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REAR surrounds (for EX/ES) direct radiating or dipole?

Discussion in 'Speakers' started by MichaelDDD, Oct 26, 2003.

  1. MichaelDDD

    MichaelDDD Supporting Actor

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    Simple question. (Heh...as if there is one when it comes to speakers!)

    For the REAR surround speakers (for DD-EX/DTS-ES) are you supposed to have direct-radiating or dipoles?

    I currently have a set of Axiom QS-8s for my surrounds. Do I get another pair of them or a smaller set like the M2i?

    Thanks.
     
  2. Richard_B

    Richard_B Stunt Coordinator

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    It's all preference.

    If you think you are gonna be playing multi-channel music DVD-A or SACD then I would say to get the direct-radiating for the back and use the dipoles for the side surrounds on a 7.1 setup.
     
  3. Phil Iturralde

    Phil Iturralde Screenwriter

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    I followed the recommendation from Dolby Labs Listener's Guide to DD-EX website ...

     
  4. MichaelDDD

    MichaelDDD Supporting Actor

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    Thanks, Richard and Phil. [​IMG]

    Phil, what a reply! Complete with graphics and multi-colored text too! [​IMG]


    Gotta luv that. [​IMG] I do plan on checking out some DVD-A/SACD discs...but being that I already own one set of QS8s, I guess I'll be purchasing another. Thanks a lot!
     
  5. Edward J M

    Edward J M Cinematographer

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    Phil:

    I just love your posts. They are so....analytical. Graphics, color, flawless logic backed by self generated data. You're an asset to the forum.

    Anyway, FWIW, I run 7.1 with dipoles at the side and monopoles in the rear, but otherwise exactly like the DD-EX chart Phil provided.

    Probably more important than having identical speakers all around is having them timbre matched. My system, like Phil's, uses the same exact tweeter and midrange driver in all speakers. Timbre panning is flawless and seamless, as I'm sure Phil's is too.

    I just prefer the dipole for the side surrounds as it provides an unparalleled diffuse sound field with uncanny depth and sound effect placement. It is at once both localizable, but also seems to float in space rather than being pinpointed from an exact spot.

    For the rear, monopole all the way as you want a solid rear soundstage, like the front stage.
     
  6. wes18

    wes18 Agent

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    I've been trying to find out how to wire two rear center surrounds but to no luck. I have a Yamaha RXV1200 and it has output for one surround center speaker. People I've talked with and articles I have read make it seem that using 2 rear surrounds are the way to go. Do I only use one wire and splice it to the two or do I use 2 wires and combine into the receiver. Still learning the connection stuff.
     
  7. MichaelDDD

    MichaelDDD Supporting Actor

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    Well, I'm sure that Axiom M2i is timbre-matched to my main L/R and Center; it uses the same 5.25" driver and tweet. [​IMG]

    Now, I'm confused again....do I want just timbre-matched or do I want the SAME speakers as my surrounds? [​IMG]
     
  8. Edward J M

    Edward J M Cinematographer

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    Mark:

    You can wire them in series (doubles impedance) or parallel (halves impedance). As long as your AVR doesn't have trouble with either load, you're OK. Series is probably safer for the amp.

    Michael:

    I think the enthusiasts who use identical speakers all around are in the minority. The bipole/dipole design is unique for a reason; it provides what many consider to be optimum dispersion characteristics for side surround use.

    The same can be said for the center channel and the towers, etc. They are all optimized for their own particular application.

    It is really a matter of personal preference. For SACD and DVD-A, some prefer the monopole. FWIW, I switch my surrounds to bipole (vice dipole) for SACD and DVD-A, since the dipole setting can sound funny on certain music passages. But I always use the dipole setting for HT.
     
  9. Doug Brewster

    Doug Brewster Second Unit

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    "I think the enthusiasts who use identical speakers all around are in the minority. The bipole/dipole design is unique for a reason; it provides what many consider to be optimum dispersion characteristics for side surround use.

    The same can be said for the center channel and the towers, etc. They are all optimized for their own particular application."

    I think I hear swords being drawn, hammers being cocked, and trumpets sounding "Charge !"
    There are indeed personal preferences about this, but those who have them are all absolutely right.[​IMG]
    You'll get everything from "Timbre-matching is all that matters", to "all 7 should be identical or it will never be seamless". If you like what Phil says, go with it (no doubt it will sound great), but others will say that his use of that "timbre-matched Center" will degrade the sound quality.

