How can I tell if speakers are In-Phase or Out of Phase?

Discussion in 'Archived Threads 2001-2004' started by David Ruiz, Aug 18, 2001.

  1. David Ruiz

    David Ruiz Second Unit

    Aug 13, 2001
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    I have a problem. I was running the THX optimode, and it talks about in-phase and out of phase. Now, when it plays the very first test L/R, you can tell, when either of them are in phase or out of phase. Now here is the problem. The mains are DIFFERENT brand than all of the other ones:
    L/R "Sharp"
    C/RL/RR "Philips"
    When it starts playing the other test, I can't figure out which ones are in phase or out of phase...they sound almost exactly the same? I have them connected by Red on Red and Black on Black, but they sound EXACTLY the same in-phase or out of phase, so how can I tell? By the way, NONE of the speakers have the same TONE. They are all of TONE even though 3 of them are all the SAME EXACT PHILIPS speakers! Each tone sounds completely different from one speaker to the other.
  2. Todd Hochard

    Todd Hochard Cinematographer

    Jan 24, 1999
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    I have not played with the THX Optimode stuff, but I have used a Test on AVIA to check phase.
    Generally speaking, if I send the same signal in-phase to two speakers, I should be able to pinpoint the sound between those two speakers. When the signal goes out-of-phase, the sound should move "into the room," and no longer be able to be localized.
    If the sound seems out-of-phase all the time, you likely have some time-delay/speaker placement issues. Experiment with speaker placement (two inches closer/farther from you can make the difference), to fine tune this. Mess with toe-in, too. It can get time consuming, but worth the effort.
    Once you get this in, you will experience surround sound like never before. Trust me. [​IMG]
  3. Chris PC

    Chris PC Producer

    May 12, 2001
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    Out of phase speakers are a funky sounding deal. Usually its easy to detect. If you have them wired 100% correct and you are 100% sure, then don't worry. The test I believe is so you don't have to double check and crawl behind your system to see.
    Usually in phase speakers have a stable image. Out of phase speakers not only sound like the sound is all around the room, but almost inside your head in a weird way too.
    One way to test is to take your 2 surround speakers and place them facing one another, perhaps an inch or to away from each other. Play the test tone or some bass. You should notice a lack of bass when wired out of phase.
    Good luck.
    [Edited last by Chris PC on August 18, 2001 at 09:46 AM]

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