Polyfill in a Sealed box questions...

mattldm · 07-28-2008

I built a 1.25 ft^3 sealed box for my Arc Audio Arc12 sub, and I plan on using some polyfill to stuff the box.

I bought a one pound bag of acousta-stuf and when I put it inside the box it doesnt even come close to actually "stuffing" the box. It all just sits in a lump on the bottom of the box.

Should I spread it out evenly and glue it to the sides of the box or will it make any difference if it is just loose and on the bottom inside the box?

thanks

Oliver · 07-28-2008

What would your goal be ?

Does this make the sound change at all ?

mattldm · 07-28-2008

Quote:

Originally Posted by a$$hole

What would your goal be ?

Does this make the sound change at all ?

My goal is to make it sound good, Duh!

I read a review on this sub that said it performed best in a 1.25ft^3 box sutffed with polyfill. So, I emailed Arc before I built the box and asked them about the size and the polyfill, and they told me that 1.25ft^3 & poly was "just about perfect".

So I just want to know if it matters if the poly is just lying the bottom of the box or should it be distributed evenly and glued in place!?

Oliver · 07-28-2008

yeah , try something

Do you know how to fluff it up ?

You are trying to change the box from adiabatic to isothermic

Play some music [ rap ]and listen to the sound

Does it sound better or worse , add some more , remove it , etc..,

GlasSman · 08-03-2008

It doesn't matter where it is.

As long as it doesn't get into the pole vent you're good....and you'd have to poke in with your finger....or other object.

bumpnzx3 · 08-06-2008

i prefer the "fluff" method as somewhat mentioned above- just slightly pull it in all directions just to make the mass of stuffing appear larger- then put it in the box.

Selkies · 08-06-2008

Is polyfill generally recommended?

mattldm · 08-06-2008

Quote:

Originally Posted by bumpnzx3

i prefer the "fluff" method as somewhat mentioned above- just slightly pull it in all directions just to make the mass of stuffing appear larger- then put it in the box.

It did exactly that. I spent about 20 minutes pulling all the fibers and stretching it out until it was much bigger than the box, then I sprayed a bit of 3M adhesive inside around the top and back of the box then stuffed the poly inside. It totally filled up the box and with the glue it shouldnt fall down into a pile over time.

BTW, the sub sounds great. Nice, tight low end and not "boomy" at all.

JoelM · 08-06-2008

Sounds like you are good to go then. You shouldn't need to "stuff" it, just loosely fill it like you described. I would just leave it as is.

donpisto · 08-06-2008

Any difference between fiberglass insualtion and polyfil? I've only used FG inuslation, never messed around with polyfil.

TurboFC3S · 08-06-2008

Quote:

Originally Posted by donpisto

Any difference between fiberglass insualtion and polyfil? I've only used FG inuslation, never messed around with polyfil.

Yes, very real differences. The Loudspeaker Design Cookbook does the best job I've seen yet of showing the differences. Regular Wal-Mart polyfill is generally the worst damping material, 1lb or 4lb fiberglass is much better.

ItalynStylion · 08-06-2008

Quote:

Originally Posted by TurboFC3S

Yes, very real differences. The Loudspeaker Design Cookbook does the best job I've seen yet of showing the differences. Regular Wal-Mart polyfill is generally the worst damping material, 1lb or 4lb fiberglass is much better.

what about acoustic open celled foam?

TurboFC3S · 08-06-2008

Quote:

Originally Posted by ItalynStylion

what about acoustic open celled foam?

It's better than plain dacron polyfill, but you almost certainly need more than a 1" lining on the walls. What the book shows is that a combination of foam and R19 1lb fiberglass works very well, as does a combination of acousta-stuff and fiberglass, or foam and acousta-stuff. But R19 being by far the cheapest, use it in combination with foam.

ItalynStylion · 08-06-2008

Good to hear...I'll be starting on some new enclosures today and I'll probably take your advice and stuff them as well as line them with foam. How would I ensure that the stuff doesn't get into the pole vent?

TurboFC3S · 08-06-2008

Quote:

Originally Posted by ItalynStylion

Good to hear...I'll be starting on some new enclosures today and I'll probably take your advice and stuff them as well as line them with foam. How would I ensure that the stuff doesn't get into the pole vent?

Some long staples to hold stuff in place, and/or hot glue a piece of panty hose over the pole vent.

**Boostedrex** · 08-06-2008

Quote:

Originally Posted by TurboFC3S

Some long staples to hold stuff in place, and/or hot glue a piece of panty hose over the pole vent.

Go figure that you'd be trying to get other guys to use panty hose. You better hope Heather doesn't find out. LOL!!!!!!!!

Seriously though, I didn't think that the stuffing getting into the pole vent was that big of a thing to worry about? Unless you shove it into the pole vent on purpose I don't know that I've ever heard of it just getting in there by itself.

TurboFC3S · 08-06-2008

Quote:

Originally Posted by Boostedrex

Go figure that you'd be trying to get other guys to use panty hose. You better hope Heather doesn't find out. LOL!!!!!!!!

Seriously though, I didn't think that the stuffing getting into the pole vent was that big of a thing to worry about? Unless you shove it into the pole vent on purpose I don't know that I've ever heard of it just getting in there by itself.

I'd have suggested you offer up some hose, but I know you only wear fishnet.

It's not really a problem, but if somebody thinks it is that'll give you a warm fuzzy feeling.