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Discussion Starter · #1 ·
Hi,


anybody knows how side/dipoles + rear/monoploes are supposed to be wired phase-wise, as suggested / requested by THX2?


Should it be:


.+....+....+.

.................

.................

+.............+

-..............-

...+......+...


or should it be:


.+....+....+.

.................

.................

-...............-

+.............+

...+......+...


(hope this is understandable :rolleyes: )


Any thoughts? Or anybody using this configuration, how does it sound best?


Many thks,


Hugo :confused:
 

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Hugo:


I would think that Philip Brandes' advice


Placement of Dipoles for EX/ES
still applies.


That is, the side surrounds should be in phase with the front speakers.


I'm using this configuration with diploes on the side and three monopoles (same back channel) in the back. It sounds good to me.


I'm not sure whether the Pioneer Elite's new Ultra2 receivers have been released yet in very limited locations, but they will be the first to have THX Advanced EX (Ultra2 surround).


Larry
 

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Discussion Starter · #3 ·
Thks Larry,


I read Philipp's recommandations which tended to have everything in-phase "one regarding the adjacent other".


But with this dipole/monopole mix, something HAS to be out of phase. But where?


Hugo
 

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Hugo:


The way I interpret this is your first diagram is correct. Only the rear facing drivers in the dipoles are out of phase with the front speakers.


Larry
 

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Discussion Starter · #5 ·
Larry,


It also seems to me the right way to go, so how does it sound?


How large is your listening room as you have 3 rears?


Do you have any seat close to a side, to the rear?


In that case is ther any "significal" difference in left/right positionning with the center / prefered seat?


Which type of processing do you use?


I know, makes quite a lot of questions...


So Thks,


Hugo
 

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Since you would normally listen to dipole surrounds from within the "null" of the dipoles and thus hear only diffuse or reflected sound, the absolute phase of the speakers has little impact. However, when THX checks the electrical phase of dipoles, they do so by looking for a + air pressure at the forward facing side of the speaker when a + DC voltage is applied. Therefore, the + side of the dipole should face forward.


One note. Some THX approved dipoles are asymmetrical in frequency response (front and rear facing arrays have different responses). On these dipoles, the speakers will have directional indicators.


Rear monopoles should be in phase with the front speakers. Rear dipoles, if on the back wall should also be in phase, although for THX Surround EX systems, I recommend using only 1 dipole in the center of the rear wall, if you are using them at all.
 

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Hugo:


I guess like most folks on this forum I continue to experiment. As I mentioned previously, my current arrangement sounds fine although I've never had back dipoles to compare with. With the THX folks now recommending back monopoles and people like Philip, whose opinion I respect, using back monopoles, its not likely I'll be changing anytime soon.


Click on my signature and you can see my current set-up. It has a scale drawing of my layout, listing of equipment, wiring diagram and pictures.


The reason for the three speakers is more as a result of upgrading my center and surround speakers and wanting to put them to use, rather than the size of the room. As you can see from the diagram the room is 13.5' x 24'. Its adequate in size, but not huge.


As you can also see my home theater has two rows of seating, a sofa located relatively close to my HDTV, and two sets of loveseats in the back row, equipped with tactile transducers. I find my preferred seating position varies by what I'm watching and whether I'm more interested in optimal viewing versus sound.


This of course is a personal preference issue, but when I'm watching high definition, generally I like to sit closer (on the sofa) to get the full effect of the higher resolution. If I'm watching a movie with aggressive surround and deep base, I'm definately going to be strapped into one of the loveseats to get shaken by the tactile transducers and to get more enveloping surround effects. When I sit on the loveseat I sit in a postion closer to the center of the room. To be honest with you I haven't spent much time in the seating position closest to the side surrounds to judge the difference in sound. I'll make a point of experimenting a little in the future.


I'm currently using a SMART Circle Surround 3X Jr., but I'm considering a used Lexicon MC-1 and some Parasound mono blocks for the back surrounds. I've read posting of folks using both surround processors together, I'm sure this might be a bit controversial for Lexicon purists, but if I ever get a Lex, I'd probably experiment with it.


