KEF 107.2 with KUBE?

Hi I owned these speakers a few years ago. They sound fine without the Kube but are definitely more accurate with the KUBE. Unfortunately each Kube is adjusted for the particular drivers and individual speaker - left and right. In other words each Kube is specific to each actual box. Variations in the actual drivers installed are adjusted for in the Kube. Therefore you cannot mix Kubes and speakers or buy another Kube. So in summary without Kube is ok but you should discount the value or price heavily as the speakers are not complete and the Kube cannot be replaced.

I've read that the design of the KUBEs is specific to models of speakers. The installation instructions for the KEF 107.2 warns that a 107.2 KUBE should be used with 107.2 speakers, but does not mention that KUBEs are adjusted for individual speakers. If that were true, a KUBE would need to be readjusted any time a driver is replaced, reconed, or received new surrounds. The 107.2s I'm buying are said to have had the cones and surrounds replaced recently -- before the seller became enamored with ultra-low wattage amps that require even more efficient speakers.

db

Hi db

Contacting members is no longer an option since the Audiogon upgrade took place. I saw 2 active listings for KEF 107.2 speakers. You can ask those sellers questions about the 107/2 and the Kube equalizer.

I never saw KEF say their KUBE Equalizers were adjusted for individual speakers I only saw different KUBE EQs for various speaker models. 105/3, 104/2, 103/3 etc etc. Have you tried contacting KEF about the 107/2 and the Kube EQ for it? I've spoken to Corey Medley over at KEF customer service (GP Acoustics (US) Ltd) a couple of times regarding various KEF speakers I've owned or had questions about and they were responsive.

Also I don't see how the KEF Kube EQs would need to be re-calibrated if a re-foam or surround repair was done. Wouldn't that kind of repair return the speakers to original form so no change to the eq is warranted? I would think if you changed the original drivers to an entirely different speaker you would have to modify the Kube.

Well good luck in your search.

J24,

Recalibrating KUBEs when a driver is altered would be necessary only if KUBEs were calibrated for individual speakers, something neither of us thinks is likely.

db

KUBE -
I AM ABSOLUTELY CORRECT WHEN I SAY THAT EACH KUBE IS CALIBRATED TO THE INDIVIDUAL SPEAKER.
If you can find Dick Olshers review in Stereophile vol 9 no 7, November 1986, he discusses the 107 Kube. He actually had DC offset problems with his 107's Kube.
When contacting the factory Dick was advised that the factory had all the Kube parameters recorded for his specific speakers, which were serial number SN1407, and the factory would be able to build a new Kube for those specific speakers. Each speaker is also marked L for Left and R for Right. This is all documented in the review.
I can only suggest if you still dont believe me, or Dick Olsher, then contact the factory direct and hope that someone there has been there long enough to remember.

06-04-12: Dover
...
If you can find Dick Olshers review in Stereophile vol 9 no 7, November 1986, he discusses the 107 Kube. He actually had DC offset problems with his 107's Kube.

Here is Olsher's review in Stereophile

I reread Olsher's review of the 107 in Stereophile. I think I discounted that aspect of it because I suspect hyperbole. Is it logical that contemporaneously built speakers would have such variations, yet the factory could build a given speaker with such precision to match exactly a previously built speaker? If that were so, why then would there be the supposed variation? And lest we forget, those KUBEs have HF and LF gain controls aimed at tailoring the sound to particular placements and room acoustics.

But if I read the review literally, I should be able to send KEF the serial numbers of my 107.2s and get a KUBE made for them. Unfortunately. my 107.2s, like so many others, were reconed with new surrounds in the US. Woe is me!

db

I have a pair of KEF 107s and tried them with and without the KUBE in a blind test and my ears could not tell the difference when it was in and when it was out of the circuit. So when asked if I wanted to sell it, I did.

My KEF's are in LN condition and so far these 20+ year old speakers show no sign of needing the woofers refoamed, but then I haven't moved them for the last 20!!

The Kube makes a noticeable difference with bass. If you are so discerning that you could tell the difference between different Kubes built for 107's you should not buy 107's.

I am the original owner of a very early pair of 103/3s that have always been used with the Kube that came with it. The installation manual makes no mention of the speakers and the Kube being matched but the Kube is labeled on the rear for 103/3. In the 25+years I've had them I don't think the dial has been off the 12 o'clock position a dozen times.
"The Kube is an active low-level equalizer. This equalization forms part of the speakers crossover network and is an essential part of the design."(from the manual)
I would be more concerned with the condition of the drivers-both the woofers and tweeters. Great restoration threads on 107/2s on AK.These were expensive when new and bring big money today.Good luck and happy listening.

There are much better speakers out there now.

All kef reference of that time were matched pairs, if memory serves they were within 1/2 db pairs and 1 db of the standard. the kube was made for models NOT INDIVIDUAL PAIRS. the first kube for the 107 was complex, the later kube's were more user friendly and the 107/2 kube was different than the kube 200 and 100. I just bought a pair of 107/2's and initially forgot to install the kube and must say if you can't hear the difference you really wasted a lot of money. some kef R of that period offered the kube to add deep bass, but the 107 and 107/2 were designed with it.

I understand there were some 107/2 KUBEs with balance XLR connections.  I'd pay $1K for one of those.