Motor structure madness!

[KennyG]

What happens to the magnets when two drivers are mounted motor to motor, in a Isobarik design?
The object is to make the pneumatic coupling cabinet as small as possible, right?
So if you want the most out of this design, and don't want a driver hangin' out in free space and lookin' ugly, then one driver must go in the cabinet and face the opposite way. This puts the drivers end to end. Will the resulting magnetic field interaction weaken the magnets over time? Will it weaken the fields in the here and now and cause a "less powerful motor"?
Looking at the way the magnetic lines of flux flow...could it actually strengthen both fields???? KennyG

[ThomasW]

Kenny

If you want front to back then mount the drivers as close together as possible. Leave enough space so that at maximium forward excursion the dust cap of the rear cone won't hit the front magnet, then add some extra for good measure. I'd suggest .5" additional gap.

If you want back to back then again, use .5" between the magnets

Now please go fixate on something truly serious, like the odds of getting hit by lightening. :B




theAudioWorx
Klone-Audio

[KennyG]

I would think the possible inductance changes in the driver's motor, caused by interfering magnetic fields might be a worry for designers.

[ThomasW]

Effects of things like "bucking magnets" do make small changes is the T/S parameters. The situation would be similar with magnet to magnet mounting.

Isobaric designs have been around for several decades. But no where in any literature dealing with isobaric design is this topic brought up as a significant issue.

I was purposefully being flip with my original answer. Please realize that ANY significant problems that could occur with sub design and construction, would be made known at the outset of a discussion. This is especially true with people like Dan Wiggins, Greg Monfort, JonMarsh, and myself. It's contraindicated for us to aim anyone in a specific direction, and not provide ALL pertinant caveats.

Perhaps you missed the isobaric thread where Greg and I discussed isobaric mountings arrangements. He and I agree that front to back, or back to back are the preferred configs. Also both of us feel that there is minimal benefit to trying to cancel the harmonics of the modern woofer designs, since the distortion levels are so low. So if you are concerned about magnet to magnet mounting problems, then mount the drivers front to back.

If you want to research acoustical design and engineering start here

http://www.aes.org/journal/search.html

theAudioWorx
Klone-Audio