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Discussion Starter #1
Wondering if using something besides polyfill in my sub box would be better and cleaner. I found small polyfill fibers in my subs when I removed them from my last box. I was thinking of lining the corners with modeling clay, using some Dynaxorb pads directly behind the 2 subs and then using acoustic foam in the rest thoughts??????

Here's the foam I was going to use:
Parts-Express.com:Acoustic Foam 1-1/2" 24" x 18" UL 94 | foam acoustic foam damping dampening dampening foam cabinet foam egg crate convoluted sonic impact
 

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Thassa whatta I'ma gonna do, too... Found a whole roll of it for 5 bucks!
 

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:confused:

Specially designed, opened cell, flame retardant foam in a convoluted "egg crate" pattern. Helps to reduce muddy bass and cleans up the midrange by absorbing internal standing waves. Staple or glue to the top, bottom, sides and back of your speaker cabinet.
How is that the same function as polyfill?
 

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Well... If you mean for it to "make your sub feel like it's in a bigger box", then I dunno...
I just want to see if the acoustic egg will clean things up even more for my Mag V4... Right now it's just bare wall MDF inside.
 

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Take the highest possible note played by the sub...say 100 hz and determine the wave length. Then divide that by 4. If the foam thickness is less than that number it won't have a significant enough effect on the back wave.

Also, absorption is velocity-dependent. So more velocity = more chance for absorption. The wave velocity is lowest as it's starting to develop off the back of the driver. This is why absorbers work better away from the sound source.

IMO, if adding open cell foam changes the total Q of the box like polyfill is supposes to do, then it would be worthwhile. This may be why some report a change in sound when they line boxes with foam because it's pretty difficult to absorb a huge wave and foam is generally not dense or heavy enough to block it.

I'm on board with mass loading the thing with clay, though. :)
 

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Discussion Starter #10
Good info here, I found an old article by Tom Nousaine in Car Stereo Review where he did some comparisons on boxes with poly fill and without. I am going to go read it. There were some other things at Parts Express that I could use too:

Sonic Barrier Dampening Mats:
Parts-Express.com:Sonic Barrier 1/2" Acoustic Foam w/PSA 18" x 24" | acoustic damping foam black hole sonic barrier acoustic foam damping foam damping sonic impact sonic110408

Acoustic Dampening Foam:
Parts-Express.com:Acoustic Damping Foam | acoustic damping foam black hole sonic barrier acoustic foam damping foam damping sonic impact

Or there's good old Acousta Stuf
Parts-Express.com:Acousta-Stuf Polyfill 1 lb. Bag | sound dampening sound polyfill fiber enclosures enclosure dampening bass bag ac


What about Dynaxorb or De-Flex pads I never used them what's the consensus on those

PE is 10 minutes away from me so I could go check out the stuff first hand.
 

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Is there some type of issue you're trying to remedy by doing this? What exactly do you hope to achieve? As far as I'm concerned, a nice sturdy enclosure built to spec for your sub is all you need to be concerned with.
 

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Discussion Starter #12
Is there some type of issue you're trying to remedy by doing this? What exactly do you hope to achieve? As far as I'm concerned, a nice sturdy enclosure built to spec for your sub is all you need to be concerned with.
The box will hold two JL 10W6 (v1's) powered by a JL 500/1 I just want the deadest, best sounding enclosure I can get. I've always used polyfill but I was concerned when I found fibers when I removed the subs from the previous box.
 

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Discussion Starter #14
The fibers can damage the voice coils if they were to get inside of their. Interesting article by Tom Nousaine in an old CSR mag. I'll try and scan or print what he had to say.
 

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you could always apply some wire mesh to protect the VC,
glass fibre gives better absorption, but at very low frequencies, nothing does very much.
 

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I think that works well sonically, but it might not hold up.
I have seen some nice enclosures lined with recycled cotton insulation, though.
 

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I've always used fiberglass with the paper backing removed.
 

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In the spirit of "DIY" how about carpet padding? I do not mean the foam types but a needle/fiber based type. Anyone used this with success.
 
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