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Discussion Starter · #1 ·
What is everyone's opinion on rear speaker type: direct radiating or bipolar? I'm setting up a dedicated home theater room with a 7.1 system and need to buy some surround speakers. My room is 14' by 18' with the primary listening position about 6 ft off the back wall centered in the room. There will be a couch against the back wall since I'm doing tiered seating so I'm going with in-wall speakers for the rear. I'm definitely going bipolar for the sides, but I've heard differing opinions on the rear. Here's what I've got:


Receiver: Denon 3803

Front: DefTech BP8

Center: DefTech CLR2002

Sub: DefTech Powerfield 12


Staying with the DefTech theme, I'm considering the BPX or BP2X for the sides and either the UIW55 (direct) or UIWBP/A (bipolar) for the rear.


So, what do you think?


Thanks,

Frank
 

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The subject hs been covered loads of times before. Do a couple of searches.. "bipole" "dipole" and "tripole"

http://www.avsforum.com/avs-vb/showt...ghlight=bipole

http://www.avsforum.com/avs-vb/showt...ghlight=bipole

http://www.avsforum.com/avs-vb/showt...ghlight=bipole


and loads more.


All depends on room size & shape, location of sofa relative to side/rear walls, if several positions are close to the surround speaker(s), whether you prefer one type over the other (direct or non-directing) and whether music/movie preference.


Personally I prefer non-direct surround speakers (NHT dipole sides) haven't tried different types for rears though (found a pair of BP-2X's too) might consider these.


AFAIK someone (think THX) recommends Dipoles for sides, monopoles for rears..Dolby say all identical monopole speakers all round (but in a real world, home theatre installation this rarely works well IMO) unless you have a dedicated HT room.. even then I would still probably consider using tripoles for sides & back.
 

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Discussion Starter · #3 ·
There is some good info in those threads, but most of it applies to 5.1 systems or surrounds in general instead of specifically rear speakers.


Basically what I'm interested in is what other people have done with a similar setup - dedicated HT room, 7.1, primarily watching movies.


Anyone?
 

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Depends a lot on the room shape relative to the listening position. I have a rear wall well behind the listening position, and a recessed doorway in it. I use monopoles set high pointed at the listening position. I believe this allows some dispersion and reflection.


If the wall were much closer to the listening area, I think I'd go with a bipole or even dipole (still set high).
 

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I guess I qualify. All of my speakers are bi-polar except for the center. The mains and rears are front/rear-firing towers (fronts have powered subs built in), and the sides are trapezoids, wall mounted. (See below) I love 'em.
 

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I'm using direct radiating speakers for rear channel duty and am very pleased with the sound. Since they are behind me they are difussed enough for my taste. I say Bipole/Dipole on the sides and Direct for the rear channels.
 

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IMO, I think it has to do with the room, listening habits, and taste.


I prefer direct all around, but that is just me.


My listening habits in order are:
  1. 2 ch music
  2. multi ch music
  3. movies[/list=1]


    So I guess I am of little use to you. :D
 

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Great review. And basically covers my own feelings to which type I prefer for surrounds (non direct) After borrowing bipole & dipole speakers, and comparing with monopole's (In a 5.1 system) I settled for dipoles. Perhaps if the bipoles were better quality/high output I would also consider them too on the back wall. Currently upgraded to 7.1, and still using the dipoles as sides.


Of course tripoles can also be considered as well (dipole's diffuse sound with some direct-sound like monopoles)


I think people prefer monopoles as they're cheaper (less drivers) than bi/di/tri. Cheapest is not always the best solution ;-) Just because Dolby recommend identical monopole speakers all-round does not mean they're correct. For cinemas- yes (with 6-off pairs of monopoles with complicated surround sound processing) but for the home it's totally different.


I don't like "in yer face" surround effects-obvious panning from front to back. There is still sound information reproduced, but not like someone shouting in the street "HEY YOU" which causes you to look.
 

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I can second below, works very well in my room.


The other thing I have wondered about is some surround speakers designate a left and right channel because the way the drivers are positioned. I have to wonder if you matched your rear centers to this configuration what the result would be.

Quote:
Originally posted by Frank Zimkas
I'm using direct radiating speakers for rear channel duty and am very pleased with the sound. Since they are behind me they are difussed enough for my taste. I say Bipole/Dipole on the sides and Direct for the rear channels.
 

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Quote:
Originally posted by DRS
I wish they would have tried dipoles on sides and two monos in rear...


FWIW I hesitate to buy another pair of dipoles for the rear for the reason I list above.
They did:

"next, we used monopole rear speakers with dipole sides;"


Rear dipole placement (just substitute with your brand):


 

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Oops, I was just looking at the two diagrams which indicate all monos vs. all dipoles. I'll have to actually read next time ;)


"next, we used monopole rear speakers with dipole sides..."
 

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I finally had a chance this week to read the whole article (not that it was that long or anything but...) and I have a hard time understanding the following recommendation:


"All things considered, I'd go with the monopole side surrounds and dual dipole back surrounds, as this setup offers more flexibility."