    Personally, I believe that different speakers in a system have different requirements and therefore they not only don't have to be identical, but need to be different (though timbre-matched). I'm absolutely right, of course. [​IMG]
     
  10. MichaelDDD

    MichaelDDD Supporting Actor

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    Heh, Doug, I still don't know what to get.

    In the past, on the rare ocassion that I listened to 2-channel music thru Circle Surround or other DSP effect, I've thought it sounded pretty good thru my dipole surrounds. [​IMG]

    I must admit that besides a real movie theater, I've never heard a DolbyEX or DTS-ES system in person, so I can't say that I have a preference for direct or dipole rear surrounds.

    I'm leaning towards direct, out of price considerations, but I've already spent $$$ on the rest of the rig, why cheap-out now if I don't have to.

    So, the thread rolls on.

    ps
    Doug, nice to be discussing speakers again. [​IMG]
     
  11. DonnyD

    DonnyD Screenwriter

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    Mark....
    If your rear centers are 8 ohms each, run them parallel for a 4 ohm load since the Yam 1200 will run it quite well. YOU DO NOT NEED TO flip the switch (on the rear of the rec) to 4 ohm. I would run the rear centers on small..........
    As some have mentioned, two rear centers are a good way to go and it gives a little more "surround " effect according to placement. I went to 2 rear centers because of placement issues with only one and really enjoy it. I have a Yam RX-V1 and have had absolutely no problems with the load........ do a search and you'll find more info on the Yam receivers running differnt ohm loads......
     
  12. Ed O'Neill

    Ed O'Neill Second Unit

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    STOP the bus!

    First off I think Phil put up some great info...
    however it is directly copied from dolby site, he even told you that.

    I was told you should use the same as you front center or if you want "two rears" the should be the same as your front l/r. Again using the theory of timber matching. I agree that the two rears is the logical choice but remember it will only make the sound more spacious. Don't forget that the rears are mono...meaning the same sound comes out of both rear speakers at the same time.

    Having said all that here is some advice...

    Michael DDD,
    Most manufacturers speakers are timber matched and that is the most important thing. It is more important than what type of surrounds you use...mono pole, dipole, or bipole.
    I have heard various reports on what types and placement.I went with direct (mono pole), but you could always buy a speaker that is tri-pole meaning you can switch between sound formats and see which is best. I suggest you go to www.dolby.com and read and read and read.That is what I did.

    Phil,
    You should seriously upgrade your sides(surround) to be di-pole that is what is the best recomendation dolby gives!

    Mark Wessel,
    Like other people have said you can run them in series or parell in your situation.However in most situations You need to have an external amp(like me). I recently bought a 2 channel 100 watt amp which is the same impediance and wattage as my reciever and also the same brand. That is how I was instructed

    To all,
    Goto www.dolby.com you will learn a lot.Even when you thought you knew it all.

    BTW- The list of movie produced in DD ex is very small, so far..

    Terminator 2 - Judgment Day
    102 Dalmatians
    Atlantis
    Finding Nemo
    Mission to Mars
    Monsters Inc
    Signs
    Toy Story 2
    Unbreakable
    Bats
    Chicken Run
    Gladiator (2001 Oscar Winner for Best Sound)
    The Haunting
    The Legend of Bagger Vance
    The Ring
    Die Another Day: Bond 20
    James Bond: The World Is Not Enough
    The Terminator
    Spy Kids
    Austin Powers in Goldmember
    Austin Powers: The Spy Who Shagged Me Released
    Blade 2: Bloodhunt
    Lord of the Rings
    Seven
    The Astounaut's Wife
    We Were Soldiers
    Hollow Man
    Punch-Drunk Love
    The Messenger: the Joan of Arc Story
    Cast Away
    Minority Report
    Say It Isn't So
    Someone Like You
    Star Wars: Episode One
    Star Wars: Episode II- Attack Of The Clones
    The Fight Club
    X Men
    E.T. The Extra Terrestrial
    Jurassic Park 3
    The Bone Collector
    The Caveman's Valentine
    Pitch Black
    A.I.
    Harry Potter And The Chamber Of Secrets
    Harry Potter and the Sorcerer's Stone
    See Spot Run
    The Art of War
    The Exorcist-The Version You've Never Seen Released
    The Perfect Storm

    Independent Films
    RXmas
    The Dangerous Lives of Altar Boys

    Just my two cents,
    Ed
     
  13. Phil Iturralde

    Phil Iturralde Screenwriter

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  14. Ed O'Neill

    Ed O'Neill Second Unit

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    Phil,

    I am not about to start a war.

