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KEF KC92 and Kube MIE subwoofers

ban25 said:
Yes I'm using both in a dual sub configuration.
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Sorry that i ask you again. But i bought a KF92 as 3rd Sub. I messuret a sweep and than only a 20hz tone but it didn t make any different in spl. But with a 25hz for example i get more spl round about 5db agains a sweap. But in the kc92 review he was able to get more spl at 20hz. As you have both subs can i ask you to check it please?
 
www.stereophile.com

KEF KC92 powered subwoofer

I was fascinated by Herb Reichert's adventures with the KEF KC62 subwoofer, so I borrowed one. Beautifully engineered, contoured, and finished and chock-full of cutting-edge technology, it would be welcome in any room and easily integrated into any system. However, it struck me as not just small...
www.stereophile.com www.stereophile.com
 
What a nonsense:

“Still, the KC92 is very small compared to the huge subwoofers that are common in home theater systems, yet KEF claims a response down to 11Hz and a maximum SPL of 110dB! How? The KC92's "Music Integrity Engine" is a suite of custom DSP algorithms including "Intelligent Bass Extension" (iBX) to monitor signal level and content to modulate output level and frequency response so that the KC92 can play "louder and remain dynamic at any listening level." So KEF does acknowledge that "Hofmann's Iron Law" (footnote 1) can't be broken, but that they are, in effect, bending it.”

No way this subwoofer reaches 110db @ 11hz.
 
Puddingbuks said:
No way this subwoofer reaches 110db @ 11hz.
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Which they don't claim but give both data separately, one of the advantages (also for marketing) of such DSP controlled loudspeakers.
 
thewas said:
Which they don't claim but give both data separately, one of the advantages (also for marketing) of such DSP controlled loudspeakers.
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Yes not at the same time of course :) it can do 11hz at some puny level and 110dB at at much higher frequency ? Have someone done proper measurements ( Erin ? ) maybe it can be deduced from there ?
 
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Mnyb said:
Yes not at the same time of course :) it con do 11hz at some puny level and 110dB at at much higher frequency ? Have someone done proper measurements ( Erin ? ) maybe it cannbe deduced from there ?
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The only measurements I know is a in-room one with some Monitor Audio Silver floorstanders from Sound & Vision

1735839510988.png

source: https://www.soundandvision.com/content/kef-kc92-subwoofer-review

and some anechoic and in-room from Australian Hi-Fi, exemplary few of them:
1735839729458.png

1735839745398.png

1735839762421.png

Souce and more: https://www.whathifi.com/reviews/kef-kf92
 
thewas said:
Which they don't claim but give both data separately, one of the advantages (also for marketing) of such DSP controlled loudspeakers.
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Point is that the text suggests it can hit 11hz @110db.
 
Erin’s measurements of the KF92, older model than the KC92:

IMG_1955.jpeg


IMG_1954.jpeg



Only 85db @20hz. And watch it drop, dsp limited, below 40hz.

Distortion also is not great, so this is a small subwoofer first, sound and output come second. My monoprice monolith 15 can do 110db @20hz for comparison, that is a staggering 25db difference.
 
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Puddingbuks said:
Distortion also is not great, so this is a small subwoofer first, sound and output come second. My monoprice monolith 15 can do 110db @20hz for comparison, that is a staggering 25db difference.
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I assume your subwoofer is also slightly larger? :)
 
I personally think that the only thing wrong with the KEF is the price. Otherwise, it seems like a pretty nifty engineering given the size and sure makes a lots of people not able to accommodate larger subs quite happy.

For the ones with limited budget, SVS Micro 3000 is also a solid solution.
 
I think people should be more realistic. Designing a subwoofer involves an inevitable trilemma: you cannot have low price, small size and power/extension all at once. For many here power and extension are their first concern, and these subwoofers are not for them. Monoprice may well be their best option. For many other consumers small size and good looks matter more, particularly when using multiple subs. Small size combined with decent performance requires different and more expensive technologies, such as big amplifier power and dual opposed drivers. You really cannot have it all. Therefore, both Kef and B&W have two lines: their expensive smart looking and relatively small dual opposed models, and their their cheaper more basic and relatively larger models with one larger driver and smaller amplifiers that are possible because larger boxes make for a more efficient speaker (the B&W ASW line and the KEF Kube line). It is horses for courses. As for KEF, their Kube series performs pretty well, given the measurements of the Kube 10b in the ASR subwoofer database, and typically have a somewhat flatter response than e.g. SVS SB models. The KEF Kube series is priced quite competitively here in the Netherlands, and in my view is also smarter looking than comparable SVS models. However, the balance may be different in other markets.
 
Oddball said:
I personally think that the only thing wrong with the KEF is the price. Otherwise, it seems like a pretty nifty engineering given the size and sure makes a lots of people not able to accommodate larger subs quite happy.

For the ones with limited budget, SVS Micro 3000 is also a solid solution.
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Yes i have two of them for music , but i got them in a packet deal with my LS60 .

