stuffing your sealed boxes

do you guys stuff your sealed boxes with like pillow stuffing?  what kind of difference does it make for the box, and how much of the stuff do you at in the box.  I have heard of doing this but just have never done it to my boxes and i would like to know if there are any gains to doing so.

-------------
Imagination is more powerfull than knowledge

I might be wrong I don't know?  I read a while back when you stuff the box with fiberfill or pillow stuffing it tricks the sub into thinking its in a bigger bigger box than it is.  I have not built a lot of boxes, but I've read a lot on building boxes.  I hope I was able to help.

-------------
Respect the Blood Line

yea...it slows down the soundwaves or something like that.  i posted it in your other topic, but just cut some up and roll it up and staple it in the corners to keep it away from the sub.

It actually cools the air inside the box. When aire is pressurised, it's heats up, and the polyfill helps disapate the heat, thereby making the box seem larger.

It does do what it's supposed to, but there is a point of diminishing returns, where you overstuff the box and the polyfill looses it cooling properties.

What I usually do is just line all the sides with 1 layer of high loft batting.

Paul

If you fill the box with the correct amount of polyfill after you make a box to the manufacturers specs or whatever you came up with, wouldn't that kind of negate the point of having a "right" number of cubic ft.?  I don't know jack about this other than a rule of thumb is 1lb for each cu. ft. of space.  It just seems like you would ruin all your hard earned calculations if you "added" space to the box.

-------------
"I'm Rick James bi***, enjoy yo' self Ah Ah Ah"
Dave Chappelle as Rick James

I have had good experiences with going slightly larger than mfr. suggestions. Usually their suggestions are absolute minimal requirements and are used as marketing ploys.



-------------

thats awesome...thanks for the link  Luckydevil. 

fugit] wrote:

---

If you fill the box with the correct amount of polyfill after you make a box to the manufacturers specs or whatever you came up with, wouldn't that kind of negate the point of having a "right" number of cubic ft.?  I don't know jack about this other than a rule of thumb is 1lb for each cu. ft. of space.  It just seems like you would ruin all your hard earned calculations if you "added" space to the box.

---

The fill is included in your calculations.  When you use a speaker box design program, you tell it how you'll be filling the box and the program takes that into account.  See Unibox, WinISD Pro...  Also, most good speaker manufacturers will give a recommendation of box volume including a fill amount, such as fully filled, loosely filled, walls lined, etc.  If you're not using a design program, follow the manufacturer's advice for volume and fill amount.

This is a snapshot of a part of the Unibox program.  The damping factor shown here can be scrolled from no fill, minimal fill, walls covered, to heavy fill.  Each choice changes the absorption characteristic of the box with a given value for Qa.  The program accounts for this characteristic when plotting the response.

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

That link has some good information but it is wrong to think of this technique as "fooling" the woofer.  Woofers don't "think," therefor they cannot be "fooled."  It's no trick and it's not magic, it's physics.  Sound is a pressure wave through a medium (in this case air.)  Sound inside an enclosure (or more accurately the pressure wave off the back of the speaker) must move through the air inside the enclosure.  Acoustic fill inside an enclosure means the air must travel through it as well as through the air.  In effect, the fill creates many small passages that the air must travel through rather than simply going straight from the speaker to the back of the enclosure.  It takes longer to go through the many small passages, JUST LIKE it takes longer for the air to bounce off the back wall of a larger enclosure than it does off the back wall of a small one.  No fooling or tricking anything, no magic, by adding fill you actually physicaly increase the effective size of the enclosure.

-------------
Support the12volt.com

where can you get the unibox program at.  and thanks for the explanation it makes way more sense to me now

-------------
Imagination is more powerfull than knowledge

Here you go.  Get Unibox and others here.  They work using MS Excel spreadsheets, so if you have MS Office installed you've got it made.

https://www.pvconsultants.com/audio/frdgroup.htm

Or, here's a program that doesn't require spreadsheets:

https://www.linearteam.dk/default.aspx?pageid=winisdpro

-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.