[rick57]

For active OB dual 12 inch woofers (120 ? 20 Hz, EQed) where a more modest size helps with WAF, what OB 'enclosure' shape is the best option?

Martin King did an excellent study from the point of view of bandwidth and efficiency.

For modest size, preferably without too severe resonances, is Linkwitz' design still the best? http://www.linkwitzlab.com/woofer.htm

Those particular dimensions produce a resonance at 270 Hz 
http://www.linkwitzlab.com/sys_test.htm - half way down under Dipole woofer.
As SL says, this can be attenuated with a notch filter . .

Or unless minimal size is really critical, just do a W frame ie, a double M?

I wont have time to experiment - is there a "proven" form other then U, H, M/W and Linkwitz's?

Thank you

[taloyd]

Linkwitz W-frame has the advantage of even-order harmonic distortion cancellation as well as reducing box vibration. Both make a sizable contribution to sound quality. The box also ends up being fairly compact. The only issue is the resonance, which can be dealt with using a low/steep crossover and if necessary a notch filter.

Unless your mains are VERY small though, I would try to crossover a bit lower...

cheers,
-Tal

[Telstar]

Why dont you tri a Ripole? There's nothing more compact

http://www.lautsprechershop.de/hifi/index_en.htm?/hifi/ripol_en.htm

[scorpion]

I am a little curious how an H-baffle with say the 15" Eminence Alpha measuring 17.5 x 17.5 x 16 " (BHD) would be considered much bigger than a Phoenix Baffle (which I would call W-baffle) measuring 19 x 14 x 19 " (BHD). You have read MJK's study, you can also read Godzilla's view about his Alpha H-baffle here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=131590&perpage=25&pagenumber=6 .

/Erling