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post #1 of 18 Old 05-05-2012, 06:05 AM - Thread Starter
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in a 5.1 setup if the surrounds are going to be less than 2 feet from the rear wall, (not that 2 feet is the standard, just that's how close they will be in my situation) that I should use bookshelves or satellites as opposed to bipole, dipole, etc.?
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post #2 of 18 Old 05-05-2012, 09:23 AM
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I'm no expert, but I just upgraded my monopoles for polk fxia4s in the same situation and there is a huge improvement.

I am still playing around with orientations but right now I have them set up right in the corners so that the speakers are facing each other behind the listener and the other two face forward in bipole mode. It was suggested in one article that I am trying to find again to post here.

But placed one foot from the back wall on the sides sounds way more immersive than monopoles but I haven't done a direct comparison to the corner placement yet with the same scenes of a bluray.

Found it....

This is the thread, hope it's ok to link to another forum.
http://forum.blu-ray.com/showthread.php?t=66471

i am comparing between the two placements below in bipole mode. Both, however, sound way better than the monopoles. But in my placement one speaker is about twice as far from the listener than the other and doesn't work well in dipole mode. So bipole it is for me.
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post #3 of 18 Old 05-05-2012, 11:03 AM - Thread Starter
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I don't know if this matters in my situation but the surround speakers will be to the sides of the listener as opposed to being behind the listener. I thought with the speakers being so close to the back wall there would be too much reflection if I used bipole or dipole. I really don't understand the whole concept of bipole, dipole and under what conditions they should be used.
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post #4 of 18 Old 05-05-2012, 11:14 AM
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Dipoles work well when they are directly inline with and 2-3 feet above your listening position on the side wall. In fact, they are MEANT to be placed directly inline with you on side walls. I tried mine like that and it sounds great. Very spacious. BUT, for me one speaker has to be twice as far away than the other and no matter how loud I turned the far channel it didn't sound equal. In bipole mode I could easily match the levels for the difference in speaker distance.

I think you should be able to find a position that either dipole or bipole would work well since we are in similar situations and they sound great to me. I just need to do some direct comparison testing to decide on the final permanet mounting point.

Are you looking at speakers that are dipole/bipole switchable?
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post #5 of 18 Old 05-05-2012, 11:16 AM
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Quote:
Originally Posted by sfeldman721 View Post

in a 5.1 setup if the surrounds are going to be less than 2 feet from the rear wall, (not that 2 feet is the standard, just that's how close they will be in my situation) that I should use bookshelves or satellites as opposed to bipole, dipole, etc.?

heck no to the bookies. l just made the switch to di/bipole speakers over a month ago and the versitility and open sound field of them are, IMO, the way to go.

For your application, you might want to use dipole, where the opposing tweeters fire in alternating sequence, where bipole fires simultaneous

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post #6 of 18 Old 05-05-2012, 12:56 PM - Thread Starter
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See I thought with the tweeter being literally no more than a couple inches from the rear wall and facing it that that would create a problem. But you guys say no, so I guess I should look at bipole/dipole.
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post #7 of 18 Old 05-05-2012, 01:16 PM
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I guess I'll have to be the voice of dissent here because I always prefer monopoles for the surrounds.

Dipoles are very effective in what they do, producing what sounds to me like a broad and distant wall or spread of sound, but the quality of the sound is, to my ears, very poor, especially for directional/panning effects and music that may be present in the surround channels at times. I liked dipoles back in the Dolby surround and DPL days because they took a monaural, relatively low-fidelity surround channel and made it sound so much more spacious and atmospheric, but in my view soundtracks have fundamentally changed with regard to the now multiple surround channels (even old Dolby Stereo soundtracks when decoded by DPL II) that often contain phase and spacial effects mixed right in.

