Kef Kube equalizer

Get a Behringer DEQ2496 equalizer. It will automatically make your KEF speakers flat, so you won't need to figure out what the original KEF equalizer did.

A room correction device is an excellent idea. Typically the oem bass boost eq's provided bass boost to compensate for the natural roll off of the enclosure type, e.g. infinite baffle 12dB, reflex loaded 24dB. The advantage of using such an eq, is that it allows the manufacturer to use a smaller loud speaker to get the same bass output of a larger loud speaker. Advantages: (i)use less expensive smaller drivers, smaller drivers are more linear and typically have less energy storage,(ii) smaller drivers permit the use of smaller cabinets, smaller cabinets have better marketing potential, use less materials, need less bracing, weight less, cost less to ship and store.All of which reduce costs. Disadvantages, (i) puts more burden on the amplifier, so amplifier power needs to be greater/more robust and that usually means more expense. (ii) depending on how it's inserted in a given system, requires at least 1 and possibly 2 extra sets of interconnects (iii) Many audiophiles object to any extra circuitry in the audio signal, and eq's (rightly or wrongly) are particularly viewed with suspicion, (iv) it's been my experience that there are some limitations to ultimate volume levels compared to larger (usually much larger) speakers that don't use such a device that are capable of the same bass output.
As the bass roll off is based upon what would happen in an anechoic environment, it doesn't correct for the varying bass responses typically experienced by most real world users. The digital room correction devices that are now available and weren't commercially available when most of these speakers were being devised can now boost, not boost, and/or even attenuate for ones actual room. As these speakers were originally built to meet the demands of extra boost, they may be better equipped to to work with these devices than speakers that aren't so designed.
I'm surprised that with the current digital technology available and the increased use of surround sound, where having many large speakers could become problematic, that this concept hasn't found much new life.

Unsound... Bose was one of the first to use the equalizer aproach. The idea was to avoid trying to achieve smooth response below driver resonance, which is almost impossible. Most speaker designers try to push resonance down by driver design and large enclosures. Prof Bose figured out that roll off below resonance, while steep, is inherently very smooth and therefore correctable by electronic equalization. He pushed resonance up to more than 200 Hz.

Eldartford, I suspect that like most things Bose, the EQ Bose used, might have been used a little differently than the way B&W, ICT, KEF, Thiel, etc. were using their EQ's.

Hi Unsound

Thank you for the detailed response and the suggestions. I've reached out to KEF America to see what they say regarding the KUBE and other alternatives for the 103/3s. I'm also looking for older KEF KUBE EQs and those other manufacturers you mention. I think though with my KEF speakers there was a specific KUBE EQ that was made exactly for it. I saw a KEF KUBE for a 102/2 as well as a KEF KUBE 200 but I don't think those will work with my speakers.

I was hoping an older cheaper Hafler EQ I found locally or an SAE Mark 1 XB could do the job but to get optimum sound quality from the 103/3s I think I have to set my sights higher.

Eldartford

Thanks for chiming in as well. I had seen the DEQ2496 used before in other applications but didn't think it would work for my KEF 103/3 speakers. I'll keep an eye out for one used. New it is over $300 and bit over what I had wanted to spend. I read in another thread I may be able to handle the bass issues I'm having my getting a sub and crossing it over where the 103/3s roll off. The thing is that I don't know what the exact roll off point is on the 103/3s.

Well again thank you both and I have some thinking and searching to do. The help is appreciated.