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What does "out of phase" sound like?

Discussion in 'Speakers' started by Chris A H, Jul 17, 2004.

  1. Chris A H

    Chris A H Stunt Coordinator

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    I did a room family remodel and surround speaker re-wiring while my DD receiver is in the shop. Ran the wires under the carpet with some flat 16 gauge wire and afterwards did a continuity check to make sure the wires were labeled correctly.

    So I hook them up to a small stereo receiver I have and the sound is poor! It sounds like only one speaker is working, and when I get right in front of the one that seems incorrect there is very little sound and no bass. (there is no balance control on this cheap receiver BTW, but it works right in my bedroom so I do not think it is the receiver) So I then reverse the wires on one speaker, and voila the sound is full and both speakers are making what my ears tell me is a correct full spectrum sound with good balanced bass.

    So I do the continuity check again, and the results are the same, the wires are marked correctly. So why does is sound _much_ better when it appears that they are wired out of phase?
     
  2. John F. Palacio

    John F. Palacio Supporting Actor

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    How exactly do you do your continuity check?

    In a two speaker stereo setup this is what "out-of-phase" would sound like:

    There will be nothing appearing to originate in the center of the sound image. A soloist in the center, for instance, would be heard like two coming out of both the right and left speaker.

    The sound, in general, will be diffused and vague. Lastly, and assuming no subwoofer, there will be lack of bass due to cancellation effect.
     
  3. Wayne A. Pflughaupt

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    Because obviously it’s in phase, despite what the continuity check or wire markings are indicating.

    Regards,
    Wayne A. Pflughaupt
     
  4. Kenneth Harden

    Kenneth Harden Screenwriter

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    With a 2-channel system, it is PAINFUL to listen to. Try it, it will not hurt anything. I hook up systems all day long, and sometimes I get the wires wrong and they are out of phase. It is seriously painful to listen to, its like your brain is out of sync.
     
  5. Chris A H

    Chris A H Stunt Coordinator

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    Thanks for all the input.

    John - I did the continuity check with a multi-meter, so I am pretty sure of the readings.

    Jim - I did the 9V test and the woofer did not move at all, just got a small "pop" from the speakers.

    Wayne - yea, I have always been a guy to "trust my ears" when it comes to this stuff. I was just fishing for any more ideas as to why it doesn't add up. I will in the end go with what sounds the best no matter what the readings say. But if they do match up then so much the better.

    Kenneth - I wouldn't call it painful, but is sure is not something I would choose to listen to at all. It just sounds incomplete and out of balance, like it isn't even stereo.

    Thanks again.

    Chris
     
  6. Lewis Besze

    Lewis Besze Producer

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    It certainly should,however it isn't a continious movement.It stays either out or in[phase] and exhibits a faint humming sound.Once the battery removed the woofer returns to it's resting point.
     
  7. John F. Palacio

    John F. Palacio Supporting Actor

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    Hi, Chris.

    What I meant is, being the ends of the cables are far apart, how did you physically get the VOM leads to check continuity?

    Did you do this before the wires were run?
     
  8. Chris A H

    Chris A H Stunt Coordinator

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    John - I connected another length of wire to the receiver end of the surround wire(s) and ran it to the speakers. I then stood on a ladder and did the tests, being very careful to isolate the wires.
     
  9. Jeremy Anderson

    Jeremy Anderson Screenwriter

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    Room acoustics, reflections, etc. can cause phase reversal, regardless of whether the speaker is wired correctly. An easy way to test for this is to listen to something with vocals centered, swap the leads to one speaker and listen again. You'll know it when the vocals snap into place.

    This is also an issue in multi-channel, where you not only have to deal with speaker phase but with delay times as well (so that sound from all speakers arrives at the listening position simultaneously). Having the speaker delay 1ms off can cause it to sound out-of-phase. In this case, it helps to have tones centered in-between speakers or have phase tests. Avia has phase tests for 5.1 (as does the THX Optimode on a lot of DVD's), and DVE has tones centered between each channel in 6.1 going around the room that really help nail phase and delay.
     

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