Keep an eye out for the driver excursion / Xmax of the main unit. Unfortunately, there aren't really any direct equivalents to the old Goodmans wideband units like the 401, and although the extra cone area helps a bit, it's not ultimately going to prevent any problems like those mentioned above. BTW -I assume you realise the Alpair10 is a 5 1/2in driver?
As for 30Hz, you're asking a lot of 12in bass units on a relatively compact U-frame. It should be feasible (just) but your dynamic headroom will be vanishing. Personally, I doubt I'd try taking 12in drivers below 40Hz, run OB. Well, not less than 4 of them anyway.
As for 30Hz, you're asking a lot of 12in bass units on a relatively compact U-frame. It should be feasible (just) but your dynamic headroom will be vanishing. Personally, I doubt I'd try taking 12in drivers below 40Hz, run OB. Well, not less than 4 of them anyway.
Scottmoose said:
No, I overlooked that. Thanks.
I'm trying to understand if I need 15" drivers for that or that i can manage someway with the smaller ones. In waf points 5cm each speaker are worth a lot
A few months ago, John of AE Speakers ran a simulation for me with (dont remember if one or two) OB15 drivers in a 40cm baffle and the 30hz objective was possible to achieve. There's still the thread on audiocircle.
Also, 2x 15" Augies can go as low as 25hz, measured by some of the users.
3x 12" drivers in a baffle that looks like the CS2 would be accepted with flying colors. One 15" and + one 10" (for instance) + eventually a tweeter, much less.
Something to remember is that OB tends to have a point of diminishing returns in the LF regions; even Linkwitz went monopole for use below 40Hz.
Anyway, you'd stand a better chance (and get better sound) with 15in units than 12in if you really must try to get a theoretical flat to 30Hz out of them (in practice, it's questionable if they'll actually do it due to room issues).
Anyway, you'd stand a better chance (and get better sound) with 15in units than 12in if you really must try to get a theoretical flat to 30Hz out of them (in practice, it's questionable if they'll actually do it due to room issues).
Scottmoose said:
I think that the only 12" drivers that can reach 30hz are the AE OB12, with U frame (cant use H for WAF), bass boost and EQ.
89dB, Fs=28 hz, Qt=0,47 and Xmax=18 mm.
To reach about 95dB peak should be doable? Tempting bet...
Oh anyway i can live with not perfectly flat, -3/db at 30hz wouldnt kill me as long as i can hear the piano lowest notes.
I'm reading the last project of MJK with the Goldwood 18" woofer. Similar goal to mine but different approach (he wanted passive/low eff).
I have room modes at higher freqs, the first start at around 45hz and its a rollercoaster up to 110hz. That's why I want all this range to be taken care by an extremely accurate computer EQ.
But what scotts saying is that there's little room left at 30hz for dynamics is important. Assuming your not going to play test tones.
I too don't feel I can't use 15" drivers. I've pretty much decided on two 12" with a boxed sub. I also believe that there's a tradeoff with detail and accuracy with a inexpensive 15" pro driver. I believe Dayton makes a few 15" drivers they call hifi. The advantage may be more emphasis on accuracy and less on power handling. A driver being capable of handling 700w is not necessarily a good thing.
I too don't feel I can't use 15" drivers. I've pretty much decided on two 12" with a boxed sub. I also believe that there's a tradeoff with detail and accuracy with a inexpensive 15" pro driver. I believe Dayton makes a few 15" drivers they call hifi. The advantage may be more emphasis on accuracy and less on power handling. A driver being capable of handling 700w is not necessarily a good thing.
dzzmiller said:But what scotts saying is that there's little room left at 30hz for dynamics is important. Assuming your not going to play test tones.
I too don't feel I can't use 15" drivers. I've pretty much decided on two 12" with a boxed sub. I also believe that there's a tradeoff with detail and accuracy with a inexpensive 15" pro driver. I believe Dayton makes a few 15" drivers they call hifi. The advantage may be more emphasis on accuracy and less on power handling. A driver being capable of handling 700w is not necessarily a good thing.
From 30 to 200 (maybe less) hz, the driver sound quality isnt that important. The better drivers (i.e. AE Dipole15) go higher smooth and makes sense for who cut at 3-400hz.
I never heard people that uses boxed subs to complain about it (while i do for other reasons, i hate boxed bass that resonates everywhere).
The important specs are the ones that Scott mentioned, Qt, Xmax, sensitivity and Fs, and of course the response graph.
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