Dual cone voice coils

[bsco]

I never ran into this yet until now....So....I want to test the electronics to see if it is ok..I do know that the speaker is open....it has dual voice coils....Is it ok to hook up a dummy load to the amp to one speaker terminal pair at a time...I have an 8 ohm load....I just want to test the electronics to see if they are ok....if the electronics is bad and the speaker is also blown, then it might not be economically feasable......
Cheers

[The Dude]

I'm assuming solid state amp? You don't need a load to test. Check for DC first. That might be what roached the speaker.

[bsco]

I'm assuming solid state amp? You don't need a load to test. Check for DC first. That might be what roached the speaker.

Thanks for the quick reply...Yes..it is a solid state....powered speaker....JBL I believe.....Of course the usual...Somebody fed it booze......

[The Dude]

Maybe it's just drunk? Did you try pouring some coffee in it?

[bsco]

Maybe it's just drunk? Did you try pouring some coffee in it?

Hahahaaa...If i thought it would help, I would.....

[Enzo]

JBL makes a dual voice coil speaker? Why on earth?

[J M Fahey]

JBL makes a dual voice coil speaker? Why on earth?

Because they can

No, seriously, , it's a new idea, they even patented it.

With a regular speaker pointing up, you have a ring magnet in the middle, a top plate on top with a hole, a solid bottom plate, and a pole piece magnetically joining them, which is firmly attached to the bottom one and is smaller in diameter than the top plate hole, where the voice coil lives.

I guess somebody thought "what if?" and added a gap at the bottom plate too, so he could have a second voice coil helping push the cone.

In theory a killer idea, doubling speaker "engine" for free; in practice gap length is doubled, so you need roughly double the magnet to push through.

A deal killer with Ceramics, became practical with Neo and other modern magnets.

The actual VC:


Chinese copycat:


the car audio approved nightmare:


the patent:

[bsco]

Thanks for the pics JM....