dumb question about dual opposed

Good question.

I'm pretty sure they need to be aligned with one another. Though I'm only 99% sure about that.

Aren't most dual opposed separate chambers anyways and sealed?

once moved off center, they will create a twisting torque that will lose energy into moving the cab vs. creating sound.

solving for how much loss is extremely complex.

hmmmmm

what about this piece of space debris -- how does it work?



I think I'd buy a plane ticket to hear it in action...

http://www.edesignaudio.com/product_...roducts_id=607

No most are shared chambers, which equalizes pressure and some harmonics. They don't have to be perfectly even, but you shouldn't have them to far off a common center.

space debris is a simple cardioid iirc.

That makes it sound all or nothing.

Benefits decrease smoothly from the drivers being directly opposite.

You could build a push pull subwoofer like M&K

I never understood the selling points of the M&K designs. You cancel some harmonic distortions, but save no space like an isobarik design. If you want a certain cabinet depth I guess it works.

It's simply a dual driver design that gets some of the advantages of dual opposed, but the driver arrangement allows you to place it in a corner or soffit if desired. The close proximity of the drivers will also allow even order HD cancellation to a higher frequency than wider spaced driver arrangements.It's not intended to save volume like an isobaric can, but it also doesn't waste the 2nd driver's Vd and half the power like an isobaric does.

http://audioroundtable.com/PiSpeaker...ges/19880.html

More info on push pull for those that want it

It's a good article, but the 2H cancellation he gets is by operating them into a common chamber and keeping them very tightly spaced, the latter of which I mentioned above. EV did a direct radiator push pull PA sub some years ago, with the drivers going into a common manifold, very similar to what WP did with the Pi12, but without the horn attached to the front. M&K could have done the same, but it does make it difficult to build in some form factors.

The attachments make it easier to visualise in the drawing (plenum can be slanted or square to baffle) and the second is a finished build by Les Hudson who posted about it at AA and is based upon the work of EV and poster 'djk'. It's a 2x12" push pull slot loaded ported.