Beyma 12P80ND + TPL-150

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Rewind

Rewind

Member
Joined 2009
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 the woofer I'm using in LS is CW1526 15" from Bob Crites originally made by Eminence.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.
 
N

NiToNi

Member
Joined 2004
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?
 
Face

Face

Member
Joined 2007
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.
 
Greebster

Greebster

Member
Joined 2010
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
 
N

NiToNi

Member
Joined 2004
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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tiefbassuebertr

tiefbassuebertr

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Joined 2005
tiefbassuebertragung.de
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dave123

dave123

Member
Joined 2004
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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