Full range: 4 vs. 9 drivers and total output...

Discussion in 'Home Theater Projects' started by Kenneth Harden, Dec 14, 2005.

  1. Kenneth Harden

    Kenneth Harden Screenwriter

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    ...I have a ton of those $.50 4" full range Parts Express drivers they blew out.

    I want to make some speakers, and am debating the use of 4 or 9 drivers (those can get me to a nice 8 ohm load), or some other configuration.

    First question: How much will total SPL output change between using 4 and 9 drivers?

    I want to do a stereo pair in a ported or sealed box (leaning towards a ported box).

    Second question: How come when you have more drivers in the same size box, the bass extension DROPS? With 4 drivers in a 1500 cu. in. box, WinISD says it will go WAY lower than with 9 drivers. Is this because there is more air moving in a smaller box, and it isn't as good for low bass? Are there ways around this?

    Thanks!
     
  2. Dave Poehlman

    Dave Poehlman Producer

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    That's because the drivers are acting like one larger driver with a higher Vas.

    Vas: "The volume of air that offers the same degree of restoring force on the cone as that of the cone's suspension."

    So, you'll need a bigger box to get more extension out of 'em.

    Do you have the part no/specs for those drivers?
     
  3. ThomasW

    ThomasW Cinematographer

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    Slightly more than +3dB from acoustic coupling.

    No more Xmax than those drivers have you better go ported.

    Don't expect any bass from 4" drivers unless you plan on using dozens and dozens of them.
     
  4. Rory Buszka

    Rory Buszka Supporting Actor

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    I'd say go with the nine, vertically arranged drivers. You should be able to give them a good 30 watts without trouble, and they'll be pretty loud. You will, of course, want a subwoofer to fill in the low end, though.
     
  5. Kenneth Harden

    Kenneth Harden Screenwriter

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    If I can get to 80-100 Hz., I will be happy, I know I need to use a sub.

    I was also thinking a staggered design, like:

    o_
    _o
    o_
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    o_
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    o_
     
  6. ThomasW

    ThomasW Cinematographer

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    Put them in a line.

    Here's a thread about some mods that make them work better
     
  7. Andrew Pratt

    Andrew Pratt Producer

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    Happy Birthday Thomas!
     
  8. ThomasW

    ThomasW Cinematographer

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    Hi Andrew,

    Actually there's me ThomasW, and different HTF member Thomas(space)W

    My birthday is in April...
     
  9. Andrew Pratt

    Andrew Pratt Producer

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    :b
     

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