Question Bi-pole, Di-pole or Direct in an Atmos Setup

sjackson

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So here's a question and I'm not even sure if it matters.

I'm mid-way through a system upgrade and getting an Atmos amp but for now will be running in a 7.1 setup. For the fronts I have 3 x Apex A40 and the rears a pair of Apex A10's. For the side surrounds I have a brand new set of Monitor Audio RXFX.

While the RXFX can be run in bi-pole or di-pole for a 7.1, would I be better off with direct firing speakers in an Atmos setup?

The burning question is do i hold onto my RXFX for now or sell them while they have a premium and replace with either a pair of A40's or a pair of A10's.
 
Purists will probably say direct radiating speakers. However it all depends on your room layout, even with ceiling speakers I don't believe would like direct radiating speakers for side/surrounds.

Since your speakers are selectable to bipole I'd probably leave them on that. Also, try using your front speakers as rears as see what you think. Try playing back a movie with bipole rears playing with your RXFX, with the fronts off. Then move your fronts to the rears then try it again. Basically comparing what bipole, and direct speakers do as surrounds. Granted you don't have Atmos yet but at least get an idea which type you prefer.
 
The purpose of ATMOS is to locate a sound in precise 3-demensional space, I don't see a diffused speaker like a Di/Bi-pole being conducive to precisely locating a sound.

That doesn't mean it wouldn't work, it just means, while you will get the effect, it will be less precise.

We can already, more or less, locate a sound in 2-dimensional space, it not uncommon to hear Lead Guitar on the left, Rhythm Guitar on the right, and vocals and bass in the center of the sound stage .. or similar. Or to hear a car chase zooming from left to right, or perhaps even front to back.

However, ATMOS offers to place sound precisely in vertical space. When planes fly, the literally fly overhead moving above you through the room. It would seem to get that precision, you would need a more direct speaker.

Now, with diffused Bi/Di-pole speakers, the planes will still be overhead, they will still move from back to front, but I WOULD GUESS, there location would be less precise.

However, I admit that is nothing more than my opinion. ATMOS is very new, and I think very few have enough experience to say what will and what will not happen.

Steve/bluewizard
 
The purpose of ATMOS is to locate a sound in precise 3-demensional space, I don't see a diffused speaker like a Di/Bi-pole being conducive to precisely locating a sound.

That doesn't mean it wouldn't work, it just means, while you will get the effect, it will be less precise.

We can already, more or less, locate a sound in 2-dimensional space, it not uncommon to hear Lead Guitar on the left, Rhythm Guitar on the right, and vocals and bass in the center of the sound stage .. or similar. Or to hear a car chase zooming from left to right, or perhaps even front to back.

However, ATMOS offers to place sound precisely in vertical space. When planes fly, the literally fly overhead moving above you through the room. It would seem to get that precision, you would need a more direct speaker.

Now, with diffused Bi/Di-pole speakers, the planes will still be overhead, they will still move from back to front, but I WOULD GUESS, there location would be less precise.

However, I admit that is nothing more than my opinion. ATMOS is very new, and I think very few have enough experience to say what will and what will not happen.

Steve/bluewizard
Bipole and tripole speakers work perfectly well in an Atmos system. Dipole possibly not so well.

Tripoles have the edge as they image extremely well. Several high end firms around the world are using bipole or tripole speakers in Atmos systems. These are as ceiling speakers and surrounds.
 
For side surrounds I don't want precise effects because I'm close to the side & rear walls, so I need the diffusion certain speakers offer. Monopoles are just too obvious.

This sort of question would have to be answered by own testing, in your own room, I wouldn't take whatever Dolby state as Gospel as no room is the same.

I would probably agree dipoles are now not the ideal type, however it's not the end of the world if you already have a pair just open the out of phase side and reverse them
 
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Just as a reference, here is a graphic that illustrates the difference between Di-Pole and Bi-Pole speakers. It has to do with the phase of the front and rear firing drivers that make up the speakers.

Bi-Di-Pole-1.jpg



Though as well as Left and Right components (as you face the speaker) some also have a forward facing driver.

But the key is diffused sound.

I'm not sure how precisely ATMOS intends to place a given sound component in 3-dimensional space, and while I admit pure speculation, it would seem a more diffused speakers would be less able to to that. Though I admitted it would still likely work, just less precisely as I imagine the degree of needed precision.

