Should I match woofer and tweeter sensitivities?

Discussion in 'Archived Threads 2001-2004' started by VinhT, Mar 23, 2002.

  1. VinhT

    VinhT Second Unit

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    For my DIY satellite speakers, I don't have the technical know-how to build my own crossovers, so I'll be buying pre-made ones from Parts Express. Since using a stock crossover means I can't add little resistors or whatnot to customize the output of the drivers, I've become concerned that the tweeter may become overbearing. Should I attempt to find woofers and tweeters with the same sensitivity levels to achieve a more uniform response level? Also, do wattage rating differences matter as well (like if the woofer is 40W, but the tweeter is 80W, etc)?

    Thanks for any input.
     
  2. Travis G

    Travis G Stunt Coordinator

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    I'm not sure because I have never tried. Infact I have never built any fullrange speakers, although I plan on doing so as soon as I can afford to. For now I am still learning. I think you would be hard pressed to find a woofer as sensitive as most tweeters. You will need to use an adjustable L-pad. This is not a gain control. Your XOs will not opperate properly if you just add a variable resistor. An L-pad attenuates the high-pass section without altering the impedance seen by the amplifire.
    FWIW, I would get a kit with an XO pre designed for the drivers. There is no such thing as a universal crossover, and the generic ones do not take into account many driver/crossover interactions that can affect the sound quality drastically. You can alternatively pick up a copy of the Loudspeaker Design Cookbook and learn about designing XOs. It's not brain surgery but it's not exactly easy either. If you choose to go this route be prepared to do alot of homework. David B. Weems wrote a book I read that was a little less complicated than the LDC. I think it was called "Designing and Building Your Own Stereo Speaker Systems".
    I hope that I haven't discouraged in any way and that you find this helpfull. Maybe you will even be encouraged to learn more. This forum is the best home theater forum on the internet IMO and there are people here that can answer most of the questions would have. Just don't be affraid to ask.
    Travis
     
  3. Jon Torres

    Jon Torres Second Unit

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    What DIY speakers are you going to use? The adire av3s play full range and would not need a crossover. I don't think building a crossover is that difficult. Just follow the schematic. There are lots of people here that can help. I built my first kit last december or so and just finished another pair. Now I want to start another one. It's a real bad addiction. I think the pre made crossovers at PE is a bad idea.
    Take a look here
    http://www.hometheaterforum.com/htfo...threadid=56518
     
  4. ThomasW

    ThomasW Cinematographer

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    I'd strongly suggest NOT using generic XO's.

    For a speaker system to work properly the drivers must first be individually measured in a test baffle. Those measurements are then imported to a XO modeling program. Then a XO designed specifically for the the measured drivers can be modeled and constructed. The drivers and assembled XO are then mounted into the real box and final adjustments are made while testing with a accurate measurement system like Clio.

    So if one doesn't have the necessary equipment and knowledge to do this; it's a really a much better idea to buy a kit where everything pretested and engineered.
     
  5. VinhT

    VinhT Second Unit

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    Well shucks. I had my heart pretty set on staying away from DIY kits (they're too massive for a small room) and just doing my own novice-level two-way speakers. After much searching, I did manage to find a 5" woofer and 1" tweeter from PE with the same sensitivity level of 89. Using WinISD, I found decent response could be had in a small enclosure. Then I was hoping to use a stock crossover from Parts Express and get something relatively acceptable. But, after hearing the advice given here and reading The Reverend's articles on crossovers, I suppose the dream is postponed until I get my hands on the loudspeaker bible by Vance Dickason. [​IMG]
    For now I guess I'll have to try something with the Adire AV3s.
     
  6. David A. Frattaroli

    David A. Frattaroli Stunt Coordinator

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    You can include an attenuation network circuit in your cross over to match sensitivities between tweeter and driver.
     
  7. Patrick Sun

    Patrick Sun Moderator
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    And you might as well read up on Baffle Step Compensation while you're doing the research...
     

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