4th order underseat box build!!!!!!!

[KR banging]

Ok I have a 04-08 supercrew f150 with a seat lift kit installed. Will be putting in 2 skar zvx 8d2. With the 4th order box right now I have 1:1 ^3 sealed to ported. I have been doing lots of studying on Pollyfill. There is a proven method of using IM-SG SMD to measure the gain of ^3 with adding Pollyfill to a box the video was done by demore engineering. They added Pollyfill to a box and added 20% more box volume by adding Pollyfill. the problem is I don't know how much Pollyfill they added to achieve 20% volume increase. So what I'm trying to accomplish is after adding Pollyfill to sealed section having my box volume 1.3^3 for both subs giving me perfect sealed size for the subs which will give me closer to 1:1.5 ratio of sealed and ported then Pollyfill the ported section with the end result close to 1:2 ratio of sealed to ported. I've had multiple people tell me I'm crazy but numbers are saying it can be done if someone knows how much Pollyfill= ^3 % gain.

 Thanks in advance!!!

[Triticum Agricolam]

So you can put up to about 1.25 lbs per cubic foot of polyfill in a box. Usually around 1 lb per cubic foot is a good place to be. 

Now understand, stuffing a box with polyfill is NOT THE SAME as making the box bigger.   Stuffing a box lowers its Q, the same thing happens when you make the box bigger and that is what they measured with the IM-SG in the video you saw. The difference is a larger box raises efficiency, stuffing a box gerenally lowers efficiency.  Less efficiency equals less output.  There are some exceptions but generally speaking that is what happens. 

 

If I understood you correctly it sounds like you intended to stuff the ported side as well? That WILL NOT WORK, at all.  Stuffing a ported box kills output. 

[Triticum Agricolam]

Also, while I admire your creativity, under the seat is not the place to use a bandpass box. If you have the space for a bandpass box you will be MUCH BETTER off with a well done ported box. 

[KR banging]

Thanks for the reply! I will look into how I can do a ported box while having the subs covered so they don't get kicked or anything being under the seat.

 

[vpine057]

My Brother had a custom box built for him along time ago, where they built a sealed enclosure for 2-12" kicker solos (when they were round) and stuffed the poly in it. Then built another box for that sealed box too slide into, and port out the top and sides. It was in a trunk of a 94'Camary but man did that shit hit. I don't know how much poly they used but that shit was stuffed in their like sardines.