Next to last sentence from here: http://www.hometheatermag.com/loudsp...25/index5.html


Of course you cannot take the statement out of context but given the article as a whole I still fail to understand the recommendation especially considering the amount of information that comes out of the side surrounds as compared to the read surrounds. In other words if you were to look at the amount of information that comes out of the rear centers over the length of an entire movie I would be willing to bet it would be in the single digit percentage, why devote the better sounding bipoles to the channel that does not have that much info compared to the side surrounds? I do understand his point concerning the precedence effect (primarily/only hearing the nearest monopole speaker) so maybe it just depends on room configuration more than anything. All I know at this point is I am real tempted to go buy another set of (correction) dipole surrounds for the rear to test all of this out.
 

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FWIW here is an excerpt from a recent WSR article on the subject:


The Case For All-Matched Loudspeakers In Surround Sound


At Widescreen Review, we have long adopted the approach of identical front and surround loudspeakers. The reasoning is simple: to achieve optimal tonal matching. When loudspeakers in a surround system are identical, so are their sonic characteristics. This also means that the probability of being able to derive seamless, optimally immersive and precise imaging is much greater than other systems. While I have personally experienced this in our reference theatre with our top-flight Dunlavy Audio Signature Series SC-Vs, from experience I can also certainly vouch for this with substantially less expensive loudspeaker setups as well (including home theatre-in-a-box systems), simply because of the fact that all of the loudspeakers in those systems are identical.


The selection of all-matched loudspeakers essentially dictates the use of those which are direct-radiating, whether they be the conventional monopole, electrostatic, planar magnetic, or even bipole (with one of the radiating surfaces directly facing the listener). The “movie theatre†approach (Figure 1) typically calls for dipole loudspeakers for the surrounds, for which the sound is indirectly radiated toward the listener with the help of boundary reflections.


Direct radiators are widely being favored by those who work with multichannel music, as well as HDTV audio and gaming. My belief in this has to do with the seamless soundstaging that is possible to create a very compelling sense of immersion. I have always determined that the use of dipoles, while effective in creating that sense of nebulous spaciousness like in a movie theatre, compromises the perception of being truly engulfed in a three-dimensional listening space.


The use of identical loudspeakers goes back to the days of quadraphonic sound in the 1970s. While many tend to dismiss quad stereo as laughable to its commercial failure, it should be noted that many recording engineers and producers who have and are continuing to pioneer surround sound music today have their roots in quadraphonic stereo. These and others who have worked in this four-channel domain know full well its potential for a wonderfully immersive listening experience. The problem was that back then, the fantastic results experienced during production, and monitoring could not be satisfactorily translated to the consumer.

http://www.widescreenreview.com/wsrmmbr/attyht1.lasso


The article goes on about optimal placement, interesting but not practical unless you never have people in your HT.
 

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That's what I thought too....dipoles were created for 5.1 channels and is also recommended if you are using a THX system. If you are going to use multichannel music too, then one would need something where you can switch the dipole into a monopole. The bipole design seems to be a compromise of both design such that a speaker need not have to employ a dipole/monopole switch.


In a test done by Home Cinema Choice of 6 surrounds (and also 6 centers), the ENERGY CONNOISSEUR SERIES C-R3 came out on top with the MIRAGE OMNISAT coming 2nd which is an omnipolar design. The expensive tripole (allows you to use both dipole and monopole simultaneously) designed M&K SS-150THX only managed 4th. It would be nice to have the PARADIGM ADP-470 reviewed too just to compare how its own dipole/bipole design would fare against the ENERGY.


Surround speakers


1. ENERGY CONNOISSEUR SERIES C-R3

2. MIRAGE OMNISAT

3. MISSION M51

4. M&K SS-150THX

5. FOCAL.JMLAB COBALT SR800

6. MISSION 78DS


"With a flattened hemispherical cross section, and a range of colour schemes, this compact speaker will disappear in many settings, thanks in part to a novel 'soundfield management system'. The proposition underpinning this uniquely configured loudspeaker is summed up by Energy as 'perfect sound in a less then perfect room'. Leaving out the hyperbole, the speaker can be adjusted to suit different acoustic surroundings. The system uses a centrally-mounted bass and tweeter, and two side-firing midrange units, which can be driven in phase (bipole) or out of phase (dipole), with a level control, adjusting midband output to tastes - or to match the other speaker in the pair.


Like other models in the range, the C-R3 draws on technology originally developed for the Veritas range, and of course it is approximately timbre matched to the rest of the Connoisseur range. The soundfield management options are extremely effective, and the system can give a relatively direct, or a relatively diffuse soundfield, with a wide dispersion pattern ensuring negligible changes in dispersion from different listening positions. The voicing is very open and out of the box, with low colouration levels, and the single tweeter means no phasiness, which can be a problem with some designs."


http://www.homecinemachoice.com/test...roundSpeakers/
 
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