SA-WM40 Polyfill? (1 Viewer)

[Brian_Tho]

I love this subwoofer it really has a smooth sound. I got it based on the reviews from this and other forums. Also went to best buy and ran a demo test between the jbl $799 and the sony I honestly think the Sony sounded better, but what do I know. My question is I got the polyfill from Wally Mart, I used a half bag. Is this to much or to little on the polyfill. Thanks for the help

 

[Jose G]

Check this out: Link Removed

 

[David Hartsock]

link doesn't work.

 

[Jose G]

Sorry about the link not working- it seems they're under construction. It a great article but has tables that will not format when i try to cut and paste it. Here's some info though from another post:

"Rule of thumb for 100% stuffing is 1 lb of Acousta Stuff or polyfill, per 1 cubic ft of internal cabinet air space less driver and port. This is of course usually used to fool the driver into seeing a larger internal volume in SEALED subs than is really their. It can be used in a ported design also...

... if you do add fill start slow (small amount 1/2 lb or so) and make sure to keep it clear of the slot and driver!"

I'll see if I can get that original article on here. if not's it's called "Make a small box act like a larger one with polyester fiberfill By TOM NOUSAINE

 

[Jose G]

Yeah, the link is down- I've attempted to get the article from another site, but they are all linked to the same page that appears to be underconstruction. Hope the last info helps.

 

[Joe Szott]

Brian,

Just as an FYI I did the same with 2 SW40s and ended up using 1 whole poly fill bag for each. Hehe, that being said, Wal Mart had 2 bag sizes, so if you bought the bigger one than 1/2 a bag would be the same amount.

Basically, I just laid the polyfill against the 3 walls that didn't have either: the speaker, the amp, or the wires. You don't need to pack the sub cabinet full, just get it nice and resonably padded in there.

Been using these subs for 6 months, great sound and absolutely no problems whatsoever from the polyfill modification.

 

[Brian_Tho]

Yeah Joe thanks for the info. I love this sub I am glad that I didn't buy an expensive subwoofer first. I would have been mad. This unit kicks butt!!

 

[David Hartsock]

This information narrated from a article by Tom Nousaine
Car Stereo Review, March/April '95
Polyfill (Dacron/polyester fiberfill to be technical) is that filler you can purchase that is used for pillows to give them that filled/soft feeling, or used within fiberglass insulation, or long-fiber wool. Polyfill can also be used in woofer installations to fool the woofer into thinking it is in a larger enclosure.

What does this mean? Well, effectively, if you can't squeeze the properly sized box into your vehicle, you can build a smaller enclosure and still (possibly) receive the same amount of bass as a properly sized enclosure.

How does it work? When your woofer is moving, the air inside the enclosure will heat up which makes the air "stiffer". When polyfill is in the enclosure, the air causes the fibers to move which in effect dissipates some of the heat within the enclosure. This can effectively increase the "seen" box size by up to 40%. Of course, this is an optiumum number. Using too much may had the reverse effects

How do I use it? Per the CSR article, there are a few fules of thumb that may be followed: For enclosures that are a maximum 3cf of internal airspace, using 1.5lb of fill per cubic foot of internal airspace should net a 30% increase in box volume without any major performance issues. For larger enclosures, using 1lb of fill per cubic foot can boost the enclosure by about 25%.


The following charts give a breakdown of the test results of this test:

Sealed Enclosure
1.4-ft Box
Stuffing Density
(lb/ft ) System Resonance
(Fsb) Effective
Size Percentage
Gain

0 56.6 1.4 --
0.70 53.0 1.6 14%
0.75 52.7 1.7 21%
1.50 51.7 1.8 29%
1.75 50.8 1.9 36%
2.60 50.4 1.6 14%
3.10 52.6 1.2 -14%



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

Sealed Enclosure
5.1-ft Box
Stuffing Density
(lb/ft ) System Resonance
(Fsb) Effective
Size Percentage
Gain

0 42.0 5.1 --
0.25 42.0 5.1 0%
0.50 41.2 5.8 14%
0.75 40.3 6.2 22%
1.00 39.4 6.5 27%
1.25 38.6 6.5 27%
1.50 40.2 5.6 9%




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

Ported Enclosure
1.4-ft Box
Stuffing Density
(lb/ft ) System Resonance
(Fsb) Effective
Size Percentage
Gain

0 42.0 1.4 --
0.40 39.1 1.6 14%
0.85 37.2 1.8 29%
1.25 35.2 1.9 36%
1.40 34.2 2.0 43%
1.75 35.2 1.9 36%