AR.COM Polyfill (again)

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  • 04-11-2006, 12:26 PM
    marduk
    AR.COM Polyfill (again)
    Hi,

    I finally got my speaker cabinets and ready to assemble my first DIY :-D

    I have a question though. How do I put the polyfill (acusta stuff)? I am confused by several forum posts regarding this matter. Below is one from EFE himself.
    Quote:

    Getting the right amount of polyfil in the DIY? EFE
    Jan 6, 2003 9:17 AM
    .....
    With the cabinet laying on its back, install just enough filler to fill about 1/3 to 1/2 the bottom of cabinet loosely (like cotton candy), spreading it all around including around the port. It will not settle if using the kind of loose polyfil sold in fabric stores for filling pillows or quilts! With the amount of filler I see in your picture, I would say your speakers will definitely lack bass in a big way. Try again and let us know how it goes? Thanks!
    Ed Frias
    EFE TECHNOLOGY Speakers
    What did he mean A, B, C or D (pls draw)?

    http://www.ilokano-unay.com/myfolder/polyfill.JPG


    Thanks
  • 04-11-2006, 02:47 PM
    kexodusc
    You may have to experiment, but in my experience (I've built 16 of these now) 2 or 3 inches of loose (not compressed) polyfill is sufficient. I think your picture "A" looks about right.
    I use my middle finger's knuckle as the depth gauge. When you take it out of the bag, fluff it the polyfill a tad, they tend to suck the air out of it and pack it a bit.

    Try to keep a decent amount of space behind the woofer. I like to "pull" the loose fill up along the side walls a bit.

    Don't worry, the wires will and drivers will hold it in place.

    You'll find with most speakers you build, stuffing is very much dependant on the driver, the cabinet size, whether it's a ported or sealed design, and personal taste. Don't be afraid to experiment a bit.

    Tip: If you do find it not holding in place, 3M (or any other brand) adhesive spray on the inside of the cabinet works great to help it stick.
  • 04-12-2006, 07:25 PM
    marduk
    Thanks Kexodusc!

    I assembled the parts in about 3 hours and have them connected to my RXV3000. The soundstage is absolutely amazing. Night and day difference from my old PolkR50. My Hsu sub sweetly blends at 50hz cutoff freq.

    Though I'm still in the process of breaking it in, I think it's too bright for me. I have the pre-assembled xover with a 5-ohm resistor to the tweeter. I read from the archives that EFE recommended 2-ohms instead. Does lowering the resistance suppress the brightness or is it the other way around?

    BTW, my cabinet is from www.diyspeakercabinets.com, and they look spectacular. I'll post some pictures when I get a better lighting.
  • 04-13-2006, 12:15 AM
    EFE Speakers
    Quote:

    Originally Posted by marduk
    Thanks Kexodusc!

    I assembled the parts in about 3 hours and have them connected to my RXV3000. The soundstage is absolutely amazing. Night and day difference from my old PolkR50. My Hsu sub sweetly blends at 50hz cutoff freq.

    Though I'm still in the process of breaking it in, I think it's too bright for me. I have the pre-assembled xover with a 5-ohm resistor to the tweeter. I read from the archives that EFE recommended 2-ohms instead. Does lowering the resistance suppress the brightness or is it the other way around?

    BTW, my cabinet is from www.diyspeakercabinets.com, and they look spectacular. I'll post some pictures when I get a better lighting.


    Marduk,
    The 5 ohm resistor built on the board is correct, but an additional 2 ohm resistor connected to the tweeter positive terminal is also needed as per my final instructions. Buy a extra pair of 2, 3 & 4 ohm resistors (10 watt) and crimp male and female quickdisconnects on each end so they can easily be installed and removed by simply pulling the tweeter at a later time. Of course the tweeter wires need to be long enough to pull out of the cabinet for changing the resistors later. The 2 ohm is the recommended standard, if you prefer a softer sound go to a 3 or 4 ohm resistors. The design of the DIY allows for adjusting the speakers to your equipment and environment, Madisound is still not explaining this feature to customers very well.

    I do not recommend soldering the changeable resistor to the tweeter, the heat can damage the tweeter terminals very easily, so use the male and female QC's at both ends. You'll need to shorten or fold the positive wire to the tweeter to make up for the extra length the resistor will add, and use a QC on that wire also for the resistor to plug onto.

    I also heat shrink the resistors to deaden the sound of them in case they touch the cabinet, but you can also wrap them with foam tape or insulation.

    Your "A' drawing is correct, success!

    Ed Frias
    EFE Speakers
  • 04-13-2006, 03:40 AM
    kexodusc
    Quote:

    Originally Posted by EFE Speakers
    Marduk,
    The 5 ohm resistor built on the board is correct, but an additional 2 ohm resistor connected to the tweeter positive terminal is also needed as per my final instructions. Buy a extra pair of 2, 3 & 4 ohm resistors (10 watt) and crimp male and female quickdisconnects on each end so they can easily be installed and removed by simply pulling the tweeter at a later time. Of course the tweeter wires need to be long enough to pull out of the cabinet for changing the resistors later. The 2 ohm is the recommended standard, if you prefer a softer sound go to a 3 or 4 ohm resistors. The design of the DIY allows for adjusting the speakers to your equipment and environment, Madisound is still not explaining this feature to customers very well.

    I do not recommend soldering the changeable resistor to the tweeter, the heat can damage the tweeter terminals very easily, so use the male and female QC's at both ends. You'll need to shorten or fold the positive wire to the tweeter to make up for the extra length the resistor will add, and use a QC on that wire also for the resistor to plug onto.

    I also heat shrink the resistors to deaden the sound of them in case they touch the cabinet, but you can also wrap them with foam tape or insulation.

    Your "A' drawing is correct, success!

    Ed Frias
    EFE Speakers

    Just to add to Ed's comments, you may wish to check that your crossover from Madisound doesn't already have a 2 ohm resistor in series with the tweeter, and after inductor. I've seen some odd variations of this xo from Madisound...I had ones with 7 ohm resistors...had to take them off and find a separate 5 and 2 ohm.
    I think they're pretty much following Ed's design now except with the 2 ohm resistor soldered on the crossover board (which adds an extra step to tweeter adjustments).