check my design

[king ranch 5,000+ posts]

so i am trying to make my own box for 2 12's l7's ported

i used re audio box calculator

heres what i came up with

box width 35

box height 17

bottom depth 21

top depth 21

wood is .75

port width 4inches

port length 2 is zero

port lenght 1 is 16.25" but it says the total port length is 23" why does it say that

leaves around 5cuft net and at a 33hz tune will this work

also is the ox volume net and when adding up the net do you add the port displacement in with net or does it get used as taking up space

Click to read more...

 

[BrianChia 10+ year member]

yes.

 

[king ranch 5,000+ posts]

yes to what it will work

also why does it say the total port length is 23" when it shows it being only 16.25

also with port displacement it should be right around 5cuft net correct

do you add the port displacment for net or do you subtract the port displacement from the voulme of the box

wats the formula for figuring out how much port displacement is

 

[miker 5,000+ posts]

port area time length?

 

[king ranch 5,000+ posts]

huh

 

[miker 5,000+ posts]

width of port * height of port * length of port

Then do the same for the MDF you used to build the port, or just incorperate it into the port dimensions.

 

[king ranch 5,000+ posts]

ok so 4x15.5x15.5 corret if thats true that gives me 961 but how do i figure out how much it displaces

 

[dman4486 5,000+ posts]

ok so 4x15.5x15.5 corret if thats true that gives me 961 but how do i figure out how much it displaces

that is cubic inches...that is displacement

 

[miker 5,000+ posts]

that would be 961in cubed.

Divide that number by 1728 (in cubed in a cubic foot).

 

[king ranch 5,000+ posts]

so 961 divide that by 1728 gives me .55 thats how much it displaces or what

so is 5net enough for 2 12's l7's

 

[miker 5,000+ posts]

Yup..

and, not a clue.

 

[SPY 5,000+ posts]

The RE box calc takes the port displacement out of the box volume, all you need to subtract is the sub displacement.

 

[king ranch 5,000+ posts]

how much displacement does a 12" l7 displace cant be more than .20 for 2 subs

 

[miker 5,000+ posts]

The RE box calc takes the port displacement out of the box volume, all you need to subtract is the sub displacement.

didn't notice he was using RE.. lol

 

[miker 5,000+ posts]

how much displacement does a 12" l7 displace cant be more than .20 for 2 subs

pretty sure AVERAGE displacement for a 12" woofer is .07