Adjusting Subwoofer Phase

schwarcw
schwarcw Posts: 7,339
edited March 2006 in Basic Hookup/Wiring Questions
Anyone have any tips or could suggest a good sound track for testing and adjusting the phase angle for a subwoofer. I've had my SVS PB-12/ISD for about five months. I tried listening to the affect of changing the phase with the knob on the back of the unit. I really couldn't hear amy difference in the sound by changing the phase in 20 degree or so increments. The SVS manual states that his is the hardest adjustment to make and in many instances the user may hear no affect.

I was wondering about some of your experiences or suggestions that may help. I haven't tried the SPU meter, and I don't know if this instrument would be effective.

Your suggestions and advice are welcome. I doubt that I'm the only one curious about this.
Carl

Post edited by schwarcw on
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  • fgr41
    fgr41 Posts: 432
    edited March 2006
    /me perks up and waits for a responce.
    Front
    Polk RT800i (BI-wired)
    Rear
    Polk RT600i
    Center
    Polk CS400i (BI-wired)
    Sub
    SVS 25-31PCi (22Hz tuning port)... it's SubHuman
    Receiver
    YAMAHA RX-V1400
    TV
    Mitsubishi WT-46807 HDTV
    HD receiver
    T i V o HR10-250
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  • MattN03
    MattN03 Posts: 558
    edited March 2006
    I'd be interesting in hearing more info on this too.
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  • unc2701
    unc2701 Posts: 3,587
    edited March 2006
    It'll depend on where you've got it crossed over and how low the mains go. It's usually used to correct a problem with phase cancellation between the mains and the sub since some amps invert phase.

    The easiest approach is to use tone generator software- run a tone at the crossover freq through your system, then have someone twist the knob (or flip the switch if you've got 0/180) when you're in the listening position. listen for the bass to get a little louder. It can be hard to pick out what's just right. It's easy to tell when it's out of phase- just sway a little side to side and you get this weird shifting effect. Some rooms don't display this effect at all, in which case phase doesn't matter.
    Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
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  • schwarcw
    schwarcw Posts: 7,339
    edited March 2006
    unc2701 wrote:
    It'll depend on where you've got it crossed over and how low the mains go. It's usually used to correct a problem with phase cancellation between the mains and the sub since some amps invert phase.

    The easiest approach is to use tone generator software- run a tone at the crossover freq through your system, then have someone twist the knob (or flip the switch if you've got 0/180) when you're in the listening position. listen for the bass to get a little louder. It can be hard to pick out what's just right. It's easy to tell when it's out of phase- just sway a little side to side and you get this weird shifting effect. Some rooms don't display this effect at all, in which case phase doesn't matter.

    I'm assuming that I should do this with all channels driven at this frequency (20 - 80 Hz) to find any standing waves?

    Carl
    Carl

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