Bipoles sound much more like monopoles to me, but there is still too much reflected sound for my taste, and I don't like how some of the sound comes from in front of the viewing positions. If I wanted a similar spacial effect without the sound coming from in front, I could always angle a monopole toward the back anyway, but I still think that the surround channels sound best with the monopoles directed straight across the room, maybe just slightly behind the viewers, if anything. Additionally, whenever the viewers are close to a back wall, the reflected sound from that wall (using monopoles) seems to improve the surround field without sacrificing much fidelity; not that the latter is as critical for the surround channels as it is for the front channels, but I'll take all I can get.

And while not everybody cares about multichannel music, monopoles are most definitely the best at reproducing the music as intended, with significantly better fidelity in addition to matching what is heard in the studio.

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Originally Posted by Geoff4RFC View Post

heck no to the bookies. l just made the switch to di/bipole speakers over a month ago and the versitility and open sound field of them are, IMO, the way to go.

I don't have a problem with anything you said here because obviously we're all different, and there are always going to be various compromises in any home theater.

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Originally Posted by Geoff4RFC View Post

For your application, you might want to use dipole, where the opposing tweeters fire in alternating sequence, where bipole fires simultaneous

Actually, bipoles--in the context of home theater--are pretty much two monopoles in a single cabinet pointing in two different directions (in order to get reflections from both sides of the wall they're mounted on), while dipoles--once again in the context of home theater--are similar except that the polarity of one of the monopoles is reversed (or it could be a true open-baffle dipole speaker that produces the same effect, but I haven't seen many of those), which cancels nearly all of the direct sound so that their output is dominated by two reflections of opposite polarity.
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post #8 of 18 Old 05-05-2012, 02:17 PM
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Here's one more vote for the dipole/bipole solution. I'd never go back to a mono-pole speaker for surrounds.

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post #9 of 18 Old 05-05-2012, 04:01 PM
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For what it's worth, this is my present setup:

room: 20ft long, 16ft wide
front 3 speakers:
KEF Reference 104/2 mains, KEF 200C center
Surrounds:
Polk FXi3 bi-poles on rear wall.

System is 5.1 at present. I have a second pair of FXi3s, that if I should go to 7.1, will be set to di-pole mode, and placed along the side walls, and most likely at head level, or a few feet above, while the back surrounds will remain as bi-pole mode, against (hung on) the back wall as shown:





Personally in a smaller room like mine, I prefer the di/bi-pole setup to direct drivers for surround. Just about all surround encoded data sent to the rear speakers is ambient noise.. tire screeches, gunshots, crowd noise.. sounds I'd rather have dispersed and spread out anyway.

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post #10 of 18 Old 05-05-2012, 07:46 PM
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Two of the replies here mention Polk FX series surrounds. I had voiced my opinion earlier but I'll elaborate.

I've had Polk Monitor 30, 40 and 70 in the surround spot and finally ended up with the 40's sounding best to me.

I've upgraded to the FXiA6 and so far, is the best move I've made to date.

I have them mounted on stands to the sides of the listening position and employ the bi-pole setting. This gives me a 360 degree sound field and for whizzing bullets, flying jets, speeding cars, and as Glasswolf mentioned, just about anything you can get from ambient input, these speakers put you right in the middle of the action.

In case anyone is interested, here's a little education on Di/Bipole speakers and possible execution.
http://www.polkaudio.com/education/s...uestion_num=45

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post #11 of 18 Old 05-05-2012, 08:46 PM - Thread Starter
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Ok but in none of these examples does the surround (bipole/dipole) speaker, when mounted to the sides of the listening position, also have it's back side tweeter, or tweeter and mid range if it's a 5 way, right up against a back wall and that would be my situation, which is why I'm under the assumption that bipole or dipole won't work for me. Someone tell me I'm wrong and by all means I'll then consider bi/dipole.
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post #12 of 18 Old 05-05-2012, 09:45 PM
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I personally chose two pair of FXi3 speakers because I got them for a song from Polk as refurb speakers.. got em, looked brand new to me. I wanted the KEF Reference TDM34DS di-poles, but they are nearly impossible to find now, and I'm not sure the current incarnations of their "DS" line of Ref speakers would be well-matched to my system, nor are they really within my price range, at around $3,000/pair.

