need help with DIY speaker crossover

Discussion in 'Archived Threads 2001-2004' started by Ryan T, Jan 30, 2002.

  1. Ryan T

    Ryan T Second Unit

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    Hi,
    I'm going to try and build a Center channel speaker and I have a few questions. First the drivers I want to use are
    1x Morel MDT-29 1-1/8" soft dome tweeter
    2x Dayton 5-1/4" midbass
    i'm trying to fiqure out how to design design a crossover for this speaker but i'm completely lost[​IMG]. I'm looking into a pre-made crossover but I don't think it's wise to use one of these...
    http://www.partsexpress.com/pe/showd...=5620&CATID=48
    Is there any easy way to make a crossover or should I just buy the pre-made one?
    Ryan
     
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Try the Madisound board. They will need to know the enclosure volume and port info or if its sealed.
     
  3. Ryan T

    Ryan T Second Unit

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    Brian

    where is the Madisound board at?

    Also I looked into the drivers some and I think I'm going to spend a bit more and get the Dayton 6 1/2" and the Morel MDT-30. The dimensions that I want for my box are W 22.5", H 9.5", D 13.5" and it will be sealed. If I do go with the pre-made crossover what type of sound should I expect? I'm trying to build a center speaker that sounds as good as my Paradigm Titans or better. Thanks.

    Ryan
     
  4. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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  5. Patrick Sun

    Patrick Sun Studio Mogul

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    Also, if you pick drivers that Madisound sells, you can have them whip up a LEAP crossover for you (I think the service cost around $60, but it might be worth it if you have no access to measuring gear and crossover optimization modelling software).
     
  6. Ryan T

    Ryan T Second Unit

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    Thanks for the help. I think for now I might just go with the Dayton crossovers for the sake of simplicity. I was just looking through a Radio Shack book (Advanced speaker designs)

    and it has formulas for making crossovers. I might try the madisound board in about a month or so. I'm spending all my money buying a Tempest and all the MDF and these drivers for my speakers so I don't think that I can pay them to design me a crossover just yet. According to my book the crossover point is called Fc so, I noticed that Dayton sells there pre-made crossovers with different Fc points. They are at 2,000Hz, 2,500Hz and 3,000Hz. Does anyone know what Fc point I should get? Looking at the specs from my woofers and tweeter, I think I might try to get the 2,500Hz crossover. Unfortunately it's not instock right now so I might have to go with the 2,000Hz one. I'm a little worried that 2,000Hz might be to low because the tweeter starts to drop off at 1,800Hz would this be a problem? Again thanks for the help.

    Ryan
     
  7. Robert_J

    Robert_J Lead Actor

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  8. Ryan T

    Ryan T Second Unit

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    Robert

    I did see this design but I never really though about useing it. I was just looking at the tweeter and they say it has been compared to the morel with supprising results, I will give this design some serious thought. When do you think you will be finished with the speakers? When you do get them done could you tell me what they sound like?

    Ryan

    P.S. do you think the Dayton III would sound better then my Paradigm Titans?
     
  9. Ron Shaw

    Ron Shaw Stunt Coordinator

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  10. Robert_J

    Robert_J Lead Actor

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    Ryan,
    It will be at least a month before I can finish my DIII's. I have to finish a pair of DII's, a DIII as center channel, a 12" DVC sub in a 1.2ft^3 sealed box and install some Dayton 6.5" speakers in the ceiling all for a family member first.
    Until then go to the Parts Express Tech Talk board and search for reviews.
     
  11. Jonathan DA

    Jonathan DA Screenwriter

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    Ryan,
    I would caution against trying to design your own crossover if this is your first full range speaker project. Using a prebuilt crossover or text-book formulas to calculate your component values will not yield good results. A crossover has to be individually designed for each driver/cabinet combo to take into account things such as the natural roll off characteristics of the drivers, break-up modes, edge diffraction, baffle step, polar response, phase, sensitivity differences, frequency response irregularities, comb filtering (especially in a sidways MTM like your proposed center channel) etc. Without access to measurement software like Luad or Clio, and modelling software such as LspCAD Pro or Calsod, you are going to be in for a rough time. Heck, I have access to all that and it is still tough to get a good design sometimes.
    A better bet would be to build a kit that already has a custom crossover design included. Madisound, PartsExpress, Zalytron, Dillon Acoustics, BESL, etc. All offer good kits in all price ranges.
    Don't want to kill you enthusiasm, but a good kit crossover is better than a poor shot in the dark. You'll be happier in the long run.
    Jonathan
     
  12. Ryan T

    Ryan T Second Unit

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    Jonathan
    If I build DIY speakers I will use the Dayton III design on the Partsexpress web page. It has all the crossover parts listed, so all I have to do is solder the parts together. What I mean buy "if I build DIY spekers" is explianed here....
    http://www.hometheaterforum.com/htfo...threadid=43404
    Unfortunately all the money I was going to use on a tempest and DIY mains and center where used up on receiver. so I have to set back my tempest project for about another month, and the H/K is only rated to 8Ohms so the DIII might be to low impedance[​IMG]. But on the bright side I got a really nice receiver.
    Ryan
     

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