Tekton Double Impact & Comb Filtering


Like many of you, I have been pondering purchasing these speakers but am very curious about the unusual tweeter array. I asked the smartest speaker person that I know (he is a student of Sean Olive) about the design and below is what he had to say.   

"In theory it could work, but the driver spacing means that the crossover point would need to be very low.
He is using the SB acoustics tweeter which is 72mm in diameter, center to center on the outside opposing drivers is around 5.7 inches, which is about 2400Hz. This means that combing would stop between 1/4 to 1/2 of the wavelength (between 1200-600Hz) is where the outside tweeters should start playing nice with each other.
Since he is not using low enough crossover points he has created a comb filtering monster. Now while it's not the great point source that was promised, it's no worse than most line arrays and the combing will average itself out given enough listening distance.

The MTM spacing on the other hand is ridiculous. Hopefully he is cutting the top end off on one of those midrange drivers to avoid combing."

seanheis1
Oh, wow, this is so true, I mean, B&W, Magico and Martin Logan all publish FR graphs !!! << face-palm >>

No, no they don’t. It is not common practice at all. What is with this continuing onslaught of FUD not to mention double standards being pushed for this brand? Sheesh.

Best,

E
John Atkinson did publish Tekton Measurements, this was the Enzo XL a few years back. I'd say we passed his tests and John had overall good things to say about the Enzo XL. And KEY to this dubious thread is no-comb-filtering reflected in John's measurements.  

Eric Alexander - audio designer

Once again, and for the record... why I choose to not publish measurements:

"I've discerned over the years, the biggest gripe the critical types have with me is my decision to not publish measurements and/or extremely detailed loudspeaker specs. This really sends the tweakers into orbit! I design and build 'audio engine's'. Roger Penski, an internal combustion racing engine master said: "If you say anything to anyone, it's like cutting your paycheck in half." I appreciate his sentiment and wisdom."

Eric Alexander - audio designer
I rather agree with Eric.

Also, this BS phase / comb filter issue is easy to test two ways

1. Play music. Sit in sweet spot. Stand up. Sound weird? No? No problem.

2. Play music. Walk across the sound field. Sound weird? No? Then no problem.

The basic FR measurements would not cover this. Off-axis measurements would, and all speakers have some of this. However had Eric really flubbed the tweeter array, it would be absolutely obvious to any listener. This isn't a hidden attribute only the best listeners could hear. ANYONE could hear it if present.

Best,

E
Two Erics agreeing, there must be some kind of good karma wrapped up in that. :)

As to the statement that no measurements are published, there are several published on each Tekton model, save one. Hey Eric, publish what you want, it’s your company. The Enzo XL, which Stereophile measured, went up to 6 decibels to the plus and minus, which adds up to a 12 decibel swing.

So one thing can be certainly said, those speakers will color the sound, and change the music from what the artist intended. And since Tekton withholds this spec from every single model, one can assume that all of their speakers color the sound. Not my cup of tea.

PS: B&W do indeed publish the frequency response, which is what I’m referring to. frequency range with - or + decibel range. So then I looked at the Martin Logan site. Same thing, they include the decibel range, not sure what point you’re trying to make, Eric S.