Kube 8b is one of the smallest and most beautiful subwoofers I have reviewed so far. Forget about the internet images, nothing will prepare you for how cute this 30cm cube is. The top black glass plate is surrounded by a fabric from all sides. The rear control panel is embedded into it. There is a 200mm bass driver in the Kube 8b’s cabinet but the driver cannot be seen as the fabric cannot be removed. The subwoofer is powered by a 500W Class D amplifier and provides 105dB of acoustic pressure – enough for small and mid-sized rooms. The control panel provides phase setting (switchable between 0 and 180°), volume control and low pass filter setting (40-180Hz). KEF included also a simple DSP processor that will help you optimize the subwoofer for placement – in room, corner or cabinet. Don’t be afraid to experiment as actually you may find that cabinet voicing is the best for you while the sub is actually not in any cabinet. The good thing is that the Kube 8b can be connected via loudspeaker cable to amplifier or speakers. The power inlet is of IEC C8 type so no use for aftermarket high end cords here. Everything is clean and well thought.
Bass management
The problem of good bass is not a problem of a subwoofer, rather it is a problem of a room. In my room I hear less bass at 50Hz point which is a result of room modes. The only thing I can do about it is to move my listening chair. This solves the problem but creates another problems at different frequencies. Anyway, I tried to tackle the issue with the KEF.
I placed the Kube 8b into my listening position at the ear’s height and then crawl around the room to find out the spot where the bass drop fills in. When such a spot was found I moved the sub over there and set it up by ears. How to do this is described in detail in our articles.
Clarity & delicacy
No matter that everything was technically correct the 50Hz fill in did not contributed to what I heard so much I expected. But the low rumble filled in the whole house. I ran with a handheld decibel meter around the house and in some rooms I measured up 110dB of acoustic pressure – which is a good rock concert volume.
What I want to say is that the temptation to fill in narrow band fluctuations with a subwoofer don’t have to be necessarily appreciated by other members of your family or by your neighbours.
Tonal accuracy
The KEF Kube 8b is a good subwoofer, nothing less nothing more. Up to ca 25m2 it will be a good companion for stand-mounted speakers or for bookshelf monitors. It looks nice which counts a lot as most subwoofers are just big black ugly boxes. When critically auditioned it reliable added the bottom octave to Steinway grand piano even with floorstanding speakers and complemented their ambience. Without it the music breathed less.
Spatial resolution
One final remark. The fabric is quite thick and tight and at certain frequencies it creates a kind of secondary membrane in front of the driver. When I played loud bass heavy music I could hear the fabric resonate. This was audible with sustained signals like synthesizers or organ and did not appear in transient programmes like kick drum or electric bass. It is also possible that only the reviewed piece was doing so.
Recommended resellers
Perfect Sound Group, Praha, tel. +420 722 960 690
Manufacturer's website: http://www.kef.com
Associated components
- Sources: Accuphase DP-720, Accuphase DG-58
- Amplifiers: TAD-M2500 MkII
- Interconnects and speaker cables: Audioquest Vodka, Audioquest Redwood, Vovox Sonorus XL, Audioquest Wild
- Loudspeakers: TAD Evolution One E1, SVS SB-3000
- Power conditioning: Shunyata Research Sigma HC, Shunyata Research Denali 6000T, Nordost Valhalla, Synergistic Research Atmosphere Level 2
Gallery
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