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Old 5th April 2010, 05:08 PM   #11
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Originally Posted by xiayu View Post
Can you explain to me how it works?
I will say up front that I am no expert on speakers or acoustics, so I may well be wrong about how I think it works.

If the effect of stuffing was thermal, the popular view, then the best stuffing material would be the one with the highest thermal transfer rate. That should be something (of the commonly used stuffings) like fiber glass, not wool. If it is thermal, then stuffing the box with #400 steel wool would work better than wool or poly fill.

My thinking is that the stuffing reduces the density of the air in the sealed box by displacing some of the air. Less dense air is more compressible, making the box look larger to the driver. The figure of 10% might be the point at which the volume of the stuffing begins to dominate this effect. Just my thoughts. I am not in a position to prove or disprove either method of action.
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Old 15th December 2012, 07:13 PM   #12
Pavelow is offline Pavelow  Canada
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hold on here. one second... so. the goal with box stuffing is to make the air appear less dense to the driver... well.. why not just create a vacuum inside the box and replace the air with helium? could something like that benefit a subwoofer? couldn't that make like a 1 cubic foot enclosure look like it's bigger? like instead 1 cube, 2 cubes? I've also read that the speed of sounds travels like 3 times faster through helium or something like that. *mindblown* ..... so?
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Old 15th December 2012, 08:15 PM   #13
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Quote:
Originally Posted by Pavelow View Post
hold on here. one second... so. the goal with box stuffing is to make the air appear less dense to the driver... well.. why not just create a vacuum inside the box and replace the air with helium? could something like that benefit a subwoofer? couldn't that make like a 1 cubic foot enclosure look like it's bigger? like instead 1 cube, 2 cubes? I've also read that the speed of sounds travels like 3 times faster through helium or something like that. *mindblown* ..... so?
To make the box seem larger you need to use denser gas -- as done by Michael Dayton-wright with SF4 (?)

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Old 15th December 2012, 11:51 PM   #14
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when it comes to box stuffing material type can be controversial.
but as to proper amount i like David B. Weems philosophy and test.
whether it's sealed or bass full reflex full range or sub stuffing is applied for two main reasons adequate excursion control (return from Xmax) and damping of higher frequency harmonic distortion created by the box.
the test is simple a 1.5 V battery and a switch.
you simply listen for the sound at make and break of the switch as in make should sound like a defined thud/click and then at break if it sounds like boom or a woosh that would indicate under damped.
i have used this method time and again on speakers of all kinds especially on car subs that are notoriously underdamped (saving many an amp from an untimely death)
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Old 8th March 2014, 01:03 AM   #15
DRB is offline DRB  United States
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I have a bookshelf speaker that has a 12 inch x 12 inch x about 1 inch (uncompressed) square of Dacron. I am going to experiment with a certain brand of acoustic foam that has a nice absorption curve and was just going to play around with a couple of different pieces inside. Does looking at RAL absorption curves mean anything? Also, I was told that Polyfill was more to change the Q and acoustic foam was to be placed along the cabinet wall to dampen the cabinet. The Dacron piece that's inside my speakers inside aren't lining the inside of the cabinet, they are just stuffed inside. My bookshelf's aren't transmission line speaker, they are just small bookshelf speakers that aren't ported.
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Old 17th September 2014, 07:46 AM   #16
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This thread is old but just for the benefit of whoever stumbles upon. http://www.nousaine.com/pdfs/Box%20Stuffing.pdf
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Last edited by availlyrics; 17th September 2014 at 07:51 AM.
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