Why do subs with a d2 coil have more BL?

[Fi 4 life 0]

Look at title. As an example, a 15" Fi SSD both D1 and D2 have the same specs except for a 40% higher BL on the D2, can someone please explain what is happening that makes this configuration have that much more motor force?

[NDMstang65 403]

Ohms law, coil is wired in series..more turns in the gap with a D2 coil than a D1 coil.

 

A dual 4ohm coil will end up with about another 50% BL across the D2

[Fi 4 life 0]

Thank you,tried telling my buddy that but he wouldn't believe me

[Lee Carter 150]

I have noticed that too- so does that translate into a harder hitting sub?  enough to be audible?  I would think that it that were true- no one would want D1's in favor of D4's.

[Duran 387]

No. It's not audible or more hard hitting.

[cloud77 28]

great post

[Lee Carter 150]

Thanks Duran.

[95Honda 484]

I think one thing that people forget in car audio is that the lower the impedance, the worse everything performs. 

[Impious 1,467]

Keep in mind that while BL increases, Re also doubles which means less current through the motor.

 

Using the standard BL²/Re to express the motor force factor, the D1 SSD15 would have a force factor of ~123 while the D2 SSD15 would have a force factor of ~125.

 

As you can see, they are virtually identical.