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Discussion Starter #21
GregBe said:
...I think especially if you cross the speakers over at 80hz there is not much going on with a typical port anyway...
That crossed my mind as I was looking at frequency graphs last week.

For example I was considering the Epos M5. The graph from Stereophile is below. The port tuning frequency is at 52 Hz. The output at that frequency with a 12dB/octave crossover should be down about 7.5 dB. I agree with you that its worth giving it a chance anyway.

 

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Did you ever find the monitors you were looking for? I am looking also and would appreciate any input. I listened to a set of Triads and some M&K's, and I can honestly say that for HT the M&K's really hit the mark. It was the s-150 model I listened to. I actually put a thread on this forum to see if there was a way to build them. I think they are around $1,200 a pair, but wow. I mean WOW. I need to take the wife and trial them again and listen to 4 or 5 others around the same $ range or lower. My wife reeally liked them as well. Our past experience has been all with towers: B&W, Klipsh, Polk.
Roly
 

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Discussion Starter #23
I ended up buying floorstanders. I had to listen to a lot of floorstanders to find something I really liked. But I fell in love with and bought the DALI IKON 6. I did have a listen to the IKON 2s (bookshelf) while I was there and they were a perfect sonic match. I'll go back for the matching center one of these days.

I'm like many hobbyists who have living room systems. My priorites include a musical stereo set-up. The balance of the surround system supplements the stereo for surround movie listening. The cross over designs and speakers may not match perfectly, but its pretty close and stereo sounds great.

The M&K THX speakers have a great advantage: they are engineered to work perfectly together with their subs and the electronics to produce an accurate system. If I were in the market to put an all Theater system together from scratch (dedicated Theater room some day?) the M&Ks would be at the top of my list to audition.
 

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Discussion Starter #25
No, I have not. Below might be why:

Ultimate AV said:
For the 150 series, Kreisel designed what he calls a Phase Focused Crossover, which takes a three-dimensional approach to designing the circuit. "Normally, when you design a crossover, you pick a point in space, put your measurement device there, and design to produce optimum results at that spot. One of THX's specifications concerns horizontal symmetry: on one hand they want the speaker to be directional vertically—which produces lobing—but on the other hand, they want it to be very symmetrical in the horizontal plane, which means no lobing. To achieve that goal required the development of the Phase Focused Crossover. Other THX speakers usually have a tweeter and woofer arrayed vertically—that's almost the only way to get smooth horizontal directional characteristics.

"We developed our Phase Focused Crossover with multiple microphones and a time-based computational measurement system—[DRA Labs'] MLSSA, [Maximum Length Sequence Susyem Analyzer]—and that development has shocked most people in the industry—people can't believe that we got rid of lobing in the horizontal plane.

"It takes hundreds and hundreds of measurements and calculations to make it work—I'm not about to say too much and give away the secret. Most crossovers optimize the phase and amplitude characteristics of the driver to one specific point in space. Move off-axis—get closer to the midrange driver and farther away from the tweeter—and the phase characteristics of those two drivers have changed and the crossover is no longer optimized for that new point in space. The Phase Focused Crossover looks at the phase and amplitude characteristics of the drivers at many, many points in space and optimizes them to eliminate the dips and peaks in response. These are time-domain measurements, not frequency response. We did this work attempting to design a successful center channel, but found that it carried over to all of the front speakers."
 

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Hmm,
I guess I knew something about this. I talked with Barry Ober at M&K extensively after listening to a pair and he talked a lot about the lobing. I kind of understand the concept but will have to research it more to understand it. I am surprised though that one of the tech-heads on a forum hasn't decided to take on a challenge like this. Could be history in the making.
Roly
 
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