When talking about enclosure sizes, is that net or gross?

[bubbagumper6]

Like when a manufacturer (specifically FI) recommends a 2.5 cubic foot box, is that gross or net?

Just wondering, because I'm still trying to design my box, and right now it's like 3 cubes, but after port and woofer displacement it's more like 1.75 :P

[kfx450r]

thats net

[bubbagumper6]

well that *****, lol

[spl_robb]

what you want to tune your box to
i guess is for 1 12"

16 x 23 x 18 3cuft (2.98)


sub. displacement =.18 or .16( fi BTL or Q)
slot port dis. for 33hz=.89 using 3 x 14.5 port(43sqin) 28.5 long

2.98-(.16+.89)= 1.95net.cuft



same box dif. sqin of port.
slot port dis. for 33hz=.77 using 2.5 x 14.5 port (36sqin) 28.5 long

2.98-(.16+.77)= 2.05net.cuft


you need to do a 3.5 box or tune higher

[bubbagumper6]

Yeah I know, I'm working on it

[bubbagumper6]

Ok got some new results...

Best I could do, with what little space I have

Gross: 3.15
Net: ~2.25
Port: 16.5x2.5 = 41.25 square inches
Length: ~32 inches

[spl_robb]

you can go smaller port (2x16.5)and save some cuft,you dont need that much port area with 30-35sqin OK, and the port will be shorter for that same 32hz


still 2.25cuft sounds ok

[bubbagumper6]

Isn't more port area generally better?

Hmm well just double checked FI's site and for my size box the max port area they recommend is 36" so I may be redesigning AGAIN, lol

[bubbagumper6]

Well...how about this?

26D x 17W x 15H
Gross: 2.9668
Net: 2.41795
Port: 15.5 x 2 = 31 square inches
Port Length = ~24.75 (I'm rounding the numbers up so the tuning goes on the lower side to account for any bracing I do)

[spl_robb]

keep us updated on how the box performed

[bubbagumper6]

Yeah no prob, just started building it today. Will get pics up later

[bubbagumper6]

Created a build log to keep track of all my stuff

http://www.caraudio.com/forum/showthread.php?t=416555