THX Optimizer (Need Help)

Discussion in 'Speakers' started by Antonio_B, Oct 13, 2004.

  1. Antonio_B

    Antonio_B Stunt Coordinator

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    I recently purchased my first home theatre;hooking all the equipments was quite simple but the hard part is to hook up the speakers in the right way.

    The first test in the "THX Optimizer" is a "Test Tone" and all my speakers seems to answer back.

    But the problem is with the second test which talks about "In-Phase" and "Out-Of-Phase".
    It tells me that i should reverse the wires on all my speakers because i'm not "In-Phase" and that's exactly what i did: (+) to (+) and (-) to (-)
    And i still get the same answer: "Out-Of-Phase".


    Can someone help me? I've been trying for 3 days now.It's killing me [​IMG]

    Thanks, [​IMG]
     
  2. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    In most cases the phase test should just be a double-check to make sure you didn't goof up a connection. This is especially true with most modern receivers that allow you to adjust the signal delay to individual speakers by entering the distance to the listening position. But there still may be some circumstances, I guess, where the phase problem needs to be solved by reversing wire polarity.

    In your case I would first manually check that I had connected all speakers with a consistent polarity. Then I would check my receiver's distance settings for accuracy. Then if you're happy with the results (that is, while you listening to music/movies) then don't worry about what the phase test is telling you. Every time I've tried it (admittedly only a couple of times) it has been difficult to distinguish which setting sounded "right" since I didn't have a reference for what their test tone is supposed to sound like.

    Lastly, this caught my eye
    "It tells me that i should reverse the wires on all my speakers because i'm not "In-Phase" and that's exactly what i did"
    The reason to reverse wires on one speaker is because it is out-of-phase with respect to the rest of the system. If you have a real phase problem with one speaker and try to solve it by reversing the wiring on ALL of them then you'll still have a phase problem in the end.
     
  3. Antonio_B

    Antonio_B Stunt Coordinator

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    Ryan,

    The thing is that i tried so many combinations and it still doesn't work.

    All my speakers are marked with a red box except for the right speaker in the front.
    And the thing that caught my attention is that all the speakers are connected to the receiver in the same way.

    But i can notice the difference between "Out-Of-Phase" and "In-Phase".
    When the test displays "In-Phase",I feel it's "Out-Of-Phase" on my system,and vice-versa.

    So the test is probably right...
    I have no idea what to do.
     
  4. JohnSmith

    JohnSmith Supporting Actor

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    I think you're getting confused. Leave all speakers wired corretly. Now output the various in-phase and out of phase tests. For example left in phase right in phase- the sound should be equal in sound. When the left in phase, right out of phase is outputted it kinda feels weird, like your right ear is closed, and the right speaker noise should be harder to hear.

    If something is wrong with internal phasing of the amp or speaker with left in phase, centre in phase, right in phase test (but the right sounds "weird" then check that one speaker)
     
  5. Antonio_B

    Antonio_B Stunt Coordinator

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    Everytime i run the test i notice that it's always the opposite that happens.

    For exemple when the test tells me that it's displaying an "In-Phase" test,i feel it's an "Out-Of-Phase" test.

    And when it says "Out-Of-Phase",it sounds to my ears like an "In-Phase".

    And reversing the wires doesn't solve the problem either.
    Oh by the way,all my speaker wires are different(not the same length)if that would alter the results.
     
  6. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Wire length should not cause a problem for lengths of less than a mile or so since electrons travel at near the speed of light.

    My suggestions:

    1) Verify that you have a problem when listening to music and/or movies. If not, then what are you going nuts about? You bought this for the music/movies, right? Not the test tones. I'm not sure what disk you're using but it could just be a hosed up calibration tone. It would certainly NOT be the first time.

    2) Verify that you are NOT using bipole or dipole speakers. I could see this hosing up a phase test.

    3) Verify that all of your speaker drivers are working properly. A blown driver could manifest itself in strange ways during a phase test.

    4) Verify that your receiver's distance settings are correct. There's no sense in even trying to match phase until you've got this setting correct since it introduces delays into the system and phase differences are all about delaying one signal with respect to another.

    5)Your results seem to indicate that the right front speaker may be out of phase:
    "All my speakers are marked with a red box except for the right speaker in the front."
    It doesn't really matter if your cones move forward first or backwards first ... just as long as they all move in the SAME direction. But remember that this includes the subwoofer - you want it in phase also.

    6)If all this still fails, consider coming back to the front side of the mirror, Alice, where the laws of physics hold true[​IMG]
     
  7. Ian-Fl

    Ian-Fl Second Unit

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    In and out of phase has to do with the possition of the speaker cone. If there's a positive voltage the speaker cone is forward. When speakers are out of phase the cones are not moving together but opposite hense the out of focus sound.
    http://www.thx.com/mod/techlib/phase.html
     
  8. Antonio_B

    Antonio_B Stunt Coordinator

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    The reason i'm going nuts about this,is that i feel like i'm loosing a lot of the audio experience.

    When it's "Out-Of-Phase" i feel much more absorbed in the ambiance.
    When it's "In-Phase" there's no "audio-absorbtion".
    Of course it's supposed to be the opposite.

    Oh by the way,Ryan you said that distance/delays settings on your receiver will give you the same results compared to the Out-Of-Phase/In-Phase test?


    Ian,when you were talking about cones,does it relate to distance/delays settings?

    Thanks,
     
  9. ChrisWiggles

    ChrisWiggles Producer

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    What?

    I'm confused by your terminology, and if you don't know what you're listening for, then you may have things right( it sounds like it).

    Using just your front speakers: they should be arranged in some kind of equilateral or isosceles triangle. They will be equal distance from your listeing position, pointed symmetrically, etc. With you in the listening position in such a setup, everything should be phased right with no time delay issues, etc, if things are hooked up right.

    Then you play a test tone with these two speakers, such as the in and out of phase tests on Avia, the in-phase test will be a very distinct sound coming from the front, and should image the noise between the speakers, centered, with minimal ambiance.

    When out-of phase, the imaging will deteriorate or be gone completely, and things will sound very ambient and lose focus.

    If you spend some time with stereo music material in such a situation, you can hear the effects if you reverse the polarity on one of your speakers, imaging will do very strange things, things may sound like from the sides/behind, it's very unnatural.

    If you've experienced this in the past, you know what I mean, but sometimes it's difficult to describe the experience of hearing things out of phase to someone who may not know what yo listen for. Using the test tones, you should hear a difference if you pay attention, and you do NOT want the strange ambience and everything, ad that indicates wrong phase.
     
  10. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    "The reason i'm going nuts about this,is that i feel like i'm loosing a lot of the audio experience.

    When it's "Out-Of-Phase" i feel much more absorbed in the ambiance."

    In the end, its your ears and enjoyment that count when it comes to home theater. Its not worth being right if it sucks all the joy out of it.

    "Oh by the way,Ryan you said that distance/delays settings on your receiver will give you the same results compared to the Out-Of-Phase/In-Phase test?"

    Not necessarily the SAME results. But it will affect phase to some degree (Ha! I made a funny!). It just makes sense to make this correct before you try to check phase.
     
  11. Antonio_B

    Antonio_B Stunt Coordinator

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    LMAO Ryan,i adjusted the phase settings and it sounds a bit better now but still not the answer i got from
    "Out-Of-Phase".

    Yeah you almost got me...[​IMG]
     
  12. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Well, I hope you get it figured out in the end. Maybe try a different calibration disc? I dunno, but by now you've earned yourself a movie break.
     

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