Larry
 

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Hugo:

You should use the setup in your second diagram--i.e., the forward-firing drivers in the side dipoles should be in phase with your fronts. The front soundfield is the critical area where phase anomalies are most noticeable. I use monopole rears in my setup with no ill effects that I can detect.


Larry:

The problem with trying to combine the SMART device with the Lexicon is that you're then using the SMART on the Lexicon's processed rear channel content rather than the encoded surround channels it was designed to work with. The Lexicon rears have been through additional processing which changes the encoded phase relationships on which the SMART depends for accurate decoding. While you will hear sounds from an additional speaker (which may be pleasurable), those sounds will not be integrated with the other surrounds in a coherent way.


Cheers,

Philip Brandes
 

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Discussion Starter · #9 ·
Larry,


Thanks for your input. I went to your link and congrats... VERY nice. I'm a bit "envious" as my/our own dedicated room is much smaller as it is "in-phase" with the European standards...


Anyway I'm in a process of changing my current installation consisting of a Sony STR DA50ES + 5 Triangle Comete identical French brand nearfield monitor-like small speakers.


This is hooked to a JBL Pro 4645c Sub + QSC DCA1222 bridged mode + Behringer Feedback Destroyer. This sub may be overkill, but it was bought never to reach any acoustical limit and it does it's job "the professional way" + it has fine blending (strange enough, but a fact) with the Triangle(s).


So for amplification I'm looking towards the new Pioneer offering (VSA AX10 in Europe) as it has 7 channels of amplification (+ no noisy fan) + THX2 + this "automatic" calibration 9 band parametric equalizer on all channels including .1 . And this is important for me as the BFD is an EXCELLENT product, but I'm not quite sure I got the equalization just 75% right using the Tandy/RS level meter + Excel...)


For loudspeakers, even if I/we (wife) adore those Triangle Cometes' with their "fast" reproduction "full of life", I think that the next ones will be KEfs'. Though my question concerning dipoles as I'm thinking of KEF TDM 34DS as sides and Q15.2 as rears + 3 identical Q35.2 at the front.



Philip,


It is my understanding from what you wrote in your post that you are referring to this arrangement:


.+....+....+.

.................

.................

+.............+

-..............-

...+......+...


in fact it is the FIRST listed and not the second as posted, it might be confusing for certain people.


Anyway many thanks to you both for your helpful comments.


Have a nice Sunday,


Hugo
 

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Quote:
Originally posted by Hugo S
Larry,


Thanks for your input. I went to your link and congrats... VERY nice. I'm a bit "envious" as my/our own dedicated room is much smaller as it is "in-phase" with the European standards...


Anyway I'm in a process of changing my current installation consisting of a Sony STR DA50ES + 5 Triangle Comete identical French brand nearfield monitor-like small speakers.


This is hooked to a JBL Pro 4645c Sub + QSC DCA1222 bridged mode + Behringer Feedback Destroyer. This sub may be overkill, but it was bought never to reach any acoustical limit and it does it's job "the professional way" + it has fine blending (strange enough, but a fact) with the Triangle(s).


So for amplification I'm looking towards the new Pioneer offering (VSA AX10 in Europe) as it has 7 channels of amplification (+ no noisy fan) + THX2 + this "automatic" calibration 9 band parametric equalizer on all channels including .1 . And this is important for me as the BFD is an EXCELLENT product, but I'm not quite sure I got the equalization just 75% right using the Tandy/RS level meter + Excel...)


For loudspeakers, even if I/we (wife) adore those Triangle Cometes' with their "fast" reproduction "full of life", I think that the next ones will be KEfs'. Though my question concerning dipoles as I'm thinking of KEF TDM 34DS as sides and Q15.2 as rears + 3 identical Q35.2 at the front.



Philip,


It is my understanding from what you wrote in your post that you are referring to this arrangement:


.+....+....+.

.................

.................

+.............+

-..............-

...+......+...


in fact it is the FIRST listed and not the second as posted, it might be confusing for certain people.
Yes...I lost track of which was on top by the time I read through the thread. Thanks for clarifying.


Cheers,

Philip Brandes
 
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