That said, what I didn't note, was that prior to my current setup, in my current home, I was in a much larger home, wehre I had a lot more room to play with speaker positioning, and used one pair of the bi-pole speakers as back surrounds, mounted higher on the wall as shown in the above pics, and used a matching pair of the same speaker, set to di-pole, on either side of my loveseat, used as the central position in front of the screen, about 4 feet away from each side or arm rest of the couch, on 36" Sanus natural foundation stands. They worked very well for 7.1, and I at no time felt a desire to swap them for a studio-monitor type bookshelf pointsource speaker instead of what I have.

If it will work in your situation, depends on a lot of factors. power applied, speakers chosen, room acoustics and treatment, source material you're viewing, and so forth. I can't tell you for sure what will sound best to your ears, as that's purely subjective anyway, but for me it worked great.

Oh, also, the FXi3 is not a 5-way speaker, nor does it have any speakers on the back side of the enclosure, so I can't really offer you anything on that front.

This is the FXi3:


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post #13 of 18 Old 05-06-2012, 03:24 AM - Thread Starter
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Just so we're clear when I say back side I'm referring to the side of the speaker which would face my rear wall.
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post #14 of 18 Old 05-06-2012, 04:28 AM
 
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A quick tutorial on which to use. Speakers are application dependent and what works best will vary depending on the situation. Let's start with ideal.

Ideally, we would have identical mono-poles all around for every speaker. If your set up can work like this it is the way to go. The problem with monopoles for surrounds is we have multiple seats.

Let's say we have a narrow room and can only fit a row of 3 seats. The seats are near the wall and the surround speakers are 2 feet from the people sitting in the left and right seat. In this case only the center seat has good sound. The people on the left and right basically have a speaker in their ear which overpowers the other surround speaker and they do not get the envelopment the person in the center enjoys.

This is an application a di-pole and would work well. The null created by the di-pole help to create a more diffuse sound for all listeners. Di-poles really only work if the listener's are in-line with the speaker and in the null, if this can't happen don't use a di-pole. In a theater there are multiple side surrounds which make localization more difficult and create this diffuse sound.

The speaker placed a little further away a bi-pole might work well or even close to the listener might work depending on the design of the speaker. A Monopole works best when speakers can be placed at least 5 feet away. Some might say even further but it depends on seating and the room. Try to keep your seat to seat variation <3db. If you have mono-poles and your speakers are to the side and very close try aiming them at the ceiling or turn them around and aim it at the wall. These are some ways to diffuse a mono-pole. Another thing is to bring them behind the listeners on the side wall and aim them at the center listening position, this will help get them a further away and still get a good response which isn't too off axis for the speaker.

Bi-poles help with coverage and with 2 rows of seating are often a good bet. Ideally, in this situation you would have 2 sets of side surrounds but you have to add an amp and a processor so the proper level and delays can be set for each row. A little more complicated for most. If you place the speakers between the rows on the side wall so each row of seats has a similar sound level many mono-poles would not have a good off axis response and the listeners closest to the speakers would not be receiving good sound. A bi-pole can work well here so the listener's in each row get within the dispersion pattern of that speaker.

Speakers are really application dependent and their is no right answer on what's best between these speaker types. Use whatever works best for your situation.

Hope this helps.
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post #15 of 18 Old 05-06-2012, 11:01 AM - Thread Starter
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Quote:
Originally Posted by BobL View Post

A quick tutorial on which to use. Speakers are application dependent and what works best will vary depending on the situation. Let's start with ideal.

Ideally, we would have identical mono-poles all around for every speaker. If your set up can work like this it is the way to go. The problem with monopoles for surrounds is we have multiple seats.

