Subwoofer Stuffing?

[moves]

Hello - I've searched but couldn't seem to find a solid answer.

What should I stuff my sealed 18 inch passive cabinet with and how much material should I use? Stuff it tight? Just line it with an inch of material?

Thanks for your input.

A

 

[William Lemmerhirt]

https://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317
Should say on this page. I think...

 

[William Lemmerhirt]

1/2 lb per cubic foot.

 

[lovinthehd]

I've seen 1 lb per cuft more often recommended as a general guideline and what I've used....

 

[lovinthehd]

I picked up a couple boxes of this on sale a while back. Local fabric store or cheap pillows are also often used as sources by diyers.

 

[everettT]

Walmart sells pillow stuffing dirt cheap FWIW. I've used spray adhesive to keep it attached to the walls.

 

[William Lemmerhirt]

I've seen 1 lb per cuft more often recommended as a general guideline and what I've used....

Agreed. I just mentioned that as PE gives it for a recommendation.

 

[William Lemmerhirt]

I picked up a couple boxes of this on sale a while back. Local fabric store or cheap pillows are also often used as sources by diyers.

Or this...

Walmart sells pillow stuffing dirt cheap FWIW. I've used spray adhesive to keep it attached to the walls.

I have done this exactly. Works good.

 

[lovinthehd]

Before I bought the polyfil I just used some old pillows I had....

 

[lovinthehd]

While not specifying weight/volume ratio interesting article on lining/stuffing subject https://data-bass.com/data?page=content&id=79

 

[moves]

So pillow fill material works well? No need to get the specific acoustic poly fill stuff? I'm spending $2500 CAD on my DIY subwoofer build and I want to do it right.

 

[lovinthehd]

So pillow fill material works well? No need to get the specific acoustic poly fill stuff? I'm spending $2500 CAD on my DIY subwoofer build and I want to do it right.

Many pillows are stuffed with polyfil...

 

[moves]

Many pillows are stuffed with polyfil...

I get that but my question is... is the pillow polypill different than this as it is marketed as acoustic stuff poly fill and not for pillows...:

https://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317


It's ok I did some research and I learned that the parts express product has a different crimp to the material compared to the pillow stuffing... anyhow, I got a 5 lb bag of it... that should do.


Ugh... just remembered that I am building 2 so I need a 10 pound bag.

 

[lovinthehd]

I get that but my question is... is the pillow polypill different than this as it is marketed as acoustic stuff poly fill and not for pillows...:

https://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317


It's ok I did some research and I learned that the parts express product has a different crimp to the material compared to the pillow stuffing... anyhow, I got a 5 lb bag of it... that should do.


Ugh... just remembered that I am building 2 so I need a 10 pound bag.

When I looked at that and diyer comments came to conclusion very similar at least if not the same.

 

[fuzz092888]

Personally, when I stuff my subs, I do rockwool lining all sides, subtract their volume from the cabinet and then stuff 1lb/cuft with polyfill (pillow stuffing). I've used more expensive stuff, but I haven't gotten a measurable or hearable difference when you line the walls with rockwool to start. I daresay my recent build is understuffed, but with rockwool lining it really helps kill vibration.

 

[moves]

Personally, when I stuff my subs, I do rockwool lining all sides, subtract their volume from the cabinet and then stuff 1lb/cuft with polyfill (pillow stuffing). I've used more expensive stuff, but I haven't gotten a measurable or hearable difference when you line the walls with rockwool to start. I daresay my recent build is understuffed, but with rockwool lining it really helps kill vibration.

So 1.5 inch rockwool and then just make your cabinet 1.5 inches larger than intended?

 

[fuzz092888]

So 1.5 inch rockwool and then just make your cabinet 1.5 inches larger than intended?

No no, I subtract the voume of the rockwool from the internal volume of the sub and then stuff 1lb/cuft.

 

[moves]

No no, I subtract the voume of the rockwool from the internal volume of the sub and then stuff 1lb/cuft.

So same cabinet size just smaller internal volume due to the lining of rockwool.... Since this is changing the internal volume, doesn't this change the entire physics of the cabinet since cabinets are supposed to a specific size based on the woofer's data?

When stuffing the polifill, do you glue it to the rockwool (or the sides of the cabinet if not using rockwool ) or do you stuff it loose in the cabinet?

 

[TLS Guy]

Hello - I've searched but couldn't seem to find a solid answer.

What should I stuff my sealed 18 inch passive cabinet with and how much material should I use? Stuff it tight? Just line it with an inch of material?

Thanks for your input.

A

For a sub, you don't really have to worry a lot about internal reflections, as the wave lengths are too long. For sealed enclosures you need to fill the cabinet with the stuffing, but there should be absolutely no compression of the material.

The effect will increase enclosure volume 25 to 30%. This is allowed for in programs bake Bass box. Rockwool may be best but it is nasty stuff. Polyfill I have used without trouble and is probably best for TLs.

 

[fuzz092888]

So same cabinet size just smaller internal volume due to the lining of rockwool.... Since this is changing the internal volume, doesn't this change the entire physics of the cabinet since cabinets are supposed to a specific size based on the woofer's data?

When stuffing the polifill, do you glue it to the rockwool (or the sides of the cabinet if not using rockwool ) or do you stuff it loose in the cabinet?

It isn’t changing the internal volume because rockwool is semi permeable. It’s not different than stuffing so it doesn’t change anything, it’s just more effective at dampening reflections and vibrations while taking up less space. However, it’s much more expensive and annoying to work with, so I use as little as possible and simply line the walls and cover with grill cloth. A cost no object sub, I’d cut the rockwool into smaller pieces and individually wrap each with grill cloth and stuff with those in addition to lining.

I like the polyfill go free. Most of the big manufacturers do the same and they and I have never run into an issue with this. I even built a sub with rockwool and didn’t cover or line it and it still worked fine for over 5 years until I pulled the driver to rebuild.