Crossover Question

Discussion in 'DIY Discussion' started by murray johnson, Aug 23, 2006.

  1. murray johnson

    murray johnson

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    Can someone tell me whether this is just a parallel 2nd order crossover or something different?
    When I try to redraw it in a conventional way it doesn't layout the same. Any ideas what kind it is & how & why it might be different?

    [​IMG]
     
    Last edited by a moderator: Aug 23, 2006
    murray johnson, Aug 23, 2006
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  2. murray johnson

    Ant

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    Odd isn't it.

    Mark earth on it and flip the LF inductor to the right side and it should make more sense. And put the parallel C and L after the series ones.

    Arrgghh thats done my head in, must go and solder something :)
     
    Ant, Aug 23, 2006
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  3. murray johnson

    Ant

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    Well it works :D

    [​IMG]
     
    Ant, Aug 23, 2006
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  4. murray johnson

    murray johnson

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    Hi Ant,

    This is the layout of the Vitavox crossover in my speakers. I've been looking at the diagram I made trying to work out how it works and if it really is just a straight 12 dB/octave 2nd order job.

    The design probably dates from the 50's/60's but I don't think mine were made that long ago as the caps are some kind of film polyprop type and the older ones would have been PIO. Coils are both aircore though.

    I'm glad it seems to work. It certainly sounds as though it does, I just can't get my head around the way its laid out.
     
    murray johnson, Aug 23, 2006
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  5. murray johnson

    Ant

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    I've used too brain cells on it :) it's beyond my meager skills to be honest.

    It did crap out at the crossover point but then again look at the scopes, they were sine waves on the way in :)

    I set the crossover point at 100hz I think (if it behaves like a regular 2nd order) and the scope on the left is showing 199hz not 99
     
    Ant, Aug 23, 2006
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  6. murray johnson

    mosfet

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    Series crossover?
     
    mosfet, Aug 23, 2006
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  7. murray johnson

    Ant

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    Well it is but the zobel is across the entire signal, but has that one wire between the drivers.

    odd ball
     
    Ant, Aug 23, 2006
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  8. murray johnson

    mosfet

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    I changed my first dumb-ass thought Ant!
     
    mosfet, Aug 23, 2006
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  9. murray johnson

    Ant

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    I've got it I think, It is a normal second order with the phase reversed on one of the drivers.

    I wasn't calling you an odd ball referring to the design :)
     
    Ant, Aug 23, 2006
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  10. murray johnson

    Ant

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    [​IMG]
    plus
    [​IMG]
     
    Ant, Aug 23, 2006
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  11. murray johnson

    Tenson Moderator

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    Guys Mosfet is right it is simply a 2nd order series crossover.
     
    Tenson, Aug 23, 2006
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  12. murray johnson

    Ant

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    but the connection between the two drivers wouldn't be there would it?
     
    Ant, Aug 23, 2006
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  13. murray johnson

    mosfet

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    Yep, I know Ant. I was referring to my own engaging keyboard before brain post!

    (not a first order with zobel, 2nd order series as T says)
     
    mosfet, Aug 23, 2006
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  14. murray johnson

    Tenson Moderator

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    Oh I see what you mean. It is the same as a 2nd order series but the woofer's inductor is in the negative line instead of the positive. I'm not sure how that would play out, it is a bit of a tease. Ask on www.diyaudio.com
     
    Tenson, Aug 23, 2006
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  15. murray johnson

    Ant

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    Looks familiar :) D'Appolito

    [​IMG]
     
    Ant, Aug 24, 2006
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  16. murray johnson

    Ant

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    Actually 2nd order pseudo D'Appolito, take out R2 and the second driver and you have Murray's crossover.

    Actually Murray is it a two way it's used in?
     
    Ant, Aug 24, 2006
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  17. murray johnson

    murray johnson

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    It is the xover between the bass horn & midhorn and happens at about 500 Hz. Being an old 'pro' unit, the inputs are labelled 1 & 2 rather than + & - and the o/ps to the drivers are each also labelled 1 & 2 as are the drivers themselves.

    It sounds ok.

    What are the pro's & cons of series type xovers (if that is what it is) compared with parallel type?


    That D'appollito xover is the same. Mine also has the L Pad on the high pass side but I left it out for simplicity's sake
     
    murray johnson, Aug 24, 2006
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  18. murray johnson

    murray johnson

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    murray johnson, Aug 24, 2006
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  19. murray johnson

    Ant

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