They are perfectly fine for what they are. Works very well for a music only system at mid volumes in medium sized/small room

The price are such as i would have considered something else otherwise if i had not gor a good price on them .

Imho half the price and 3dB more output would move them into the upper end of competitive prices .

The design is nice :) many subs looks terrible in room in person if you have something akin to nice furniture. At my current age when i dont have thrift store second hand furniture as when I was a student, design matters
 
Puddingbuks said:
Strange combo, a 15 inch woofer with only a 300 watts amp (Kube 15 MIE).
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Generally the larger the subwoofer the less EQ is needed to try and achieve decent LF extension. Also larger drivers tend to be more efficient.

While you might need a 1000-1500w amp in a small 8" or 10" sub to achieve sub frequencies, a 15" driver in a larger box might get by with far less power.

Every 3dB of boosting EQ requires twice as much power on hand and in some small subs upwards of 14 dB of boost is being used, maybe more (although I haven't measured it, I don't tend to mess around with small subwoofers as they're a bit of a waste of time IMO).
 
574stereo said:
Generally the larger the subwoofer the less EQ is needed to try and achieve decent LF extension. Also larger drivers tend to be more efficient.

While you might need a 1000-1500w amp in a small 8" or 10" sub to achieve sub frequencies, a 15" driver in a larger box might get by with far less power.

Every 3dB of boosting EQ requires twice as much power on hand and in some small subs upwards of 14 dB of boost is being used, maybe more (although I haven't measured it, I don't tend to mess around with small subwoofers as they're a bit of a waste of time IMO).
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+1 a large driver in a large box is much more effective :) if you also have a bass rellex design its even more effective .

The size tradeoff can be noted in my system and the fact that i also wanted closed boxes ( no bass rellex ) my closed box LS60 has 500+100+100 watts per speaker and each KC92 sub 1000w so system peak power is 3400w ?

Normally enough to power a small club/bar with efficient PA speakers, but I listen to Jazz at the pawnshop :D

Small closed boxes with small drivers are power hungry.
 
Mnyb said:
Yes i have two of them for music , but i got them in a packet deal with my LS60 .

They are perfectly fine for what they are. Works very well for a music only system at mid volumes in medium sized/small room

The price are such as i would have considered something else otherwise if i had not gor a good price on them .

Imho half the price and 3dB more output would move them into the upper end of competitive prices .

The design is nice :) many subs looks terrible in room in person if you have something akin to nice furniture. At my current age when i dont have thrift store second hand furniture as when I was a student, design matters
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I agree: looks matter if your furniture is similarly elegant (I have furniture by the likes of Poul Kjaerholm and Arne Jacobsen).
 
permission to ask a dumb question: KC92x2 vs KC62x4?

current system: LS60 and KC62x2.

room: 14ft x 14ft x 9ft, opening on the right side. pictures of room

current satisfaction with system: very high, favorite system i've ever owned.

why i'm considering more/different subs: more bass volume in the 30hz - 60hz range, specifically for space bass/experimental bass. i don't NEED more, i just think it would be fun.

"well you should consider a Monolith/Rhythmik/<other large 125lb black box>": you are right, and thank you for suggesting the best value for my money, i sincerely appreciate it, but i really love the way KEF looks. i've come to the realization that, similar to how we "eat" food with our eyes before our mouths, i "listen" to music with my eyes before it hits my ears. just looking at my speakers and subs makes me happy. probably more importantly i'm 43 years old and my back kind of sucks, so my days of lugging around 100lb+ subwoofers are over.

"well then KC92 is the obvious choice, Erin's testing shows it is significantly louder than the KC62, especially in the lower bass regions": you are right again, selling the KC62s and buying two KC92s is likely the best move, but I'm considering buying two additional KC62s instead purely because of the way they visually match the LS60s. also white KC62 refurbs are more readily available at A4L, the KC92s sometimes are in stock but not frequently.

"got it, what DSP are you using?": no DSP, i'm sorry. i'm not opposed to it i just don't have any. and at least to my ears there really isn't anything missing from this system. i could buy no new subs and be perfectly content, really this is just for fun, but isn't all of this hobby just for fun?

"ok then, can you show us some measurements of your in room response?": no i'm sorry, i don't own a measurement mic. i know i need to get one and learn REW, again i'm sorry.

i guess my question is i don't know how to do the decibel math. i know per Erin's comparison of the two subs (well he compared the KC62 to the KF92, which is essentially the same as the KC92) the 92 can be anywhere from 5-7db louder in the 30hz - 60hz range, which is significant. would adding two more KC62s be 5-7db louder in that range?

having four subs would also allow me play with placement, like having a sub in each corner. or i could just stack them (like in this picture here). I tried it in one corner and seemed to be fine, since the subs don't vibrate i believe it should be stable.

thanks in advance for any replies, happy to hear anyone's opinions, experience, insults, etc. :)
 
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