List of Underhung, 12", Small Box Woofers.

[bose301s 5,000+ posts]

XXX, Brahma, SDX, Gti, Koda (newer ones), Avalanche, new Mag, etc etc etc.

I think he meant one with all 3 of the technologies in one.

As for Differential Drive, I was under the impression that it was not a BL optimization technique but rather an inductance lowering technique that also allowed for electric "braking" of the driver.

Also you left out LMT/LMS.

 

[dftnz7 10+ year member]

BL optimized as in xbl^2/splitgap/differential drive. Not underhung.

Sorry, I often mistakenly think of the term "underhung" as a broad way to describe anything that is not traditional LGLC.

 

[audioholic 5,000+ posts]

I think he meant one with all 3 of the technologies in one.
As for Differential Drive, I was under the impression that it was not a BL optimization technique but rather an inductance lowering technique that also allowed for electric "braking" of the driver.

Also you left out LMT/LMS.

You are correct about differential drive, as to the implied use of the technology. I was under the understanding that it lead to a flat BL curve as well. But now that I think about it, Ive never seen a BL curve on a diff drive motor.
I left out alot of BL optimized drivers, that's why I said etc. I also didn't mention the W7, with its proprietary BL optimization techniques. Was just a brief list meant to illustrate my point.

 

[skateboardkid 10+ year member]

JBL MKII has the differential drive I believe..

It brakes itself before it has two much excursion - it might be the split gap technology - actaully they say it has the differential drive with split gap tecnology - so there is another one.

YOu say the mag doesnt have enough excursion, however from the reviews I have read it does not lack any low end extension or output with the amount of excursion it has now.

 

[Electrodynamic 10+ year member]

With 600 watts and 1.1 ft^3 sealed you don't need a lot of throw. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif And as the others have stated, the new Mag has a shorting ring, extremely low inductance, BL optimization (XBL^2), is only 5.5" deep, was designed to work in exactly 1 ft^3 sealed, and only weighs a tad over 20 lbs.

 

[Kyle_Keating 10+ year member]

Underhung is far from a new technology. If you want new tech in a motor, you want one that is BL optimized.

actually under hung is BL optimized, its the oldest method of getting linear BL. Underhung motors are very linear and they are pretty easy to design, but the issue is its very hard to get high xmax out of them, and when you go beyond xmax, the bl drops like a rock and coils will accelerate out of gaps causing all kinds of non-linear distortion because the back emf drops so much when the short coils starts to leave.

 

[Kyle_Keating 10+ year member]

I think he meant one with all 3 of the technologies in one.
As for Differential Drive, I was under the impression that it was not a BL optimization technique but rather an inductance lowering technique that also allowed for electric "braking" of the driver.

Also you left out LMT/LMS.

correct, but i would also add Diff Drive is a "sensitivity" optimized technique at the expensive of linearity. Short overhung coils in two gaps.. very sensitivite, not linear at all and in fact, when movement beings huge, the BL reverses so its very much anti-linear at that point.

 

[squeak9798 5,000+ posts]

But now that I think about it, Ive never seen a BL curve on a diff drive motor.

http://www.diymobileaudio.com/forum/showthread.php?t=11864&highlight=W12GTi

And now you have //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[dftnz7 10+ year member]

^ Regardless of semantics on motor topology of modern subwoofer designs; random, silly excerpts from Tool should, without a doubt, replace fairy tales in the nurturing of young children.

 

[audioholic 5,000+ posts]

http://www.diymobileaudio.com/forum/showthread.php?t=11864&highlight=W12GTi
And now you have //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Thanks squeak. Interesting info in this thread.