Whats going on??? Why can I localize my sub?????

Discussion in 'Archived Threads 2001-2004' started by Jon Taylor, Oct 26, 2001.

  1. Jon Taylor

    Jon Taylor Auditioning

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    Hi,
    Why oh why can I localize my sub?????
    Its in a corner, the front right of my room, about 14" from the front wall and 7" from the right wall.
    When listening to stereo its fine, no problems, blends in perfectly. Just when I use any surround mode it sounds like most of the 'weight' of the sound is coming from the right hand side, and I can localize the sub.
    Please help!!!
    Jon
    [​IMG]
     
  2. Guy Kuo

    Guy Kuo Supporting Actor

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    I'll go way out on a limb and take two guesses
    Scenario A - Your processor has an unusually high crossover frequency or no crossover and this is spilling high bass (localizable) to the sub.
    Scenario B - (I think more likely but a bit more insidious)
    In stereo mode the material is primarily music and doesn't have as deep bass extension so the boom and localizability effect you note in surround isn't as apparent.
    When the subwoofer and mains are both playing signals in their overlap frequency range you are getting phase cancellation in the mid bass but reinforcement of upper bass and this exaggerated upper bass is causing the localizable effect of the subwoofer.
    Would be worth having an assistant vary the subwoofer phase while you listen. That may solve the problem.
    Just two guesses. I'm sure there will be others.
    BTW I assume you have set the subwoofer and speaker distances/delays correctly in the receiver already.
    ------------------
    Guy Kuo
    www.ovationsw.com
    Ovation Software, the Home of AVIA DVD
    [Edited last by Guy Kuo on October 26, 2001 at 04:08 AM]
     
  3. Jon Taylor

    Jon Taylor Auditioning

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    Guy,
    It can't be the reciever crossover as it is a Denon 3801.
    Phase cancellation sounds like a good possibility. I will try that tonight.
    Thanks for the reply
    Jon
     
  4. Guy Kuo

    Guy Kuo Supporting Actor

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    Oh one other scenario.
    The room is small enough (say 12 L x 12 W feet) that one or more of the mode reinforcement frequency peaks is in the high bass range. That would cause the sub to create enough high bass to become localizable. Hopefully, this isn't the case.
    ------------------
    Guy Kuo
    www.ovationsw.com
    Ovation Software, the Home of AVIA DVD
     
  5. John Morton

    John Morton Stunt Coordinator

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    I had the same problem. I thought my system sounded good until I put an inner tube under my receiver and CD player (dis-believers = go ahead and laugh!!). I could never tell before this change because of the distortion and re-amplification of the feedback bass. As it turned out, my sub was 180 out of phase from the mains.
    My sub also seems to blend better since I turned the sub's cross over freq knob up all the way to 150 hz. At the same time, I had to lower the volume by a full notch (out of 10). My only thoughts on this was because I wasn't hearing the correct level of the total bass spectrum, so my mind was telling me to raise the sub's volume to compensate for what I was missing?
    My system sounds better than ever now!! Thanks again to all the HTFers out there!!
    ------------------
     
  6. Norm Strong

    Norm Strong Stunt Coordinator

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    You can localize your sub because that's where you put it. You don't even have to listen to your system, and you can tell right where it is.
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    Norm Strong ([email protected])
     
  7. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    Also be sure the calibration levels are OK. I believe denon supports individual bass levels per sound *mode*. So it's possible you're OK for the 2 channel mode,but not for the surround modes.
    There will also be an issue of source material. Some bass heavy LFE encoded sources will simply push more bass through the sub.
    Which sub it is? I'm wondering if it could be throwing off a lot of high freq harmonics if the LFE pushes it too hard?
    TV
     
  8. Peter Johnson

    Peter Johnson Stunt Coordinator

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    Whats the xover slope?
     
  9. Jon Taylor

    Jon Taylor Auditioning

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    The sub is a KEF PSW2000 it come with the KHT2005 package (the eggs).
    I have no idea about the xover slope.
    The sub level is the only one I am unsure about as I was unable to set it while I borrowed the shop's SPL meter. If it is even a little too loud will this lead to localization?
    Also my room is L-shaped and the sub is in the corner of the L if you get what I mean. Could this be the problem?
     

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