Recommended wiring for bipole surrounds on rear wall?

Discussion in 'Archived Threads 2001-2004' started by Trenton McNeil, Mar 6, 2001.

  1. Trenton McNeil

    Trenton McNeil Second Unit

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    I have Boston Acoustics VRS Pro surrounds, and nowhere to mount them but on the BACK wall (well, I have the left rear wall available, but think it would be better to stay symmetrical...).
    kinda like this:
    |
    |
    |
    |
    |
    |
    |
    |___^______^____|
    where the ^ represents the speaker driver on the back wall.
    I have heard that it is necessary to reverse polarity on one of the two channels to get proper response, is this correct? Will I find other problems with a setup such as this? The --> right hand side of the room opens into a dining room, that is why there is no wall to mount the speaker on the side.
    Additionally, there is a vaulted ceiling that slopes down toward the back wall, and I have toyed with mounting the speakers there, but not sure that would be such a good idea, aesthetically OR acoustically.
    2nd question: how far apart should the speakers be from each other assuming they are about 4 feet behind the seating position?
    Thanks, I am dying without my rear channels hooked up and want to get it right the first time!
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    [​IMG]
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  2. Trenton McNeil

    Trenton McNeil Second Unit

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    CORRECTION: These are DIPOLAR surround speakers. Sorry for the confusion.
     
  3. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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  4. Trenton McNeil

    Trenton McNeil Second Unit

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    99% sure. It doesn't say so on Boston's site, but their recommended mounting procedures point towards them being dipolar and creating the diffuse soundfield such as dipoles are supposed to do.
    The problem I envision with wiring them out of phase is that the tweeters now become 'in-phase' with each other, but the single bass unit will be out of phase.
    How messed up is that?! [​IMG]
    I think I'm going to hang them on the sloped ceiling on a perpendicular plane to the seating position, and possibly add a 2nd pair of monopole speakers on the back wall if the effect is lost.
    How did you make it back? Did you catch the 10am?
    ------------------
    [​IMG]
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  5. Patrick Sun

    Patrick Sun Moderator
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    Gregg, sorry I didn't get your call until late Monday night. You're going to have to give us Atlantans more lead time...
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  6. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    Trenton, pretty sure they are bipoles, meaning bi directional. Chris White has the same ones, maybe he will chime in.
    The 10 am flight was cancelled, so I ended up taking the train to some mall for a few hours. I ended up flying into Boston (at 1030 PM) and then renting a car to drive home. I made it back this morning at around 430 am.
    Gregg
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  7. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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  8. Trenton McNeil

    Trenton McNeil Second Unit

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    So you see my quandary in mounting them on the back wall and wiring out of phase. I'll mess up the midrange frequencies since the midrange drivers will be out of phase, and cancel each other out.
    I am thinking that the ceiling on a perpendicular plane to the seating location is going to be best:
    http://www.bostonacoustics.com/manuals/VRSPlacement.pdf
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  9. Robert A

    Robert A Stunt Coordinator

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    I'm pretty sure that the speakers you have are dipole. If that is the case don't reverse the polarity. I don't know if you'll like them without the wall on the right. They are meant to be used mounted on the walls directly to the side of the listening area. The positive polarity sides should face forward and the negative back. Monting them on the cieling will be better but not as good as mounting them on the walls. If you mount them on the back wall it will defeate the purpose of the dipoles and ruin the effect. There should have been some documentation on how to place these babies included with the rest of the stuff. It looks like there is a little bit of wall at the very back of the room. If nothing else try mounting them on the walls far enough back to get on that wall.
    Time to build that killer theater in the garage and start parking outside.
     

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