Bipolar speakers

[grana]

Hi, this is more a theoretic question. I am considering buying Focal Aria SR 900 for a HT setup, but I can't quite get why I should prefer these bipolar speakers over regular ones.
If I think how the sound diffuses and reflects in a room, I think the effect of a bipolar speaker is that the sound becomes "messy" (sorry for the lack of lexicon here). The same sound being output from the two poles of a single speaker will reach my ear from two different directions, and at two different times.

What am I missing?

 

[Philbo King]

It's the Bose Effect - bounce the sound around for a while... Though I'm not sure why they name it after a sexually ambiguous white bear.

 

[Berwhale]

I feel like bipoles are a bit of a leftover from the surround sound days (i'm not dissing bipoles, I have a pair of Mission M-5DS high up on the sidewalls in my lounge )...

From: https://www.harman.com/documents/LoudspeakersandRoomsPt1_0.pdf

Parts 2 & 3 here:

https://www.harman.com/documents/LoudspeakersandRoomsPt2_0.pdf

https://www.harman.com/documents/LoudspeakersandRoomsPt3_0.pdf

 

[Vincent Kars]

Though I'm not sure why they name it after a sexually ambiguous white bear.

No, it is named after a disorder.

 

[grana]

so the TLDR is: don’t. Stick maybe with https://www.focal.com/en/home-audio/high-fidelity-speakers/chora/chora-surround? I’m surprised there’s no higher end surround speaker for Aria

 

[Digby]

No, it is named after a disorder.

I thought it was named after someone who circumnavigates the globe, top to bottom.

 

[Duke]

I would call the Focal Aria SR900 a "splayed array", the intention presumably being to get relatively wide and uniform angular coverage in the front hemisphere.

The Mirage M1, @Floyd Toole's speaker of choice during his years at the Canadian National Research Council, was imo a proper bipolar loudspeaker.

 

[ryanosaur]

FWIW, I have been under the understanding that if you are placing Speakers very near-field (like Surrounds or Rears) Bi-Poles can help diffuse the sound so they aren't "beaming" straight at your ears or need to be aimed away so as to be too far off axis to be worthwhile. However, if you have a situation that allows for more optimal placement, Bi-Poles can muddy up the sound field so spatial surround queues are not as effective.

I've never used them, but this was the best and clearest use case recommendation I had ever read from an experienced installer. *shrugs So, grain of salt(?), perhaps.

 

[Duke]

FWIW, I have been under the understanding that if you are placing Speakers very near-field (like Surrounds or Rears) Bi-Poles can help diffuse the sound so they aren't "beaming" straight at your ears or need to be aimed away so as to be too far off axis to be worthwhile. However, if you have a situation that allows for more optimal placement, Bi-Poles can muddy up the sound field so spatial surround question are not as effective.

I've never used them, but this was the best and clearest use case recommendation I had ever read from an experienced installer. *shrugs So, grain of salt(?), perhaps.

Yes!

Because the pattern is double-lobed at high frequencies, "on axis" (in the center of the coverage pattern) there is no "hot spot" to draw attention to the fact that a speaker is close by. The inverse-square law ramps up the SPL rather quickly at close range which can make the nearest side surround speaker too loud and therefore localizable by listeners (viewers) seated close to one of them, especially if they are on the tweeter's axis. But if our off-to-the-side listener is seated in the middle of that double-lobe pattern, this effect is usefully mitigated while still covering the rest of the room well.

To put it another way, the relative sound pressure levels of the front speakers and surround speakers should be within a particular range in the listening area, but when one of the listeners is much closer to one of the side surround speakers, that speaker can end up being TOO loud. The splayed array configuration (commonly is called "bipolar" in home theater parlance) for the side surround speakers helps to address this potential issue.

 

[Chrispy]

so the TLDR is: don’t. Stick maybe with https://www.focal.com/en/home-audio/high-fidelity-speakers/chora/chora-surround? I’m surprised there’s no higher end surround speaker for Aria

The same speakers as mains would be ideal surround speakers....using an on-wall bookshelf sized speaker is more about convenience....

 

[DVDdoug]

If I think how the sound diffuses and reflects in a room, I think the effect of a bipolar speaker is that the sound becomes "messy" (sorry for the lack of lexicon here). The same sound being output from the two poles of a single speaker will reach my ear from two different directions, and at two different times.

I basically agree... But I've just started reading Floyd Tool's book and I assume he discusses this (or this kind of thing) and I don't consider myself an expert, yet...

My non-expert opinion is -
It's a personal preference thing and since the vast majority of speakers on the market are "traditional" more-directional speakers, I assume that's what most people want. Studio monitors are also traditional forward-projecting designs.

The sound of a bipolar or omnidirectional speaker should be more-affected by the particular room acoustics than a regular speaker. You might like the reflected sound more in one room and less in another, and a traditional speaker should be more consistent in different acoustic environments. (But acoustics ALWAYS make a difference and sometimes a BIG difference.)

Though I'm not sure why they name it after a sexually ambiguous white bear.

More seriously, I'm pretty sure it's from the famous Bose 901 direct-reflecting speaker which had 9 small full-range drivers. One faced forward and 8 were on the back, angled toward the side & rear walls.