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Discussion Starter · #1 ·
Hello Everyone, if you have read my previous posts you know that I just picked up a used Klipsch RW12D yesterday. It sounded great at the persons house and sounds good at my house but when I am at very close range to the subwoofer or have just the subwoofer on alone I hear what I can only describe as what it would sound like if there was a wire or piece of trash touching the cone. I don't know if this makes sense. There is plenty of bass coming out of the sub. I played The Polar Express and at the begining with the train scene the entire house shakes but when I get within 12-18 inches from the sub I can hear a little rattle. The rattle sounds like as if something was touching the cone. I openend it up and there is nothing touching it. I push the cone in and out by hand and don't feel any rubbing. It is only when the bass hits. Any thoguhts? Is the voice coil going back, could it be a setting on my receiver or sub its self? I have it set to 80hz. I tried a different wire.
 

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sounds like a bad capacitor on the amp...had a polk sub do the same thing. almost sounded like the dust cap was vibrating against the cone, turned out to be a bad power capacitor. Replaced both 35volt units with 50volt and bam like brand new again.


I have read a few having amp problems with those subs, so if its not the port being lose then its probably what i mentioned aove.
 

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Discussion Starter · #4 ·
Thanks for the help folks, I am extremely disapointed. This sub has some serious potential. I don't know about caps, I know what they look like but I would have no way of telling if its bad or not. I still want this sub. I think I am going to try and take it to a local shop and see if they can do something about it. I know the air port is not loose, neither is the emblem. I am just mad that the guy that sold it to me didn't have the decency to at least mention it.
 

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This sounds like the port baffle is loose, stick you hand in the port, wiggle it around, if it moves then its loose, if not then its somehing else, when you slide your hand in you can feel were it connects.
 

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Discussion Starter · #8 ·
Thanks guys, I double checked all the screws and the port it is not loose. I wish it was that easy. Even at very low volume where you the subwoofer is not even moving back and forth you can hear a bit of a scrape like noise. I definitely think either the sub is bad or the amplifier. I wish I know how to check the sub and amplifier separate.
 

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Discussion Starter · #9 ·
FIXED!!! I don't know what I did but I took it apart, checked the amplifier for loose screws. I noticed there where a few loose screws on the amplifier. Some of the screws where to brackets that held down electrical components. They where loose. I also tightened everything inside, including zip-tying the wires together to make sure they where not rattling. I also crimped down the connector to the subwoofer to make sure they where not coming loose and making a bad connection. Turned it up this morning and the noise is gone. This thing is a beast. I love it.


One thing I did notice is that when I opened it up, the inside is bare wood. Even my cheapo Yamaha subwoofer had insulating material inside. So since I don't ever leave well enough alone, I am wondering if adding some insulation would improve sound? Any thoughts on this? Maybe spray on insulation like the Dynamat stuff?
 

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Quote:
Originally Posted by cessna1466u  /t/1470611/klipsch-rw12d-blown-just-purchased#post_23264027


One thing I did notice is that when I opened it up, the inside is bare wood. Even my cheapo Yamaha subwoofer had insulating material inside. So since I don't ever leave well enough alone, I am wondering if adding some insulation would improve sound? Any thoughts on this? Maybe spray on insulation like the Dynamat stuff?

Absolutely, yes there will be a measurable difference. Adding insulation decreased the output a few Hz and improved interior noise. I used this poly-fiber A bit pricey and my understanding, less expensive product will get you to the same place. I filled two Klipsch, subwoofer boxes (SW-12 II) that already had two one inch foam sheets installed; one for the top and one for the bottom half. I placed the fill between the foam pads and the wood sides of the box's interior.


You mentioned you don't have any foam inside the box. Make sure you're not plugging up the port as I don't see that as a good thing. Maybe somebody can comment on that as I don't have proper insight regarding what happens when one stuffs the subwoofer port with Poly-fil.


I used maybe a pound of fill for each box that are a bit larger than the RW-12d. The overall response was lowered from a measured (using REW) 25Hz down to a measured, 22Hz. The addition of a third RW-12d, brought us down to a solid 19Hz.


