Bipole or Monopole for Rear Surround in 5.1

[echoesian]

Due to my living hall layout, I cannot place the surround at the sides, the only choice is to put them on the rear walls. Bipole or monopole would be better
in this situation?

 

[3db]

Due to my living hall layout, I cannot place the surround at the sides, the only choice is to put them on the rear walls. Bipole or monopole would be better in this situation?

I think it boils down to a personal choice. SOme people prefer dipoles, others prefer monopole. If you plan on using the system for multichannel music such as on SAC or DVDA, then monopole would be the preferred choice.

 

[j_garcia]

Agreed, it is a personal preference. I prefer monopole.

 

[sholling]

What I don't see in the drawing are side surrounds. Anyway I agree with the others - it's personal preference. There are situations where I sometimes prefer bipolar speakers such as when the surrounds are too close due to a narrow room. However I always prefer monopoles for music such as concert DVDs etc.

 

[ChunkyDark]

What about ceiling mounted brackets or stands for the the surrounds?

 

[AJinFLA]

Bipole (or dipole). IMHO, It is better to have the surround channel less localizable, even for MCH music, as well as movies. Your focus should be forward, at the screen (movies) or front stage (band), with the surround effects ancillary, an enhancement of what is occurring in front of you. If there is a mix that requires localization, such as an instrument being played behind you, it's pure gimmick. That's why those things failed. The novelty wears of quickly and you realize that no concert or music event you went to had you sitting inside the band, unless you were playing, rather than observing.
Btw, bipoles add spaciousness and some diffusion, but on say a MCH music soundtrack, you can still localize them...if that is your desire. It's not a black and white situation, more like black/gray.

cheers,

AJ

 

[echoesian]

As I know the bipoles are suitable more for ambience sound.. but how about the feeling of sound movement across your ear from left to right like what the monopoles do. Is this effect is achievable in bipoles?

 

[markw]

You should be asking yourself what the systems main usage will be...

As I know the bipoles are suitable more for ambience sound.. but how about the feeling of sound movement across your ear from left to right like what the monopoles do. Is this effect is achievable in bipoles?

... and take it from there.

To be able to track the position of (localize) sounds you need as close to a single point source as possible. To create an enveloping, amorphous aura of total immersion, you want as many point sources as possible.

Depending on what you want, either type of speakers will "work", but so does plain water in breakfast cereal. It just might not have quite the effect you had hoped for.

 

[3db]

As I know the bipoles are suitable more for ambience sound.. but how about the feeling of sound movement across your ear from left to right like what the monopoles do. Is this effect is achievable in bipoles?

I suggest you listen to a friends system to see how their surrounds work for you. I use monopoles and I love the ambien sound I get from them. A real good DVD for this is Master & Commander, at the start of the movie were the activities takes place in the bowls of the shipbefore they engage the French ship. Use that as your reference DVD.

 

[AJinFLA]

As I know the bipoles are suitable more for ambience sound.. but how about the feeling of sound movement across your ear from left to right like what the monopoles do. Is this effect is achievable in bipoles?

Yes. Keep in mind that the typical "bipole" surround speaker is simply 2 monopoles at a 90 degree angle, something like this. When you place such a speaker in the corner like you have diagrammed, you get a direct sound from the driver set facing the couch (and a portion of a the 2nd set mixed in), as well as reflections from both sets off walls. With a monopole in the same position, you get the same mix of direct sound and reflections off the wall, it's just that the percentage of reflections is lower than the bipole. Both will be somewhat diffuse/less localizable because of the early reflections, especially behind you, where you don't hear as well as in front of you, but the bipole will be more diffuse and more spacious because of the higher percentage of reflected sound, having a larger area behind you of where the "effect" might be coming from. This tends to work better for movies, less so for MCH music. But who wants to hear a guitar or violin playing clearly behind you? What percentage of attended music events does that recreate for you?
Both will "work", one will be more diffuse/spacious than the other (and possibly be able to play a bit louder due to the 2nd set of drivers). Perhaps it comes down to price/aesthetics after that.

cheers,

AJ

 

[echoesian]

