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-   -   Which helper woofer in open baffle would you pick? (http://www.diyaudio.com/forums/full-range/179231-helper-woofer-open-baffle-would-you-pick.html)

Racket Scientist 16th December 2010 02:54 AM

Which helper woofer in open baffle would you pick?
 
I'd like to use a helper woofer with my Tang Band 1808 in a low, wide open baffle design. I've been looking at these two, partly because of the price and the high Qts: the GRS 12FP-8, and the Eminence Alpha 12A. I plan to crossover to the Tang Band at around 200 Hz using an active crossover. One downside to the GRS is the lower sensitivity - since I'll be using an active crossover its not as big an issue, but I'd like the option of later building a passive crossover to allow use of just one amp if desired, and the GRS would probably disappear in that event. I've about settled on the Alpha. Any other reasonably priced contenders I should consider, and do you agree that I should go with the Alpha?

Racket Scientist 16th December 2010 02:59 AM

The more I look at the GRS I realize I shouldn't have even bothered including it for consideration. Any other contenders for a 12" helper woofer below about $100 I should consider? I'm using a repurposed Wharfedale SFB baffle that I don't want to modify, so it has to be a 12".

mondogenerator 16th December 2010 04:49 AM

Quote:

Originally Posted by Racket Scientist (Post 2400240)
The more I look at the GRS I realize I shouldn't have even bothered including it for consideration. Any other contenders for a 12" helper woofer below about $100 I should consider? I'm using a repurposed Wharfedale SFB baffle that I don't want to modify, so it has to be a 12".

maybe Fane have a suitable driver?

GM 16th December 2010 06:22 AM

Historically, one acoustically fit the driver to the baffle, i.e. matched the driver's mass corner (2*Fs/Qts) to the baffle's effective width with a Fs ~a half octave below the baffle cut-off, though nowadays EQ is used to shape its response, so whatever driver is within budget that has a low enough Fs for the baffle size + any boundary loading and high enough Xmax/power handling and/or high Qt (up to ~1.5 depending on the desired mass corner) to meet the SPL desired.

Easiest to just try different drivers in Basta!, MJK's MathCad OB worksheet or similar.

GM

mashaffer 17th December 2010 12:22 AM

Alpha.

kristleifur 17th December 2010 09:57 AM

Quote:

Originally Posted by GM (Post 2400367)
Historically, one acoustically fit the driver to the baffle, i.e. matched the driver's mass corner (2*Fs/Qts) to the baffle's effective width with a Fs ~a half octave below the baffle cut-off, though nowadays EQ is used to shape its response, so whatever driver is within budget that has a low enough Fs for the baffle size + any boundary loading and high enough Xmax/power handling and/or high Qt (up to ~1.5 depending on the desired mass corner) to meet the SPL desired.

Easiest to just try different drivers in Basta!, MJK's MathCad OB worksheet or similar.

GM

Thank you! I must say, that is a well crafted explanation. A taut construction of intuition and engineering terms complementing each other; left-right-left-right-knockout.

Nelson Pass 17th December 2010 04:56 PM

The Beta is really the better driver.

:cool:

c2cthomas 17th December 2010 06:09 PM

Quote:

Originally Posted by kristleifur (Post 2401626)
Thank you! I must say, that is a well crafted explanation. A taut construction of intuition and engineering terms complementing each other; left-right-left-right-knockout.

Heh - SWMBO is watching Sherlock Holmes at the moment - the fight scene just played out. :D

pboser 17th December 2010 07:44 PM

Some people really like the Tone Tubby 12". Here's some info, but it looks like it's used here less as a helper woofer than a fullrange candidate. The 12" Alnico Tone Tubby

Andrew Eckhardt 17th December 2010 08:02 PM

I accidentally recently ordered some Alpha 12's instead of the Beta12A2s. Because it will cost me 15 bucks to send back a pair of the Alphas I tried really hard to fit them into any project I could conceivable start.

They're in the box and going back. They're really about half a speaker, and for another 10 bucks you can get a real one. I'd suggest to figure out an electronic/electrical way to control the Q for the OB application and use a Beta.

I don't know what your amp situation is like but the Alpha 12A is probably only quite reasonable down to 50Hz OB if you have less than 15 watts to work with or something.


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