How low in bass do dipole surround speakers go?

[goldyrathore]

Hi,

Many surround speakers use dipoles where the listener is placed in the null
area. With the typical 4"-6" size of the bass drivers used in them, there
cannot be enough bass even on-axis.

Do they really produce bass till 80Hz (-3db)?
What is the real -3db point?

Thanks,
Goldy

[Bigun]

The idea is to generate a sound field around you ('surround') and a direct radiating speaker just to the left and right of the listening position is sometimes too directional. The dipole speaker will generate a sound pattern that avoids this and the output will bounce of other surfaces to increase the 'surround' effect.

[planet10]

The dipole as a surround is an artifact of the original (poor) dolby surround scheme. There is absolutely no reason to use them at all these days.

Toole has a good analysis of this. In short -- just forget that dipole surrounds ever existed.

dave

[chris661]

In my limited experience, (ie, dipole surrounds vs bipole vs monopole), I found the dipole ones had a more immersive surround, with decent positioning between the speakers - tested with the Dark Knight, one of the iMAX scenes where a machine gun shoots a metal panel and it sounds like it pans behind you. Used a pair of 2.5" Sony widebands.

I suppose, in the end, a lot will depend on room placement. These were up against the same wall as the sofa, yet still managed to steer the effects behind you, regardless of listening position. To me, that's an ideal surround speaker. In free(er) space, I don't know if they'd do so well.

Dipole surrounds usually have one bass driver and two tweeters (or two mid-high drivers). The lower frequencies would be monopole, the higher ones would be dipole. In this case, bass to 80Hz can be expected.

Chris