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02-21-2006, 03:30 AM | #1 | |
AF Newbie
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Polyfill in subwoofer enclosures
Can anyone please tell me how much polyfill should be used per cubic feet. Ive been lookin all over for an answer for that. can u please help me out.
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02-21-2006, 07:37 AM | #2 | |
AF Enthusiast
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Re: Polyfill in subwoofer enclosures
Any amount from fully stuffed to just lined. The more you add the SLIGHTLY larger the enclosure will seem.
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2002 Ford Explorer Limited D31 yellow top Kenwood DDX-7017 2 Ascendant Audio Avalanche 18's 13 cuft NET ported box tuned to 27hz Autotek Mean Machine MX3000.1 Ascendant Audio Arco component set Orion 275SX (Mids) PPI Art Series A200 (tweets) Poly Mids for rear fill to come soon. |
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02-21-2006, 09:08 AM | #3 | |
Banned
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Re: Polyfill in subwoofer enclosures
If you add 1lb of poly fill for every cubic foot of space, your subwoofer will act like the box is 1/3 bigger.
1ft^3 + 1lb polyfill = 1.33ft^3 that the speaker "see's" 3ft^3 + 3lbs polyfill = 4ft^3 that the speaker "see's" Make sense? |
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02-21-2006, 01:07 PM | #4 | |
AF Enthusiast
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Re: Polyfill in subwoofer enclosures
So if I put 3 lbs of poly fill into a 1ft^3 box would the speaker act like it was in a 2ft^3 box? or even if I went big and used a 4ft^3box with 8 lbs of poly fill. Would the speaker think it was in a 6.66ft^3 box? Or can you only put 1 lb of poly fill per ^3??
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02-21-2006, 03:37 PM | #5 | ||
Banned
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Re: Polyfill in subwoofer enclosures
Quote:
If you were to graph the effectiveness vs. amount it would look more like a geometric curve than a linear line, if that makes any sense. I think that's right. I know the 1lb/ft = 33%+ is correct though. |
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09-29-2009, 11:21 PM | #6 | |
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Re: Polyfill in subwoofer enclosures
1 lb. of pollyfil to 1 cu. ft. box size.
Pollyfil tricks your sub into thinking it's in a bigger box by about 30%. What this process really does is highers your Q. Qtc - value for the damping provided for a driver in a sealed enclosure. Denotes the enclosures ability to control the driver response at resonance. Qtc = 0.707 is the optimum value for sealed enclosures, providing flattest response and highest SPL for deep bass extension. Enclosures for this value are often rather large. Lower Qtc can give even better transient response, down to a Qtc of 0.577 for the best damping and transients, but the enclosure is usually huge and SPL's are down. A Qtc of 1.0 is a compromise between deep bass and transient response vs. smaller sized enclosure. Larger subs can go with an even higher Qtc, as their resonant frequency is often very low, but Qtc's above 1.5 can begin to sound very muddled and boomy, and sacrifice deep bass extension and transient response for enhanced mid-bass peaks (louder). I have a 3 cu. ft. sealed box with 12 in. subs in it. The inner volume of the box is slightly smaller because of the space the magnet of the subs take up. I added about 2.7 lbs. of pollyfil on all sides of the box. I notice a tighter bass sound. I don't know why, but this process caused my subs to hit way harder at a much lower amp gain. Before the polyfil my amp gain was turned up 3/4's the way, almost full power from the amp. Now that the polyfil is in I have to put my gain at less than half. I guess the positive side of this, is my amp only pushes half the wattage to slam the same bass as it did before. I may have gained a db. or 2 louder. It gave me more of a tight mid bass sound that is clean, rather than boomy. |
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09-30-2009, 05:18 PM | #7 | |
Audio Guy
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Re: Polyfill in subwoofer enclosures
this thread is 3 years old, the people no longert even post here
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