Now you have me curious and I'll need to open the newest subwoofer and see what's what with it's inside and see if I need to stuff this turkey as we have plenty of poly-fill to use.
 

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Discussion Starter · #11 ·
We have that exact one at our local Wal-Mart for $24.97 for a 10lb carton. I have not seen it in person but is is just like the fill inside stuffed animals? If so did you just literraly "stuff it"? Just remover the speaker and fill the inside with about 1lb of this stuff? Is there no concern with the stuffing touching the amplifier circuits? Does the amp not get hot. My amp is not protected at all on the inside. I am also considering getting one of those Auralex Subdude for the bottom. My floor is a raised wood subfloor with carpet and our homes where not made very well. I can actually move the drywall and feel it being off the studs by about 1/8". All my walls rattle with this subwoofer going.
 

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Discussion Starter · #14 ·
How would I keep the poly-fill from touching the amplifier? Do I just add it to the bottom and maybe staple some to the top and sides? Would I better off with something that sticks like Dynamat? I realize that the Dynamat helps more with the walls of the sub box not rattling and the poly-fill does something different. So is the increase in sound quality with polyfill work the risk of doing it wrong?
 

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Quote:
Originally Posted by cessna1466u  /t/1470611/klipsch-rw12d-blown-just-purchased#post_23264230


How would I keep the poly-fill from touching the amplifier? Do I just add it to the bottom and maybe staple some to the top and sides? Would I better off with something that sticks like Dynamat? I realize that the Dynamat helps more with the walls of the sub box not rattling and the poly-fill does something different. So is the increase in sound quality with polyfill work the risk of doing it wrong?

Perhaps someone like Bill Fitzmaurice or Mark Seaton will chime in, but in laymen's terms when you add polyfill to a box you are effectively slowing the soundwaves as they move through the box which effectively results in a smaller enclosure thinking it is larger.


With a ported or vented enclosure, it is designed speficially in regards to:

- The driver characteristics

- The size of the enclosure

- The tune desired (18hz tune, 20hz tune, 30hz tune, etc).


This tune and enclosure size determine the vent/port diameter and length. If you start adding polyfill or other insulation you could negatively affect your tune. I would hesitate in doing this unless you can measure response.


What I have seen DIYers with ported enclosures do is line the interior walls with egg crate material (mattress topper) that is about 1-2" thick. Spray on adhesive on the interior side walls then attach. Or something like this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-520
 

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Being a cretin, I just smeared the poly-fil all over everything; amplifier and wires. I made a tube out of the one inch foam sheets and the space between the created tube and the walls was unceremoniously stuffed. I can't fine the images I used as a guide but I did have pictures.



We have ported subs that use radiators, hence why I created an interior tube configuration. From what I recall, if one has a sealed sub, just fill the box up and be happy. Of course, leave room for the subwoofer driver.


Using pink batting works a treat also but one then has issues regarding fiberglass dust.


-
 

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Quote:
Originally Posted by cessna1466u  /t/1470611/klipsch-rw12d-blown-just-purchased#post_23264270


Thanks ACK, what effect does anything this eggcrate stuff do? Does it do the same as the polyfill?

I have never done it myself (only built sealed subs), but my understanding is that lining the sub results in "dampening" of the sound reflections. The DIY subforum would be a good place to search and ask.
 

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If you haven't the facility to measure the output for a baseline and your subsequent changes, you're going to run around in circles and prolly end up with a bunch of stripped screw-holes.

You've stopped the rattling, and I'm sure that's a genuine improvement, so why not leave it be and just enjoy the sub? You're ahead at this point, it'd be a pity to ruin that.
 

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Discussion Starter · #20 ·
Oliver, I like the way you think. You are right those screws are tough. I am always scared my hand is going to slip and I am going to puncture the surround of the subwoofer. I will be opening it one more time to secure the port tube. At the very end of the tube it looks like there are screw holes on each end, almost as if the tube was supposed to be secured to the back of the box but it is missing a 1" x 1" piece of wood to to attach the tube too. I am attempting to post a pic of it here. Lets see if it works.
 
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