[ThePCWizard]

So I was thinking about the challenges posed by using multiple drivers in a pair of headphones. I came accrossed the thought of using a dynamic driver with a hollow center rather than a typical dynamic driver. It would look more like a ring rather than a disk.
 
I'd assume that using two or three of these drivers within eachother would provide a more uniform sounding experience rather than having two or three typical drivers next to eachother. I'd also imagine we might have some interesting mounting possibilities with such speakers.
 
What do you guys think of this idea? What benefits and what problems might be posed by using such a driver?
 
Also, if these already exist, what are they called? I'd be interested in doing some research on them.

 

[Music818]

Do you mean a driver somewhat like the HD800?

 

[ThePCWizard]

  Do you mean a driver somewhat like the HD800?

No, that's not at all what I'm talking about here.
 
The drivers would be rings, a 40mm driver might fit in the empty space of a 60mm driver that has a 40mm inner diameter.
 
It would work something like this, except with drivers and not two metals in a coin.

 
20mm tweeter, 40 mm woofer, and then even a 60 or 70mm "subwoofer" if you want to get crazy.