Yes. Keep in mind that the typical "bipole" surround speaker is simply 2 monopoles at a 90 degree angle, something like this. When you place such a speaker in the corner like you have diagrammed, you get a direct sound from the driver set facing the couch (and a portion of a the 2nd set mixed in), as well as reflections from both sets off walls. With a monopole in the same position, you get the same mix of direct sound and reflections off the wall, it's just that the percentage of reflections is lower than the bipole. Both will be somewhat diffuse/less localizable because of the early reflections, especially behind you, where you don't hear as well as in front of you, but the bipole will be more diffuse and more spacious because of the higher percentage of reflected sound, having a larger area behind you of where the "effect" might be coming from. This tends to work better for movies, less so for MCH music. But who wants to hear a guitar or violin playing clearly behind you? What percentage of attended music events does that recreate for you?
Both will "work", one will be more diffuse/spacious than the other (and possibly be able to play a bit louder due to the 2nd set of drivers). Perhaps it comes down to price/aesthetics after that.

cheers,

AJ

Actually I'll use it for movies more than music listening maybe 80/20. So, bipoles is the way to go... ? Yes, I agree the bipole is much more expensive than the monopole.

 

[j_garcia]

Yes. Keep in mind that the typical "bipole" surround speaker is simply 2 monopoles at a 90 degree angle, something like this. When you place such a speaker in the corner like you have diagrammed, you get a direct sound from the driver set facing the couch (and a portion of a the 2nd set mixed in), as well as reflections from both sets off walls. With a monopole in the same position, you get the same mix of direct sound and reflections off the wall, it's just that the percentage of reflections is lower than the bipole. Both will be somewhat diffuse/less localizable because of the early reflections, especially behind you, where you don't hear as well as in front of you, but the bipole will be more diffuse and more spacious because of the higher percentage of reflected sound, having a larger area behind you of where the "effect" might be coming from. This tends to work better for movies, less so for MCH music. But who wants to hear a guitar or violin playing clearly behind you? What percentage of attended music events does that recreate for you?
Both will "work", one will be more diffuse/spacious than the other (and possibly be able to play a bit louder due to the 2nd set of drivers). Perhaps it comes down to price/aesthetics after that.

cheers,

AJ

In a properly setup all monopole system it works extremely well. Proper calibration and aiming are critical for it to sound right. My surrounds are to the sides and behind aimed toward the front of the room, toed in from the wall. The right surround doesn't have an immediate wall so the first reflection is pushed out. The left side is near the wall and though the first reflection is muted by heavy curtains, it still ends up having to be notched down 1dB compared to the right. For m/c music, it sounds excellent and for movies, I don't notice any issues with them being diffused enough. I don't have an immediate right rear wall, and on the left is 20 ft of vertial windows which is why side surrounds won't work in my current room. I still prefer monopoles, though this was driven by music for me, movies still enjoy the same benefits.

That is not to say that bi/dipoles aren't good, they just aren't my preference. The manufacturer of my speakers doesn't make bi/dipole, only an upward facing version that uses the ceiling to create the diffusion. Since my ceiling is high and angled, those won't work for me either.

 

[AJinFLA]

I still prefer monopoles...

Ok.

....though this was driven by music for me, movies still enjoy the same benefits.

What benefits?
The "benefit"....of you preferring them?

That is not to say that bi/dipoles aren't good, they just aren't my preference.

I thought we had already established that?

The manufacturer of my speakers doesn't make bi/dipole, only an upward facing version that uses the ceiling to create the diffusion.

Ok JG, so what non-monopole did you use, to establish your oft-stated preference for monopoles??

Since my ceiling is high and angled, those won't work for me either.

Pray tell, what does this, or your preferences, etc....have to do with the OP?

 

[j_garcia]

Not sure what you are getting at?

What benefits?
The "benefit"....of you preferring them?

The benefit of a properly setup system means that it sounds good whether I am watching a movie, listening to multichannel music or playing a game on the PS3.

Ok JG, so what non-monopole did you use, to establish your oft-stated preference for monopoles??

Paradigm 170s and studio 370s, AV123's older ELTs, Aerials in a dedicated theater. What comparisons have you done?

Pray tell, what does this, or your preferences, etc....have to do with the OP?

Frame of reference? Same relevance as anything you've added to the thread.

 

[AJinFLA]

The benefit of a properly setup system means that it sounds good whether I am watching a movie, listening to multichannel music

So the "benefit" of a monopolar rear channel over a multipolar...is that it "sounds better"...to j garcia. Ok.
Can you explain the benefit of greater localization on MCH music? What is back there in particular that need to be localized? Can you give an example of music or a particular recording that highlights the advantage of the monopole rear channel?

 

[AJinFLA]

Actually I'll use it for movies more than music listening maybe 80/20. So, bipoles is the way to go... ?

