Beyma 12P80ND + TPL-150

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#342
1ogic said:
I tested 12p80nd in OB setting on a La Scala bassbin and a CP25 Beyma tweeter. actually it's a La Scala speaker upgraded with CP25 tweets (very smooth sounding tweeter). I replaced K-55 - K-400 horn of Scala with 12p80ND and set some attenuation for woofer and tweeter. the result was a much better-sounding speaker with no honkiness coloration in mid-range area which K-400 is pretty high on that. but you know what, La Scala is a folded horn which doesn't go that low in bass, it goes as low as ~50hz. 50hz is bass-shy to me, music needs more low frequency to be heard full body. the woofer I'm using in LS is CW1526 15" from Bob Crites originally made by Eminence.
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I have the K55 and I think the honkiness is because of the phase-plug and the very thick phenolic diaphragm. The Yamaha JA-6603 has a much thinner phenolic diaphragm with a very nice sonding phaseplug and it sounds much better. Still a little honky, and this is why I prefer the same driver but with an aluminum diaphragm. Beyma CP25 has alu too but it has such a small diaphragm that I would not use it lower than 2kHz, and not higher than 12kHz.
 
#353
Two questions about the TPL-150H + 12P80Nd combo:

1. Has anybody actually measured these (off-axis) to see what is the optimal crossover frequency with respect to directivity and power response?

2. What would be the minimum listening distance for satisfactory driver integration if the center-to-center spacing between the drivers is 280mm on a flat vertical baffel and the ear is exactly on-axis with the tweeter?
 
#354
Not the 12P80Nd, but a MTM with a TPL-150H and two AE TD-12M.

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Yes, there is some narrowing, but TBH, the TPL sounded strained crossed lower than 2K with a LR2 slope. Crossing lower will need much steeper slopes, which passively isn't very practical IMO.
 
#356
That strain is most likely caused by IM, the byproduct of over excursion. Notably Lynn Olson has defined such action and requires a 3rd order (or higher) network to prevent. Should search Jean-michel Le C'leach has a spreadsheet for calculating a BW3 with offset crossover points to derrive a -5dB notch and then proper physical alignment offsets to put everything back in phase. Shouldn't be too difficult to make passive. 🙂

Active is so much easier. I'm working on an mtmww mltl using 6.5"s and an AMT tightly wedged in between. Cross is 2.1k LR4
 
#357
So at xo fq 1.6kHz and 280mm c2c spacing, what is the formula for calculating minimum listening distance for full driver integration...?

EDIT: Btw 280mm minimum c2c is bad enough as 1 wavelength is 1,225 Hz, a counter argument against highisher xo...
 
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#358
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#359
I'm still struggling with my TPL and 12P80ND-V2 setup and whole thing sound like the real thing but the only issue is about midrange narrow dispersion. I've tried a dozen of smaller drivers (Faital Pro 10PR410 and 8PR150 and B&C 8NW51) but 12P80ND-V2 sounds the best to my ear when I sit on sweep spot. I was wondering maybe is will be possible to enhance it's directivity by adding some kind of waveguide or horn? any idea?
 
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