reducing box volume?

[wesl56 10+ year member]

ok so ive got this box.... 30x14x13, 2 seperate chambers for 2 12's... i wanna get 2 type R 12's and i really dont have time to design/build another box, so i't be great if i could just use this one.... however the net volume (after displacement) for each chamber in the box is 1.21 cubes...

alpine says gross sealed range is .7 - 1.0 ; optimum is .85 gross or .78 net

or for ported gross range .75 - 1.75 ; optimum 1.7 gross or 1.3 net (after port disp)

i figured adding 8 .75x2x12 braces to the inside of my box is only going to add like .0xx cubes; not really enough to bring me into optimum range for sealed...

so im just wondering what would you suggest i could do (without building/buying a new box)... either add something (foam or whatnot) to reduce volume, or just cut some holes and drop in some prefab ports (i think sealed would sound better tho)... thx

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[prochobo 10+ year member]

Polyfill

 

[guy022077 10+ year member]

doesnt polyfill make the box "bigger" because it slows down the air? just put some wood in the box to take up the space

 

[tRiGgEr 5,000+ posts]

Polyfill will not decrease the percieved box volume, rather increase it.

Just throw in as many 2x4's are needed to decrease the volume. Secure them to the bottom of the box.