OG BudBone Posted March 1, 2012 Report Share Posted March 1, 2012 I stumbled upon this while reading up on some enclosures. Stuffing a sealed box with a fibrous material can increase the low end output apparently. Is this really true? I've never heard of this. Itd be nice considering I don't have any room for a bigger or ported box Quote 1997 Trans Am WS6 Pioneer DEH-P5200HD 2 DC Level 4 M2 12s 4 cubes tuned to about 34hz DC 3.5k 1/0 Welding Supply Ultra Flex Stock 140A alt Stinger Fuses & Fuse Holders XS Power D5100 XS Power XP3000 Link to comment Share on other sites More sharing options...
MrSkippyJ Posted March 1, 2012 Report Share Posted March 1, 2012 It worked for me, or at least it seemed to work for me! Quote F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
Jlan Thr Smth Posted March 1, 2012 Report Share Posted March 1, 2012 (edited) its maybe the easiest way to "increase" the volume. it actually alters the rate that the air inside the box changes temperature. lets use a sealed box as an example- when your cone is at rest, the pressure inside the box is considered ambient. when the cone goes in, the pressure inside the box goes up. when you pressurize air, the temperature goes up. when the cone goes out, the pressure inside goes down, and temperature goes down. we're not talking about a couple of degrees, its generally a very small temperature change. but once you add polyfill or fiberglass insulation, or something of that sort, it absorbs and radiates the heat at a different rate than just air. its a slower rate very similar to having more air, just like having a bigger box. it only works because there is so much surface area in proportion to mass, and finer materials tend to work better. But the problem is it reaches diminishing returns quickly and will only work up to a certain point. Last time I looked into stuffing it was about 1 lb/ft^3 Edited March 1, 2012 by Jlan Thr Smth Quote Link to comment Share on other sites More sharing options...
OG BudBone Posted March 1, 2012 Author Report Share Posted March 1, 2012 Very interesting. I read that it increases output up to 40%. I might give this a try. Where would I get the material. An also, is it subwoofer safe? I don't want to burn em up due to lack of ventilation haha Quote 1997 Trans Am WS6 Pioneer DEH-P5200HD 2 DC Level 4 M2 12s 4 cubes tuned to about 34hz DC 3.5k 1/0 Welding Supply Ultra Flex Stock 140A alt Stinger Fuses & Fuse Holders XS Power D5100 XS Power XP3000 Link to comment Share on other sites More sharing options...
Jlan Thr Smth Posted March 1, 2012 Report Share Posted March 1, 2012 Very interesting. I read that it increases output up to 40%. I might give this a try. Where would I get the material. An also, is it subwoofer safe? I don't want to burn em up due to lack of ventilation haha I don't know about 40% but pillow stuffing or known more specifically as PolyFill can be purchased from walmart/craft stores for cheap. Yes the subwoofer is safe I wouldn't worry about anything burning up. I don't recall where it starts hitting diminishing returns.. I would start off at 1 lb/ft^3.. Someome could chime in probably. It will not increase the volume a whole lot but in some cases it can really help with the low end.. I would tell you to not get you hopes up too high as the change in sound may be minimal. Quote Link to comment Share on other sites More sharing options...
MrSkippyJ Posted March 1, 2012 Report Share Posted March 1, 2012 40%, very doubtful. i use the pillow stuffing that walmart sells. and they sell it in 1lb bags too! Quote F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
Sanitarium Posted March 1, 2012 Report Share Posted March 1, 2012 Wow..... Ok yeah, the poly fill would have an extremely small effect on tempterture differential but is NOT what's causing the desired effect. What's causing the desired effect is a decrease in standing waves. The back waves from the cone are dispersed and slowed down, causing the driver to act as if it's in a slightly bigger box while maintaining the compression needed for cone control at high excursion. Quote Link to comment Share on other sites More sharing options...
Jlan Thr Smth Posted March 1, 2012 Report Share Posted March 1, 2012 Wow..... Ok yeah, the poly fill would have an extremely small effect on tempterture differential but is NOT what's causing the desired effect. What's causing the desired effect is a decrease in standing waves. The back waves from the cone are dispersed and slowed down, causing the driver to act as if it's in a slightly bigger box while maintaining the compression needed for cone control at high excursion. Not to call you out, but to get standing waves especially at such low frequencies wouldn't the volume of the car have to be huge? You really don't see standing waves in a car... more in home audio.. From what I've read stuffing is based soley on the principle of accoustical energy being turned into thermal energy, albeit very small change. Quote Link to comment Share on other sites More sharing options...
Sanitarium Posted March 1, 2012 Report Share Posted March 1, 2012 Wow..... Ok yeah, the poly fill would have an extremely small effect on tempterture differential but is NOT what's causing the desired effect. What's causing the desired effect is a decrease in standing waves. The back waves from the cone are dispersed and slowed down, causing the driver to act as if it's in a slightly bigger box while maintaining the compression needed for cone control at high excursion. Not to call you out, but to get standing waves especially at such low frequencies wouldn't the volume of the car have to be huge? You really don't see standing waves in a car... more in home audio.. From what I've read stuffing is based soley on the principle of accoustical energy being turned into thermal energy, albeit very small change. yes, you can still get standing waves inside a sealed box at low frequencies. imagine a bathtub full of water and the waves on the water are hitting the edges, coming back, hitting the opposite edge, and coming back, etc. Should give you a good visual of what's going on inside a sealed box. Quote Link to comment Share on other sites More sharing options...
OG BudBone Posted March 1, 2012 Author Report Share Posted March 1, 2012 Hmmm great stuff guys, thanks for the input we'll do you guys think it would be worth the trouble? I'm really lacking on the low end Quote 1997 Trans Am WS6 Pioneer DEH-P5200HD 2 DC Level 4 M2 12s 4 cubes tuned to about 34hz DC 3.5k 1/0 Welding Supply Ultra Flex Stock 140A alt Stinger Fuses & Fuse Holders XS Power D5100 XS Power XP3000 Link to comment Share on other sites More sharing options...
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