Dipole/Bipole Designs?

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Does anyone know of any good reference material for designing dipole and bipole speakers? Specifically dual driver speakers as used in surround systems rather than the open baffle dipole style.

I have looked for good solid info and am struggling to find anything sensible on what the design parameters need to be.

For instance, can I use a single tweeter facing into the room with a pair of side firing woofers, one facing the front of the room one the back? (this assumes a side wall mounted surround speaker).

What if I make the cabinet trapezoidal in shape, do the rear and front firing woofers have to be at 180 degrees to each other or is, say, 120 degree enough?

I know just enough on this subject to be dangerous so need an education :)

Thanks,

Marcus
 
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I have no experience with surrounds as described but some with dipoles (ESLs) and of late bipoles -- i'm on a bipole kick right now.

There is some bipole info on this bipolar ml-tqwt concept and some on my BD-Pipes page.

If you are going to a dipole surround each midbass should be in its own subenclosure or you will get NO bass, and the 120 degrees seems more sensible than 180 degrees.

dave
 
Hmmm...

I wonder if one option to get around the bass cancellation issue is to use only a single woofer firing into the room and then using a pair of tweeters in the dippole arrangement?

I guess for this to work you would need to cross the tweeters over very low or the localisation effects of the woofer would be the dominant effect.

As I said, it is surprisingly difficult to find published info on this subject!

Marcus
 
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Marcus said:
As I said, it is surprisingly difficult to find published info on this subject!

One of the reasons may be that the dipole was intended to overcome issues with Dolby ProLogic, now that Dolby Digital reins the dipole is no longer considered best.

I'd do a 120 degree "bipole". Actually i have a set of omnis downstairs in need of finishing.

dave
 
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