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Rudy J. You out there? *PIC*

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  • Rudy J. You out there? *PIC*




    I was wanting to add a couple of woofers to the Prisstinas. I think I found an interesting way to accomplish the goal.

    The surface area of a 15" woofer with either the same sensitivity as the Prisstinas or 3dB higher, depending on how you wire the woofers. 2 sets of 3 or 3 sets of 2. 3 sets of 2 puts your impedance at just above 4 Ohm. 3.5 cubic feet tuned to 24Hz.

    This arrangement keeps all the woofers closer to the mid for a better integrated phase alignment at the lower XO point. 600Hz and 4000Hz . . .

    What'cha think?
    R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
    Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

    95% of Climate Models Agree: The Observations Must be Wrong
    "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

  • #2
    Re: Rudy J. You out there?


    > I was wanting to add a couple of woofers to
    > the Prisstinas. I think I found an
    > interesting way to accomplish the goal.

    > The surface area of a 15" woofer with
    > either the same sensitivity as the
    > Prisstinas or 3dB higher, depending on how
    > you wire the woofers. 2 sets of 3 or 3 sets
    > of 2. 3 sets of 2 puts your impedance at
    > just above 4 Ohm. 3.5 cubic feet tuned to
    > 24Hz.

    > This arrangement keeps all the woofers
    > closer to the mid for a better integrated
    > phase alignment at the lower XO point. 600Hz
    > and 4000Hz . . .

    > What'cha think?

    A design Roy Allison might love...

    Comment


    • #3
      Re: Rudy J. You out there?


      > I was wanting to add a couple of woofers to
      > the Prisstinas. I think I found an
      > interesting way to accomplish the goal.

      > The surface area of a 15" woofer with
      > either the same sensitivity as the
      > Prisstinas or 3dB higher, depending on how
      > you wire the woofers. 2 sets of 3 or 3 sets
      > of 2. 3 sets of 2 puts your impedance at
      > just above 4 Ohm. 3.5 cubic feet tuned to
      > 24Hz.

      > This arrangement keeps all the woofers
      > closer to the mid for a better integrated
      > phase alignment at the lower XO point. 600Hz
      > and 4000Hz . . .

      > What'cha think?

      Looks really good!
      There's no problem with cavity resonances or such?
      If not than it's a GO!
      It would also look really neat with 3 of these ports across the bottom;
      <A HREF="http://www.madisound.com/cgi-bin/ind...18049&pid=1585">http://www.madisound.com/cgi-bin/ind...18049&pid=1585</A>

      Wouldn't even have to cut them!!!
      I'll go with the 4 ohm load.

      Comment


      • #4
        Re: Rudy J. You out there?


        > Looks really good!
        > There's no problem with cavity resonances or
        > such?
        > If not than it's a GO!
        > It would also look really neat with 3 of
        > these ports across the bottom;
        >
        > <A HREF="http://www.madisound.com/cgi-bin/ind...18049&pid=1585">http://www.madisound.com/cgi-bin/ind...18049&pid=1585</A>
        > Wouldn't even have to cut them!!!
        > I'll go with the 4 ohm load.

        If there aren't a problem with cavity resonances with MTM, there shouldn't be with this either. It doesn't have the small footprint usual to speakers these days, but after seeing Wayne and Curt's Exclamations, most don't seem to have a problem with a larger landing pad. I guess it's no bigger than a typical 12" sub.

        I like the idea of those ports . . . Otherwise, I'd put a 4" dia port in back.

        The only other option I'd have is WWWTMWWW and those outer woofers are really getting out there near one wavelength. And the cabinets are getting pretty tall too. I'm going to have to stew on that for a while I think.

        Have you tried porting the Prisstinas yet? I think you'll like it. LOW tune.
        R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
        Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

        95% of Climate Models Agree: The Observations Must be Wrong
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

        Comment


        • #5
          Re: Rudy J. You out there?


          > If there aren't a problem with cavity
          > resonances with MTM, there shouldn't be with
          > this either.

          OK, it's a go.
          Would that be 30 degree angles on the baffle?
          Also, can a biscuit jointer work with angles?

          I've got the ports for the Prisstinas but I've been way to busy on other stuff.
          Like today, fixing the furnace. I think the gas solenoid had a bad connection. I hope that was it and not the solenoid internals sticking.
          That'll be one tuff solenoid to remove and replace. I might just get a big ole hole saw and cut me an easy egress to it.
          Tomorrow it's the sewer pipes. Oh joy.
          It's been like this since last Monday.

          Comment


          • #6
            Re: Rudy J. You out there?


            > OK, it's a go.
            > Would that be 30 degree angles on the
            > baffle?
            > Also, can a biscuit jointer work with
            > angles?

            > I've got the ports for the Prisstinas but
            > I've been way to busy on other stuff.
            > Like today, fixing the furnace. I think the
            > gas solenoid had a bad connection. I hope
            > that was it and not the solenoid internals
            > sticking.
            > That'll be one tuff solenoid to remove and
            > replace. I might just get a big ole hole saw
            > and cut me an easy egress to it.
            > Tomorrow it's the sewer pipes. Oh joy.
            > It's been like this since last Monday.

            45 degrees on those sloping baffles. Keep it real easy. Also, stay well within the driver off-axis ability up to the XO point. 60 deg may be pushing it just a little.

            I played with the modeling of deeper offsets. It causes just a bit of a bump in the overall response above the XO point, easily fixed by lowering the mid output by a dB. The overall is about 88dB / 2.83V and should be able to soak up a boatload of power. If you put it in the low tuned ported, 75W to 20Hz
            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

            95% of Climate Models Agree: The Observations Must be Wrong
            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

            Comment

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