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Polyfill in a non-WM40 sub?


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10 replies to this topic

#1 of 11 OFFLINE   James Grasso

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Posted April 15 2003 - 09:56 AM

I've got a Velodyne VX10 on the way and was just thinking about how I've only seen the polyfill mod done on the Sony SA-WM40 sub (which I have done myself). Why is this? Is it the only one with the real boomy problem? Could it benefit/impair the VX10 when it arrives, or has no one tried or researched it yet?

#2 of 11 OFFLINE   Brian Bunge

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Posted April 15 2003 - 02:26 PM

James, I doubt that many people have heard this sub yet so anything I or anyone else that hasn't heard it can say would be complete speculation. What I can tell you is that it is possible that adding some polyfil may help the sub if it does sound boomy. It does so by increasing the apparent volume of the enclosure and lowering the tuning frequency. Since you've moded the Sony before you know what to listen for. So have a listen and see what you think. If it is boomy there's no reason not to give the polyfil a shot.
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RAD Home Theater

#3 of 11 OFFLINE   James Grasso

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Posted April 15 2003 - 03:04 PM

Yeah, I was just seeing if anyone had tested the VX10 with or without the polyfill and if anyone stuffs any other subs frequently. I know I've only really read about the WM40 being modded this way. Going to add some super cheap "custom" spikes (actually archery field points and t-nuts) to both of them and see if that helps tighten everything up even more. The Velodyne should be here soon as well as the replacement WM40 amp, so I'll get some comparisons up as soon as I can. BTW, what software, etc. can I use to make up graphs of frequency response?

#4 of 11 OFFLINE   Brian Bunge

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Posted April 15 2003 - 03:30 PM

[quote] BTW, what software, etc. can I use to make up graphs of frequency response? [quote]

You mean to plot the frequency response of the subs when you test them with an SPL meter? I use Excel as do many other people. So if you have that you can use it or any other software that is similar.
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RAD Home Theater

#5 of 11 OFFLINE   James Grasso

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Posted April 15 2003 - 03:44 PM

Fair enough, now I just have to run to RadShack soon and get a sound meter. I think I'll try with several tests with no mods, with only poly, with only spikes, with both, etc. and see if anything "fun" happens.

#6 of 11 OFFLINE   David Lawson

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Posted April 16 2003 - 04:53 AM

Brian, perhaps you can answer some poly-fil questions for me as well. My main concern lies with heat dissipation for the internal amplifier. The WM40's amp is in a different "chamber" from the woofer, but this isn't the case in my new JBL PB10. Should the poly-fil be kept away from the amp? If so, will bass response be affected if one side of the enclosure has more poly-fil than the other?
He obviously misinterpreted what it means to "be bullish."

#7 of 11 OFFLINE   Brian Bunge

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Posted April 16 2003 - 05:36 AM

David, I wouldn't worry about heat dissipation unless you stuff it really heavily. I've never had an amp die on me but I remember someone here did. Whether or not it was directly due to the polyfil I don't know.
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#8 of 11 OFFLINE   David Lawson

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Posted April 17 2003 - 04:10 AM

Thanks for the reply. What about poly-fil touching the woofer assembly itself? Since the PB10 is a downfiring sub, I'll have to find some way of suspending the poly-fil from the "ceiling" of the enclosure. Should I make sure that none of it touches the woofer assembly, or is that also not a concern?
He obviously misinterpreted what it means to "be bullish."

#9 of 11 OFFLINE   Brian Bunge

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Posted April 17 2003 - 04:20 AM

I wouldn't worry about it too much. I've used polyfil in downfiring subs without any trouble. You could always use the polyfil that's in sheets and lay it over the magnet so nothing actually gets down in there.
Brian Bunge
RAD Home Theater

#10 of 11 OFFLINE   Rajeev_s

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Posted April 17 2003 - 04:41 AM

Keep us posted James. I would like to know your results when you do polyfil on your sub. I also have a VX-10. I love it so far. I dont think its boomy, but this is my first sub. I would like to know if it will benefit from polyfil mod. Thanks

#11 of 11 OFFLINE   Jeffrey R

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Posted April 17 2003 - 11:55 AM

I just picked up a Velodyne VX-10 from a 6th Ave. electronics retail store last night. In limited listening so far, I am very impressed. It is nice and tight and musical for music, and it is impressive for HT. I need to give it more critical listening in both music and HT, but for $170, it definitely meets or exceeds expectations.




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