Can one stuff a subwoofer, that uses a radiator with poly-fill? - AVS Forum
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post #1 of 12 Old 03-27-2013, 07:33 PM - Thread Starter
 
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I've been reading about the benefits of stuffing the subwoofer box with poly-fill but I haven't found anything which addresses issues surrounding how stuffing a ported box, w/radiator will affect the output.

The subwoofer box is a 2ft^3, Klipsch built box with a 12", Dayton driver and radiator. The purpose of the exercise is for my personal edification.

Are there any precautionary procedures I should concern myself with or should I just stuff away at the rate of 1.5lbs/cuft?

Should I make a squirrel cage out of 1/2 mesh hardware cloth the size of the driver/radiator to create a sort of tunnel effect and stuff the rest of the box.with poly-fill at the above rate?

I've been surfing the web regarding this issue for the better part of this afternoon and currently looking at pricing of Parts-Express, Acousta-Stuf polyfill vs poly-fil available from Amazon dealers. Research gives me conflicting stories regarding yes, it does make a difference as to damping ability and no it doesn't make a difference as the difference is too little to matter when all other things are considered.

Can you guys suggest anything regarding the matter of poly-fil material choices and the act of stuffing a ported box with a radiator?

Thanks In Advance.
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post #2 of 12 Old 03-27-2013, 07:44 PM
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Line the walls, same as a ported design.



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post #3 of 12 Old 03-27-2013, 07:54 PM - Thread Starter
 
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Then I should create a squirrel cage the size of the driver/radiator, stuff the area outside the squirrel cage and I should be good?

Any suggestions regarding Acousta-Stuf vs Poly-Fill? I wanted to put in an Amazon order tonight in hopes of getting the stuffing and speaker gasketing material by Friday.
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post #4 of 12 Old 03-27-2013, 07:55 PM
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I am no expert on the subject but here are my thoughts.

Stuffing a box is usually only done with sealed enclosures, especially undersized ones where the goal is to reduce the systems Q minimizing a peak in the bass response. With ported/passive radiator subs the insides are usually lined with material but not stuffed. Stuffing a ported enclosure reduces the efficiency of the port as all that material gets in the way of the air which need to move freely inside the enclosure for the port to work effectively. By lining the walls with 1-2" of absorptive material like polyester batting the goal is to dampen harmonics and other driver noises inside the enclosure that are not present in the signal from re-radiating out through the cone or port.
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post #5 of 12 Old 03-27-2013, 08:06 PM - Thread Starter
 
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Quote:
Originally Posted by mtg90 View Post

I am no expert on the subject but here are my thoughts.

Stuffing a box is usually only done with sealed enclosures, especially undersized ones where the goal is to reduce the systems Q minimizing a peak in the bass response. With ported/passive radiator subs the insides are usually lined with material but not stuffed. Stuffing a ported enclosure reduces the efficiency of the port as all that material gets in the way of the air which need to move freely inside the enclosure for the port to work effectively. By lining the walls with 1-2" of absorptive material like polyester batting the goal is to dampen harmonics and other driver noises inside the enclosure that are not present in the signal from re-radiating out through the cone or port.

Thanks. That's the idea behind the squirrel cage (tunnel) as then both driver and radiator will be free of extraneous poly-fill and the rest of the box will be stuffed.

Any insight as to choice of poly-fill as I'm ready to put an order in so I can have it by Friday.
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post #6 of 12 Old 03-27-2013, 08:16 PM
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I think they are quite similar, a lot of guys just grab cheap pillows and pull the stuffing out or even just throw the whole pillow casing and all into the enclosure.
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post #7 of 12 Old 03-27-2013, 08:21 PM - Thread Starter
 
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Quote:
Originally Posted by mtg90 View Post

I think they are quite similar, a lot of guys just grab cheap pillows and pull the stuffing out or even just throw the whole pillow casing and all into the enclosure.

Now that's how I like to do it. biggrin.gif

Thanks! I will now hit the "place your order" button. biggrin.gif...biggrin.gif Order is in.

This is the poly-fill ordered.

This is the half-inch gasketing tape ordered. The overall shipping was "MUCH" cheaper through Amazon than by going through Parts-Express' check-out system.

Figure while taking the sub apart, I might as well replace the gasketing tape. cool.gif

-
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post #8 of 12 Old 03-27-2013, 08:58 PM
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I use pink insulation, it works and its cheap. 



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post #9 of 12 Old 03-27-2013, 09:07 PM - Thread Starter
 
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Originally Posted by Mrkazador View Post

I use pink insulation, it works and its cheap.

Thanks. With the exception of the glass particles getting everywhere, I read a lot of good things regarding R-19, pink insulation. When working inside the subwoofer case with the pink insulation, how well do you do with fiberglass particles getting everywhere?
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post #10 of 12 Old 03-27-2013, 09:24 PM
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I would not use fiberglass in a ported design. Bill Fitzmaurice doesn't like using pink insulation because it can get inside the driver. I havent seen any reports of  damage caused by fiberglass but you never know...



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post #11 of 12 Old 03-27-2013, 11:51 PM
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You SHOULD use some damping material to deaden interior sound reflections for both sealed AND ported enclosures.
Any soft sound absorbent material will do including gray egg crate foam or old blue jeans. Pink insulating fiberglas is OK too. I have used it
and have never found a noticeable amount of glas fiber in, on, or around the drivers or inside the box.
The speakers end up sounding "better" with the stuffing.
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post #12 of 12 Old 03-28-2013, 03:34 AM - Thread Starter
 
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Mrkazador and LINEARX, thanks for the thoughts.

From what I gleaned online, stuffing the box with poly-fil will increase the reach of the sub by a few Hz which, for me, would be fabulous as currently the rebuilt pair of subs we have are strong to 23Hz.

Currently inside each of the boxes are a couple of pieces of poorly fitted one-inch grey foam for top and bottom damping. IMO, the addition of the poly-fill will be a damping upgrade over what is currently in each of the boxes. And while I'm in the box, I figure I'll check the speaker gasketing as I don't recall when the driver/radiators were replaced if each came with their own gasketing or if I installed them unsealed.

In ignorance, if I have a choice, it will usually be the wrong one. tongue.gif
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