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el`Ol
12-11-2007, 06:56 AM
Hello all!

Just read the (exspired) Manger patent and saw one of the drive alternatives uses some kind of differential drive. I donīt know whether the Mangers actually use it, I just know the MSW has two coils.

http://www.freepatentsonline.com/4029171.html
Allanvh5150
12-11-2007, 11:37 AM
I have had Alpine DDW F30A subs in my car for 12 or so years, so yes they have been around for a while.
Thom
12-11-2007, 01:18 PM
Hello all!

Just read the (exspired) Manger patent and saw one of the drive alternatives uses some kind of differential drive. I donīt know whether the Mangers actually use it, I just know the MSW has two coils.

http://www.freepatentsonline.com/4029171.html

The differential drive has a gap for each VC. Other dual VC designs do not. I couldn't see that in the patent but may have missed it.
el`Ol
12-12-2007, 12:11 AM
The differential drive has a gap for each VC. Other dual VC designs do not. I couldn't see that in the patent but may have missed it.

In the Manger patent the two coils are on one voice coil former with the field of the two gaps in opposite directions.