    Signed,
    ED
     
  15. Kevin C Brown

    Kevin C Brown Producer

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    I'll just put in a few cents worth.

    a) S&V has a good article in the current issue that talks about 7.1 speaker setup.

    b) I personally think that the type of rears you choose is a lot less important than the surrounds. But I also think like some of y'all, that the rears should be identical to the surrounds for the best sound field.

    c) I personally have used bipolars, omnipolars, and direct radiators for surrounds and rears. I personally prefer bipoles/omnipoles.

    I found that monopoles for me were waaaay too localizable. I had them about 12" above ear level. Surrounds about 7 ft away, and 1 ft behind the listening position. Rears form an equilateral triangle about 5 ft on a side. Now, we all probably know that the solution for me [​IMG] was to place them the recommended 2 - 3 ft above ear level. I didn't want to do that, because then, like for dipoles, you are relying on off-axis, reflected sound to get to the listener. If you've ever looked at a freq response plot, off-axis response is never that great, with the highs rolled off, and roughness in the midrange due to comb filtering between direct sound and reflected sound.

    With bipoles and omnipoles, you get direct, well imaged sound, but with reflected sound that is designed to support the direct sound waves, but which also mellow localization.

    But each person has to judge best what works in their own system, room, material, and personal preferences.

    I will say that I did prefer the direct radiators for multichannel music though. Floyd's Dark Side was sublime... But, I have exactly 3 SACDs, 1 DVD-A, and a few hundred DVDs. [​IMG]
     
  16. MichaelDDD

    MichaelDDD Supporting Actor

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    Wow, excellent posts, Phil and Kevin.

    I've had bipoles (only bipoles) as side surrounds for years now...I've had good results and like their sound.

    I've never had rear surrounds before...damn, I'm so confused! That bothers me...usually w/electronics, I examine and decide...not so easy w/this though!
     
  17. Doug Brewster

    Doug Brewster Second Unit

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    "I must admit that besides a real movie theater, I've never heard a DolbyEX or DTS-ES system in person, so I can't say that I have a preference for direct or dipole rear surrounds."

    I suggest you listen to one...but the difference would be best judged in your own home. Usually, if you're considering purchase, a decent B&M shop will let you take something home to try it out.
    In theory, the idea of dipoles as "side surrounds" makes sense to me. The idea of conventional rear surrounds also makes more sense to me than dipoles...Just thinking in terms of dispersion characteristics. Have no actual experience with this.

    "I'm leaning towards direct, out of price considerations, but I've already spent $$$ on the rest of the rig, why cheap-out now if I don't have to."

    I agree with your thinking...Meaning that if cost is the deciding factor, you would be better off spending more and getting what you want...Otherwise you're likely to be dissatisfied and end up getting them later. Of course, any decision should be based on home testing as opposed to dreams, thoughts, and theories.

    I too am pleased to be talking speakers again. In the previous thread, I was only trying to "accentuate the positive" in an arena where the negative was the only voice. Glad to be on speaking terms with you. Enough said.

    Ed O'Neill,
    "I am not about to start a war." You didn't.
    This did:
    " For the REAR surround speakers (for DD-EX/DTS-ES) are you supposed to have direct-radiating or dipoles?"
    You only got caught in the cross-fire[​IMG]
    Opinions about proper speaker configuration are a matter of personal dogma and once the question gets asked, the war begins.

    If you think Phil's response is heated, try starting a thread with either of the following:

    A) "Is there a break in period for speakers (or any other components)?
    B)Do expensive cables make much difference in the audio quality?


    [​IMG]
     
  18. Ed O'Neill

    Ed O'Neill Second Unit

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    Doug wrote,
     
  19. Kevin C Brown

    Kevin C Brown Producer

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    Here is an interesting take:

    http://www.paradigm.ca/Support/TechF...rConfusion.pdf

    Note the comment about THX-certified dipoles that are required to deliver flat freq response to the listener, but yet with a diffuse sound. I am not even sure I've *seen* a lot of THX-certified dipole speakers though. I have seen freq reponse plots of "typical" dipoles, and most of them suck. The highs are rolled off, and the midrange freqs are too rough and not smooth.

    Just looked through HT mag's '03 eqp directory, and Atlantic Tech, Jamo, M&K among others make THX certified dipoles.
     
  20. Phil Iturralde

    Phil Iturralde Screenwriter

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