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How do i know if the phase of my sub is correct?

Discussion in 'Archived Threads 2001-2004' started by Mike Dr, Apr 4, 2002.

  1. Mike Dr

    Mike Dr Stunt Coordinator

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    OK, as those of you who've seen my more recent posts know, I just completed my tempest sonotube with MCM amp .. now I left the phase to the middle where the little dot is .. when I turn it to 0 or to 180 or to any other value I really can't tell the difference... I have the Avia dvd , but there's only that one lfe sweep tone to test/tune it .. how can I figure out what phase I need to set (if any)

    thanks
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    You need to play a tone or narrow band noise at a frequency close to the crossover so that about equal SPL is comming from the sub and sats. The choose the loudest setting near the listening area. When the sub plays alone, the phase has no effect on the output.
     
  3. Mike Dr

    Mike Dr Stunt Coordinator

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    Hmm.. I dont know if I understand exactly.. another thing is that my receiver is hooked up for dvd-direct and unless there's a distinct LFE signal coming, the subwoofer does nothing.. and as far as i know, AVIA doesnt have a single tone that does speakers and sub at the same time... any other suggestions?
     
  4. Pete Mazz

    Pete Mazz Supporting Actor

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    Avia won't send anything to your sub if your player is hooked up with analog bypass. Hook it up with the digital connection if you can and set it up that way.

    How do you reproduce the audio from movies with that setup???

    Pete
     
  5. Rick Guynn

    Rick Guynn Second Unit

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    Mike, you need to check and see if your speakers are set to 'small' if they are set to large, the only bass that will go to the sub is the LFE. To help with the phase setting explanation..
    Once you get your speaker set up properly on your receiver, find out out what the Xover frequency is for your receiver (or sub if you aren't using the receiver Xover). Then get ahold of a test tone at or very near that frequency. If you have a computer you can hook up to your receiver, you can use a tome-generator from your computer (or use it to burn one to a CD)then play it through your speakers. When the waves from the mains and sub are in phase is when the sound will be at its loudest. Adjust the phase on your sub until the sound hits is at its loudest.
    I am actually getting ready to experiment with using a mic (probably my SPL meter) and an Oscope (maybe windows based one) to see if I can 'see' the waves and set the phase by looking at thte scope display [​IMG]
     
  6. Mike Dr

    Mike Dr Stunt Coordinator

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    OK . there seem to be misunderstandings... so here's my exact setup:

    Dvd player IS hooked up with a digital connection (coax)

    Receiver (Marantz SR7000) is set as follow:

    Xover (fixed) at 100hz

    all speakers ARE set to small

    the bass management is weird when in DVD-DIRECT

    I think I should try one of the other modes, but I was under the assumption that to get un-altered signal, you should be in DVD-DIRECT.

    Regardless, when in dvd-direct, the receiver does not pass any signal except LFE to the sub. (and this works just fine in movies since there's plenty of LFE signal on most dvd's)

    So basically, the only way for me to test phase is to set the receiver to one of the non-direct modes and then play a tone.
     
  7. Rick Guynn

    Rick Guynn Second Unit

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    I don't know anything about Marantz setups, but on my Yamaha I have the option of telling the bass to go to the sub, mains, or both. Even if I had all of my speakers set to small (including the mains), if I had bass-out set to mains, it would send it to the mains. You might check to see if this is the situation on yours.

    Otherwise, I can't imagine why you would not be getting bass from your sub on something besides the LFE.
     
  8. Pat

    Pat Agent

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