Yeah, but the point was maximized cone area. I really just wanted to know why they weren't around when there are squares.

The Solo X 18 D4 looks really nice and models to .707 in 5 cubes @ 37.88 HZ. How does it perform in a sealed box?

 

I would guess because they are so big not many people would purchase something that large.

 

space is at a premium when your dealing with subs to begin with.

 

Many people own 18's and space is not an issue with subs or a sealed box for that matter.

 

space is only an issue if you're lazy

As to the issue of rectangular subs, they are not popular to design because the cone would be hard to make stiff enough while remaining "light". Also the coil to cone ratio is something to take into consideration. With a "small" coil you can only generate so much motor force (ignoring the magnet structure and staying with traditional designs).

If you used multiple coils or "larger" coils then the issue is reduced, but you also gain weight and lose spider width which restricts excursion.

Its doable for sure and you could make something that would keep up with whats out today if you wanted.