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  • #16
    Originally posted by billfitzmaurice View Post
    He's not going to get it with that woofer, unless it's used in a set of mains along with a good sub or two.
    Exactly the arrangement I pointed out earlier - they *should* work well in the right enclosure with the right port and right crossover.

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    • #17
      Steve Lee Somewhere through this build or another, their lifelike portrayal of percussion is mentioned. The drivers are very affordable, not to mention this guy's woodwork is top-notch. http://techtalk.parts-express.com/fo...mp-tower-build
      http://techtalk.parts-express.com/fo...khanspires-but
      http://techtalk.parts-express.com/fo...pico-neo-build
      http://techtalk.parts-express.com/fo...ensation-build

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      • #18
        Originally posted by Kornbread View Post
        Steve Lee Somewhere through this build or another, their lifelike portrayal of percussion is mentioned. The drivers are very affordable, not to mention this guy's woodwork is top-notch. http://techtalk.parts-express.com/fo...mp-tower-build
        Wow!

        What a fantastic link/thread!

        Thanks, man!

        :D

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        • #19
          Originally posted by Chris Roemer View Post
          If you'd digested almost ANY "beginner" book (like SpeakerBuilding 201) you'd know that basically ALL drivers that employ a voice coil have an impedance plot that starts down low (typically referred to as the driver's "Re"), then rise to a peak at the driver's resonant freq. (Fs). This is VERY normally between 30-60Hz for a woofer (you've got no need to be concerned about this AT ALL) and maybe around 1k-3kHz for a tweeter.
          After that there's a fairly broad "valley" of low impedance (often near 200Hz for a woofer / 4k? for tweeters) with a consistent "rise" up to 20k. The distance up to 20k isn't that far away on tweeters (and is generally ignored) but it's a long way up there from 200Hz, so it's often beneficial to run a "Zobel" across a woofer's terminals (about $2?) to effectively flatten out the rise. (You can get by w/out this on the GW woofer - IF . . . )
          That woofer/tweeter combo should work well enough.

          Your "generic" 2k XO CAN be used effectively, BUT you need to add 3 components to it (2 resistors and a cap - to each XO).
          As Geoff pointed out, that woofer DOES have a bad peak at 3k (look at the FR plots to see it). You can snub that by paralleling the iron-core coil with a 4n(ohm) resistor in series w/a 2uF cap.
          The other noted problem (of the tweeter being too loud) can be remedied by adding a 4n resistor between the amp's "+" lead and the entrance side of the tweeter's 5uF cap. That should do it. (you do NOT want that resistor feeding the woofers coil - so you might have to do some surgery on the XO board)

          I'd tune the box to the low 40s (yielding an F3 below 40Hz - FINE for music!) by using either a 2" "Precision Port" that's 4" long, or make your own 3"id x 10" long port out of PVC or a cardboard tube.

          Hard to get a "tower" (usually w/the tweeter at LEAST 36" off the floor) from only 0.85 cu.ft. Either stands are in order, or a larger box w/a false bottom half (that's closed off).


          Chris, your advice was spot-on.

          I have modified the XO as you suggested and had to cut the solder trace entering the tweeter cap to isolate it with the 4 Ohm Resistor but it worked perfectly (I placed an 8 ohm L-pad in there [wiper to one-end] and adjusted it while monitoring its resistance and I settled upon your value of 4 ohms) Good call!


          Additionally, I placed the suggested 2uF cap in series with another 4 ohm resistor across the inductor after figuring out which of the two coils were in play and, Man! That took the harshness right out of the hot peak around 3KHz..

          Everything is alligator clip-lead assembled on a roll around bench right now but I will get the new components attached, insulated/glued soon.

          These speakers have never sounded this good and are about 0.5 CuFt with a 2-3/8 X 5" port tube in the back.

          They are very clear and will play louder than I can bear and are still clean/punchy.

          Thanks for taking the time for this.

          Thanks to everyone else who offered assistance as I used all of it.




          Steve.


          Next project . . .

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          • #20
            Thought I would add some pics of the mods so that others might follow along more clearly:


            I cut the solder trace leading to the tweeter capacitor using a Dremel tool:

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            Then I tested the circuit mods by using alligator clip-leads to attach the components to the board and connect to the speakers:

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            Soldered the components to the board - 1:

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            Another view of both completed board modifications:

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            Cheers!




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            • #21
              Glad everything worked out for you.
              Don't forget a pic of the final project ...

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