2Pi to 4Pi transition and box shape

[Moondog55]

I've seen one or two comments on this subject but nothing substantive.
Before I go ahead with the next set of speakers I'm asking for opinions.
If building a bass box and using front and rear firing drivers there is a null at each side where wave-fronts meet, what happens when drivers are mounted in other ways??
If using two drivers facing forwards and at 45degrees to each other is this better or worse?? and what about a triangular box with a driver on each vertical face??

[LineArray]

Hi Moondog,


when operated as subwoofer the enclosure depth is
normally small compared to wavelength.

From my gut feeling depth of lambda/8 should not cause
serious change in radiation pattern.

This would be a depth of 40cm at 100Hz ...

If the polar diagramm gets a little egg shaped, would that
be a problem ? One could use that behaviour to compensate
room problems in upper bass by rotating the sub as you like ...

With one front and one backfiring driver you get impulse
compensation, the cabinet will stay very quiet if built stiff
enough ...

So maybe think about leaving the sub as it is.

Cheers

[sreten]

Originally posted by Moondog55

.......... If building a bass box and using front and rear firing
drivers there is a null at each side where wave-fronts meet, ....

Hi, for in-phase drivers there is no null, for out of phase there is no bass, /sreten.

[badman]

if they're subs, and not an attempt at dipole subwoofering, then you should be fine with mounting them any way you please- opposite each other allows you to do force cancellation though.

[Moondog55]

Actually I was imagining Tri-pole if such a beast exists.
Still thought experiments, but the woofer side of things will be Di-poles, I was thinking of subwoofers here and wondering if the mythical perfect box exists.
Sreten, Hi; the drivers will be in phase

[sreten]

Hi,

FWIW for a subwoofer monopole, bipole, tripole, quadpole .... are all the same.
Except the lack of force cancellling in a monopole.

/sreten.

[Moondog55]

Thanx Sreten, that makes it easy