the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

Poly-Fil box stuffing?


Post ReplyPost New Topic
< Prev Topic Next Topic >
glacious 
Member - Posts: 13
Member spacespace
Joined: September 06, 2005
Location: United States
Posted: September 06, 2005 at 3:29 PM / IP Logged  
I recently constreucted a new box out of 3/4 MDF for my Rockford Fosgate Stage One Subs. I built it to the best of the specs the sub required, and I guess it turned out good. It hits a whole lot harder than my old box, but then a friend of mine told me that if i stuffed it with some filling, that it would help it to hit harder. I found some stuff called Poly Fil and at 13 dollars a pound, I am not sure if it is really worth it. I mean I have a Rockford Fosgate P5002 pushing them, and I just think that they can't handle the power. Not to mention that I added a Power Cap as well, and well I don't think that the filling would help much or would it?? That is my question. I am also considering maybe upstaging to the Stage 2's which really don't handle that much more power, but maybe that is my problem. Bottom line is, my system hits, but not to my xpectations, so should I use some filling in the box or should I just get the Stage 2's. Thanks for the help...
jp
geepherder 
Platinum - Posts: 3,668
Platinum spaceThis member consistently provides reliable informationspace
Joined: October 27, 2003
Posted: September 06, 2005 at 5:15 PM / IP Logged  
Check to see if Rockford recommends using stuffing.  Some manufacturers do- JL, for example.  Basically what stuffing does, is slow down the air that's moving inside the box, to simulate a larger volume (bigger box). 
My ex once told me I have a perfect face for radio.
redpeppers 
Silver - Posts: 483
Silver spaceThis member has made a donation to the12volt.com. Click here for more info.spacespace
Joined: May 24, 2005
Location: United States
Posted: September 07, 2005 at 12:00 AM / IP Logged  
poly fil is only need it box is too big or too small for subs spec.
Where theres is a wire there's a way.
stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: September 07, 2005 at 7:24 AM / IP Logged  
redpeppers, I like your sig line :)  But if the box is too BIG how is polyfil going to benefit?  If it's too big one should physically reduce the volume with a solid fill like a brick or a block of wood, or another interior baffle, or more bracing.  If it's too small by more than 10% of the RANGE of volume needeed for the woofer to perform properly, the box should be rebuilt.  But, as long as the box volume is in the proper range, polyfil can be used to enhance the quality of the tone.  It is easily removed if the results aren't satisfactory...
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
placid warrior 
Silver - Posts: 357
Silver spacespace
Joined: November 06, 2004
Location: Canada
Posted: September 07, 2005 at 7:15 PM / IP Logged  

geepherder wrote:
Basically what stuffing does, is slow down the air that's moving inside the box, to simulate a larger volume (bigger box). 

Allright...can someone PLEASE clarify what the fill does!  Origionally this is what i was telling people too, makes sense....but another topic which had a link where some guy used an MLSSA analyzer to measure impedence of 3 different enclosures stated that  "the air inside your enclosure actually heats up as your woofer moves, making the air stiffer.  When the enclosure is stuffed with fiber, the fibers wiggle, dissapating some of the heat and making the system work as though the box were larger"

Poormanq45 
Silver - Posts: 597
Silver spacespace
Joined: October 27, 2004
Location: United States
Posted: September 07, 2005 at 9:35 PM / IP Logged  
[;acid: Of course the air is going to heat up. There's usually a few hundRED / thousand watts going through a voice coil, which is like 1~2% efficient. ~98% of that electricity is going directly to heat.
Now, about the poly fil wiggling: WTF is that guy smoking?
stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: September 07, 2005 at 11:12 PM / IP Logged  

(Poorman, another doozie!!  We're still waiting for your answer to how resistors will lower current flow in THIS TOPIC.  The guy's not smoking anything.) 

placid warrior:  both answers are essentially based on the same principle.

I first read about the fibers of the polyfil vibrating when I ordered AcoustaStuf and read the paper insert in the package.  It told (IIRC) of how these specifically-designed fibers reacted to the air flow in a way more beneficial than regular polyester fill.  The reaction was a vibration as the fibers dissipated the energy of the sound waves.

Now, this post led me to do a quick search through the Web for more specific information, and so please look at

In the first, look at this line:

When a sound wave strikes an acoustical material the sound wave causes the fibers or particle makeup of the absorbing material to vibrate. This vibration causes tiny amounts of heat due to the friction and thus sound absorption is accomplished by way of energy to heat conversion. The more fibrous a material is the better the absorption

In the second is a description of Isentropic flow (which is way past me but not past some of the others who frequent this forum...)

The third is geared more toward my level of intellect and I will point you specifically to the section titled "Friction".  In it you'll see that friction causes a liquid (including the gas:  air) to slow down when it passes over a rough surface.

This should help clear up how polyfil makes a box volume seem larger.  The air, indeed, is slowed down because of friction, and the polyfil "wiggles" as it absorbs energy and dissipates it into heat.  At least, it clears it up for me!

(...glacious - $13 lb for polyfil is high.  You should be able to get regular polyfil for $5 or less per lb.)

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
mrmsudawgs 
Copper - Posts: 145
Copper spacespace
Joined: February 22, 2005
Location: United States
Posted: September 08, 2005 at 10:36 AM / IP Logged  
Let's keep it simple. Buy some polyfill at Wal-Mart - the stuff they put in pillows - for about $3.00 for a huge bag. Jump in your vehicle and set your volume level to where it is bumping pretty hard. Make a mental note of how every thing sounds - maybe use a meter to take a few db measurements. Now, turn everything off, remove your subs from the enclosure, pack some polyfill in and repeat the test. Notice any difference? If so, good! If not, well - there you have it. :>)
Mike
2000 F150 Supercab Lariat, Alpine CDA-9831, Polk MMC570 in Doors, One Polk MM2104 Sub, One Polk Carbon C400.4 Amp.
John 3:16
DYohn 
Moderator - Posts: 10,741
Moderator spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: April 22, 2003
Location: Arizona, United States
Posted: September 08, 2005 at 11:25 AM / IP Logged  

stevdart wrote:
(Poorman, another doozie!!  We're still waiting for your answer to how resistors will lower current flow in THIS TOPIC.  The guy's not smoking anything.) 

I answered that one for you, Steve.  Poly-Fil box stuffing? -- posted image.

Support the12volt.com
glacious 
Member - Posts: 13
Member spacespace
Joined: September 06, 2005
Location: United States
Posted: September 08, 2005 at 5:33 PM / IP Logged  

Simple enough I think. The specs for the speakers in a sealed box, are from .75 to 1.25 cubic feet of air. The box I built is about +/- 1.13 cubic feet of air. So I don't think the box is too small. But then again, if it was smaller than the speakers specs. then it would be a nice tight bass. But in this case..it has the boom...boom. Like a loose boom, but not muddy boom. Maybe I just have the wrong size box..LoL. For what its worth, mrmsudawgs, I guess I will just take your advice and try it and see what happens.  And thanks to everybody else's opion. I appreciate all the help..

By the way, does anybody have any thing good or bad to say about the Stage Two Subs?? I might just need to upgrade...

jp
Page of 2

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Friday, March 29, 2024 • Copyright © 1999-2024 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer