Center channel Right channel phase problem

Discussion in 'Archived Threads 2001-2004' started by John H, Sep 11, 2001.

  1. John H

    John H Second Unit

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    I am having trouble with center channel right main channel phase.
    I use Def Tech BP2000TL bipolar mains and a C/L/R 3000 monopolar center on top of my RPTV with a 1½" front overhang.
    I am using the VE center channel polarity test.
    The voice and test tone are centered between the Left and Center channel.
    The test for the right main and center speakers is not firmly centered between the two.
    I have switched speaker leads at the amplifier left main for right main and the problem still lies with the center and right main speakers.
    I have each main channel precisely positioned with measurements and use a laser tool for aiming.
    I use 2 component cabinets on each side of my monitor. The left cabinet is the same height as the monitor. The one on the right extends 3" above the monitors top. Could this be the problem?
    John
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    Bedroom Based Theater
    Looking through a glass onion
     
  2. Jim A. Banville

    Jim A. Banville Supporting Actor

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    You may want to check the polarity of the drivers themselves to see if they were connected correctly at the factory. You can use a 9 volt battery attached to the the main speaker connection on the speaker (binding posts). With the positive point of the battery on the "+" binding post and the negative point on the "-" binding post, all the drivers should move out into their full extended position and stay there. If any of the drivers pull in, it is wired backwards.
     
  3. Patrick Sun

    Patrick Sun Moderator
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    I would swap the left and right speakers and listen for the same problem to occur with the "new" right speaker. If it's not there, but the "new" left speaker is "out of phase" with the center, then try Jim's suggestion. But if you get the same response, then you need to balance out the heights of the left/right speakers.
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  4. Bob_A

    Bob_A Supporting Actor

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    It seems like the extra height may be affecting things. How much offcentered is the sound? Are you getting the same output from your left and right mains?
    [Edited last by Bob_A on September 12, 2001 at 11:45 AM]
     
  5. John H

    John H Second Unit

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    I used original BP2000's and BP30's before the BP2000TL's and experienced the same effects.
    The test tone image is somewhat centered between the right main and center speakers, it is just not firmly centered. You can still tell the tone is being generated from the R/M amd C speakers.
    With the left side it is only perceived as a firmly centered tone.
    Yes, the R/L output has been calibrated with a SPL meter to the same level. Their adjustment values only vary by 1dB in my pre/pro speaker setup.
    John
    [Edited last by John H on September 12, 2001 at 12:07 PM]
     

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