Phase shift

Discussion in 'Home Theater Projects' started by David Giesbrecht, Jun 8, 2003.

  1. David Giesbrecht

    David Giesbrecht Second Unit

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    how come I keep hearing about 2nd order crossovers having a phase shift? do they actually reverse the phase of the speakers in the network?
     
  2. RichardHOS

    RichardHOS Second Unit

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    Yep.
     
  3. Patrick Sun

    Patrick Sun Moderator
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    Theoretically/simplistically speaking, each "order" of a crossover filter introduces a 90 degree phase shift at the crossover point. So with a 2nd order crossover network, you've got an 180 degrees phase shift that gets corrected by flipping the polarity of one of the drivers (for a 2-way), otherwise, you'd experience a null at the crossover point.
     
  4. David Giesbrecht

    David Giesbrecht Second Unit

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    Does a first order network put a 90 degree phase flip on the driver? I heard that first order networks didn't effect phase and that was one of their advantages.
     
  5. RichardHOS

    RichardHOS Second Unit

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    I was going to ask the same thing. [​IMG]

    I know I've read it before, but now I have myself thoroughly confused.

    a 24dB/oct has a 360 degree phase shift. A 12 dB/oct has a 180 degree phase shift. That would seem to suggest 6dB/oct = 90 deg and 18dB/oct = 270 deg. But I was almost certain that a 6dB/oct filter didn't have a phase shift.

    Someone (hopefully someone smarter than I) please help! [​IMG]
     
  6. Hailan R

    Hailan R Agent

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    mmmmm good question, im also wondering is there a way to correct this on 3rd order....
     
  7. Patrick Sun

    Patrick Sun Moderator
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