The shape of the enclosure *has* effect
on the sound.
Every enlosure has resonance
modes. If one dimension is made longer
(so the two others are getting shorter),
the volume is preserved, but the first resonance
is getting lower. Usually it is suggested
to have sides like 0.8:1:1.25, so the resonance
modes are spread and not on the same spot.
In a subwoofer perhaps 1:1:1 is better, if
this prevents the lowest resonance to be inside
the used bandwidth (the 1.25 side would
otherwise lower the resonance a bit).
The first choice is getting the resonances
higher, the second choice is absorbing material.
Note that velocity is 0 at the walls.
In order to be effective, the absorber must be
where velocity has maxima. Often the only way
is to fill the complete volume.
Enclosures have modes, regardless of shape.
Cylinders, pyramids, spheres, irregular,
no matter what you do, resonance modes will
exist. The pattern of modes will be different
for each example, however.
If you follow the link you can select
"room-resonances".
A cabinet is a small room. It is made for
a cuboit room, but you can see the main idea.
A cylinder has other modes, but not totally
different.
m.c.
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