The bipole will be less localizable and more spacious than the monopole. So it's up you to decide which will fit your need. A less localizable/more spacious an immersive "enhancement" of what is happening in front of you on the screen, or a more localizable/less spacious effect, like hearing a violin behind you on music, or so you can pin point someone sneaking up on you in a video game, like j-garcia needs to have. Hard to say which you may prefer.

Yes, I agree the bipole is much more expensive than the monopole.

Price is always an issue, though the ones I linked were $80..per pair.

cheers,

AJ

 

[jeffsg4mac]

I had a mirage system with dolby pro logic and the bipole rears were great. When I moved to a true 5.1 the dipoles just never sounded quite right. You have to look at it like this. In a 5.1/7.1 recording the sound engineer( if he or she is good) is trying to place certain sounds in the space at certain 3D points in the room to try and match the visual cues on screen. For this reason dipole/bipoles just don't work as well. You don't want diffuse sounds when you are trying place a sound somewhere in a 3D space. That is exactly why Bose direct reflecting speakers were/are so horrendous. Sure the 901/801/601's had a huge soundstage, but instrument placement with them was/is non existent when you go bouncing stuff off the walls.

 

[AJinFLA]

I had a mirage system with dolby pro logic and the bipole rears were great. When I moved to a true 5.1 the dipoles just never sounded quite right. You have to look at it like this. In a 5.1/7.1 recording the sound engineer( if he or she is good) is trying to place certain sounds in the space at certain 3D points in the room to try and match the visual cues on screen. For this reason dipole/bipoles just don't work as well. You don't want diffuse sounds when you are trying place a sound somewhere in a 3D space. That is exactly why Bose direct reflecting speakers were/are so horrendous. Sure the 901/801/601's had a huge soundstage, but instrument placement with them was/is non existent when you go bouncing stuff off the walls.

The Bose is poor for many reasons, but it is a highly asymmetric bipolar, IIRC, a 30/70 (rear) sound power split (or something along those lines). It's a rather poor example to use as Exhibit A.
Try fast forwarding into the present and listening to a high performance more symmetric bipole/dipole like DukeL's Audiokinesis offerings or Linkwitz Orions...then tell me if your monopoles are anywhere near as capable at 3D space apparent source placement .
WRT to the dipoles(?) not sounding right when you switched to true 5.1, was it radiation pattern per se, or the system setup, that caused the perceived deficiency?

cheers,

AJ

 

[AJinFLA]

Btw, not an AES paper by a long stretch, but I did find this "blind" comparison WRT to monopole vs multipole surround.
I also perused some manufacturer sites that, as a DIYer, I generally have little interest in, but whose products I recognize as very well engineered (and the beneficiary of scientific research by organizations such as the NRC), such as Revel, KEF, Paradigm (Sig), PSB (Platinum), etc.
They all build specifically designated "surround" models...in dipole or bipole format.
I find it strange that, as for profit companies, they would incur the extra cost of extra drivers in their designated surround models, in their reference lines, especially if they need not be multi-polar for best perceived performance.
But I suppose that may be just their preference .

cheers,

AJ

edit: and another

 

[j_garcia]

Usually you are kind of useful, but in this thread you are kind of just being difficult. You didn't answer my question about what comparisons YOU have done, not what others have done. I've done my own comparisons and come to my own conclusion. The EXACT reasons that you give for diffused sound are what I don't like about multipolar surrounds. The directionality is what makes it work.

Yes, for movies there are things that are going on back there that are supposed to be diffused sounding, and they ARE. For music, when they place an instrument in a particular speaker, that is where it should sound like it is coming from, not EVERYWHERE behind you. When things pan around the room, as man multichannel audio discs do, I want it to actually sound like it is moving around, not just blending in behind me. Audio discs off the top of my head that do this: Roxy Music's Avalon SACD, Steve Miller Band's Fly Like an Eagle, Pink Floyd's DSotM SACD. All have slow pans from speaker to speaker or audio that intentionally uses all speakers at the same time. On Avalon, the soundstage is broken up with the supporting singers in the rear and it works surprisingly well. Every Porcupine Tree DVD-A has sounds in specific speakers. Eagles Hell Freezes Over - Seven Bridges Road has one voice in each speaker and it sounds amazing. Do you think they intended that track to be listened to with the two voices in the surrounds diffused? For movies, when a bullet flies from the back of the room to the front or vice versa, should it go from "somewhere" to sounding crystal clear? Not all sound in the surrounds is supposed to be diffused. I agree to disagree...

AFAIK, when m/c tracks are engineered, they are engineered on monopoles in a treated room, not bi/dipoles.