Let's say we have a narrow room and can only fit a row of 3 seats. The seats are near the wall and the surround speakers are 2 feet from the people sitting in the left and right seat. In this case only the center seat has good sound. The people on the left and right basically have a speaker in their ear which overpowers the other surround speaker and they do not get the envelopment the person in the center enjoys.

This is an application a di-pole and would work well. The null created by the di-pole help to create a more diffuse sound for all listeners. Di-poles really only work if the listener's are in-line with the speaker and in the null, if this can't happen don't use a di-pole. In a theater there are multiple side surrounds which make localization more difficult and create this diffuse sound.

The speaker placed a little further away a bi-pole might work well or even close to the listener might work depending on the design of the speaker. A Monopole works best when speakers can be placed at least 5 feet away. Some might say even further but it depends on seating and the room. Try to keep your seat to seat variation <3db. If you have mono-poles and your speakers are to the side and very close try aiming them at the ceiling or turn them around and aim it at the wall. These are some ways to diffuse a mono-pole. Another thing is to bring them behind the listeners on the side wall and aim them at the center listening position, this will help get them a further away and still get a good response which isn't too off axis for the speaker.

Bi-poles help with coverage and with 2 rows of seating are often a good bet. Ideally, in this situation you would have 2 sets of side surrounds but you have to add an amp and a processor so the proper level and delays can be set for each row. A little more complicated for most. If you place the speakers between the rows on the side wall so each row of seats has a similar sound level many mono-poles would not have a good off axis response and the listeners closest to the speakers would not be receiving good sound. A bi-pole can work well here so the listener's in each row get within the dispersion pattern of that speaker.

Speakers are really application dependent and their is no right answer on what's best between these speaker types. Use whatever works best for your situation.

Hope this helps.

Thanks for the explanation and yes, it does help.
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post #16 of 18 Old 05-06-2012, 12:21 PM
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Quote:
Originally Posted by sfeldman721 View Post

Ok but in none of these examples does the surround (bipole/dipole) speaker, when mounted to the sides of the listening position, also have it's back side tweeter, or tweeter and mid range if it's a 5 way, right up against a back wall and that would be my situation, which is why I'm under the assumption that bipole or dipole won't work for me. Someone tell me I'm wrong and by all means I'll then consider bi/dipole.

Did you try clicking on the link I provided above this post of yours I'm quoting? It gives examples of both side and back wall.

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post #17 of 18 Old 05-06-2012, 04:58 PM - Thread Starter
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Quote:
Originally Posted by Geoff4RFC View Post

Did you try clicking on the link I provided above this post of yours I'm quoting? It gives examples of both side and back wall.

Actually yes I read the info on Polk's website. While helpful as far as determining whether I should be using dipole or bipole, I think I may have to just go with bookshelves or satellites. I can't do dipole because the speakers wouldn't be directly to the side of the listening position. Bipoles would require mounting on the back wall and I don't think I would be able to do that without changing a whole bunch of stuff in the room. Although using bookies (are direct radiating speakers the same thing as a monopole speaker?) may not be the ideal solution for movie theater like surround sound, that is the most likely course I'll take. Thanks everyone for imparting your knowledge on me. As always it is greatly appreciated.
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post #18 of 18 Old 05-06-2012, 08:20 PM
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Quote:
Originally Posted by sfeldman721 View Post

Actually yes I read the info on Polk's website. While helpful as far as determining whether I should be using dipole or bipole, I think I may have to just go with bookshelves or satellites. I can't do dipole because the speakers wouldn't be directly to the side of the listening position.

A guys gotta do what a guys gotta do, but I tell you, there's no "set in stone" way to do these types of speakers.

Mine are on stands to the side of the listening position, and mine are set to Bipole.

Just because you have them mounted in a specific area doesn't mean it has to be set to a specific function.

Here's the final sentence from the Polk site which IMO, sums it up; Polk f/x speakers give you the choice of either polar pattern so you can choose the one that's sounds best to you in your set-up.

This is pretty much the basis of all home theater applications, it's what sounds best to you

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