KEF THX Loudspeaker System Manufacturer's Comment
Editor: Thank you very much for the kind comments you made in your review of the KEF Home THX system. Words like "these are great Home Theater speakers..." are welcome indeed. Though you didn't find our Home THX system to be as good at music as, say, the ATC monitors or the Dunlavy SC-VIs, I find your comments about what the KEF THX system was primarily intended to do quite fair. So after saying my thanks, as it were, I would like to comment on a few things.
First, I'm sorry we confused you with the markings of the "Blend" control on the AV1 subwoofer amplifier. It is indeed a phase control, and it operates only in the Conventional Stereo mode. Between the + and the symbols are 180° of phase adjustment. Because the control's effect upon absolute phase depends on the setting of the crossover frequency, we chose not to label it with 0° and 180°, which would imply something that is not strictly true.
Second, JA's measurements are worth a second look. I've enclosed curves taken from our measurements of the systems we sent you for review (like KEF Reference Series systems, we measure every Home THX system and maintain the data in archives). JA suggests that the 86dB sensitivity he "calculated" may have been lower than our published 90dB due to differences in measurement technique. As you know, we have some small experience in measuring loudspeakers, and you can see from the curves why we're sticking with our published spec.
I also see that JA didn't measure the AV2 surround speakers because "there are no agreed-upon standards for surround-speaker performance." THX has some rather specific requirements for certifying surrounds, yet within those standards subtlety of execution counts for a great deal. Perhaps the people at THX would let you in on their specs. It could be a very valuable measurement for your readers.
Third, since you brought up the infamous Home Theater Technology review, I'd like to set the record straight. KEF did not "rework a product in response to a bad review." On the contrary, we had begun a revision of our AV3 several months before our US distributor submitted the product for review. The decision to revise the system was the result of discussions with distributors, dealers, and end-users from around the world. The original treble balance had an upward tilt rising to 2dB at 18kHz, and sounded very good in many installations. But in too many rooms it sounded overly bright. After extensive listening in different rooms, we decided to make the treble balance flat.
When we were informed that HTT was about to write a scathing review of the KEF THX system, we suggested they listen to the revised AV3, which was just coming into pre-production. We thought it would at least be useful if the systems they heard were the same as those that would be in the stores at the time the review came out.
We sent out pre-production systems for review, but apparently the HTT staff saw our offer as some sort of scam. Oh well. They listened to the revised AV3s then wrote their scathing review. I understand it's called "tell it like it is" journalism. Hmmm.
When your review system was "slightly delayed," we weren't in the car park smashing speakers (although the image is delightful); nor had we "gone back to the drawing board for a few last-minute modifications." Instead, we were setting new test specs for the computers on the production line, verifying reference crossovers and systems, and doing all the other work we do when we move from pre-production to full production.
The reason you didn't get the "speakers that got panned" is that they were no longer available. Our decision to revise the AV3 was a formal decision. The previous balance was deemed "not current" and was "not for sale." We try hard, at KEF, to be cooperative. But we're not casual about issues like this. I hope you understand.
I'm sorry you "approached these speakers with some misgivings," in that those misgivings appear to be founded on misunderstandings. Perhaps if it had been otherwise you would have commented on the KEF Home THX system's dialog clarity, the timbral matching of surrounds to LCRs, or the system's ability to resolve complex detail in soundtracks. These are the qualities of "great Home Theater speakers."Raymond J. Lepper, Managing Director, KEF Audio Ltd.