Boxy colouration from IB manifolds?

[chrisbee]

Is there any evidence for boxy colouration from conventional manifolds?

Flaring the sides (like truncated pyramids) might raise isses of short horn loading for out of band frequencies.

It also introduces some vibration cancellation issues depending on slope angle.

Any thoughts on how manifolds might be improved or at least optimised in future IBs?

Or is this yet another non-issue like flaring the edges of the manifold opening?

If it aint broke... don't fix it? ;D

[ThomasW]

I've never been in a situation where I could A/B a mainfold vs a line array. My experience with dipole subs makes me believe that line arrays inherently offer the best SQ.

It's possible that a short pyramidal shaped box with a large opening would be a good mainfold. This because there would be less 'box' to interact with. Even better might be a hemisphere, though there's little evidence that in a ported box, a round port moves air any better than a square/slot one.

Fortunately our standard manifold ends up sounding so much better than any standard 'box' sub, there's little motivation for a big study trying to wring out the last 10% of improvement.

[chrisbee]

Interesting. Thanks, Thomas.

I'm still trying to decide how best to optimise a possible change from my array to a manifold centred over my main speakers.

Any particular reason for suggesting a hemispherical manifold? Just a whim? Or did you have the feeling it might offer an extra something?

A high level of stiffness to radial loads, no panel resonances & absence of parallel surfaces. It certainly looks like a useful contender. Downside is greater overall dimension than typical joist spacings if the manifold is hidden.

I wonder what optimum diameter I should be looking at for a 4 x 15"?