I will also say that, every system is a compromise. We have to accommodate our physical spaces and our budgets, not to mentions the ever looming Wife Approval Factor. It is entirely possible that in your space, with your needs, and your budget, Di/Bi-pole speakers are the best solution.

ATMOS is too new to really know and understand the details and the effects, so clearly everything I say is speculation.

Steve/bluewizard
 
You have to remember how di-pole and bi-pole speakers create their dispersion pattern though Steve. They are very different and shouldn't be grouped together.

Di-poles, by design, create a null in front of the speaker with the aim of the listener being within that null. The ratio of reflected versus direct sounds that the listener hears is therefore biased towards the reflected sounds to create the illusion of a more diffuse sound field and minimise the listeners ability to localise the speaker.

By contrast a bi-pole simply uses a matched dual driver array on opposing or angled cabinets sides to widen the natural dispersion of the speaker beyond what would be possible from a single direct radiating driver. This ensures sufficient dispersion is achieved over a short distance for any listeners sitting close to the speaker. However the bi-pole speaker remains a point source the same as a monopole, just with a wider dispersion pattern.

Personally I think if you follow Atmos' recommendation of having the surround speakers at ear level, and sit within, say, 6ft of the speaker, a bipole arrangement is almost essential to prevent the surround speaker drawing too much attention to itself.

Di-poles on the other hand I don't think have any credible place in a multi-channel speaker system (nor ever have). The way they are designed to work is a bit of a cheap parlour trick to my mind. They certainly have no place in an Atmos array where fairly precise imaging is required.

Tri-pole speakers are a bit of a unique case I think. They counter the null created by their opposing di-pole drivers with forward facing monopole drivers. Having owned MK tripoles I can attest that they are indeed very good, and create a nice diffuse rear surround field but addsome degree of localisation into the mix. That being said, I struggle to see their merits in an Atmos based system as the two elements would seem to be working against one another. As I have said before, I think they would operate much more optimally in a bi-pole arrangement - something that could be altered quite easily by simply swapping the connections over on the out of phase di-pole driver. Ultimately the proof would be in the testing in both configurations.
 
You have to remember how di-pole and bi-pole speakers create their dispersion pattern though Steve. They are very different and shouldn't be grouped together.

Di-poles, by design, create a null in front of the speaker with the aim of the listener being within that null. The ratio of reflected versus direct sounds that the listener hears is therefore biased towards the reflected sounds to create the illusion of a more diffuse sound field and minimise the listeners ability to localise the speaker.

By contrast a bi-pole simply uses a matched dual driver array on opposing or angled cabinets sides to widen the natural dispersion of the speaker beyond what would be possible from a single direct radiating driver. This ensures sufficient dispersion is achieved over a short distance for any listeners sitting close to the speaker. However the bi-pole speaker remains a point source the same as a monopole, just with a wider dispersion pattern.

Personally I think if you follow Atmos' recommendation of having the surround speakers at ear level, and sit within, say, 6ft of the speaker, a bipole arrangement is almost essential to prevent the surround speaker drawing too much attention to itself.

Di-poles on the other hand I don't think have any credible place in a multi-channel speaker system (nor ever have). The way they are designed to work is a bit of a cheap parlour trick to my mind. They certainly have no place in an Atmos array where fairly precise imaging is required.

Tri-pole speakers are a bit of a unique case I think. They counter the null created by their opposing di-pole drivers with forward facing monopole drivers. Having owned MK tripoles I can attest that they are indeed very good, and create a nice diffuse rear surround field but addsome degree of localisation into the mix. That being said, I struggle to see their merits in an Atmos based system as the two elements would seem to be working against one another. As I have said before, I think they would operate much more optimally in a bi-pole arrangement - something that could be altered quite easily by simply swapping the connections over on the out of phase di-pole driver. Ultimately the proof would be in the testing in both configurations.

My apolologies for reviving such n old thread.

Wookii- Where are your (7) SR3’s mounted? I have a 7.1 system with my back wall 14ft behind my single row of seating. I currently have my rear surrounds (LR3’s) on stands at the back wall. How would SR3’s in bipole mode perform mounted on the back wall for these rear surrounds?

My wife doesn’t like the way the stand mounted speakers look in the back of our room. Wall mounted SR3’s would be more acceptable. I don’t want to put aesthetics over performance though.

Thanks in advance!
 

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