6 re 8's. box plans

[req 5,000+ posts]

ok here is my delima mr c.

is it just trial and error until i get 37hz?

do i have to sit there and guess dimensions until the tuning comes out right? how does that work? this is what noone is clearing up for me. i dont want you to just give the awnser of the dimensions. but just tell me how to freaking do it =\

ive found absolutly no information about slot ports that everyone seems to have. nor fiberglass boxes with these ports, but i see them in pictures all over.

whats the deal?

//edit

quoted from the site you just posted;

"Port Length Calculator

To calculate the port length of a round port, enter the diameter of the port"

now how does this help me?

but with a 17.7" round 4" port i get 37hz. //content.invisioncic.com/y282845/emoticons/chicken.gif.218ea7401db50d5e31a7e0b37e05e21e.gif

 

[supa_c 5,000+ posts]

1. yep, you have to fiddle around with the dimensions.

2. slot port calculators are non existant unless you have a program that does it.

3. if you know the round length/diameter it helps to find the slot, i think ?

 

[req 5,000+ posts]

alrighty then. i found a site that does square port sizes, but i didnt realize why it didnt work when i last saw it. it had height\width boxes on the right that i missed.

@1.2cuft @37hz this site came up with (i had to fiddle around with it like you said to get it a resonable length);

8"wide

2"tall

18.85"long

that equals = 0.09545 cubic feet of port area (regarding the site you posted on the internal volume calculator)

so that is 164.9376 cubic inches?

does this sound horribly wrong?

 

[supa_c 5,000+ posts]

horribly, horribly wrong.

whats that site, if you dont mind

 

[req 5,000+ posts]

http://www.carstereo.com/help2/Articles.cfm?id=31

 

[supa_c 5,000+ posts]

beats me.

just ask Jmac

 

[req 5,000+ posts]

Where Av is the cross-sectional area of the port (in square inches),

Lv is the length of the port (in inches)

and Vb is the enlcosure's net volume (in cubic inches).

*courtisy of JL audio

that one is supposed to give me the port length? "Fb"?

could you jsut explain to me what all that crap means? what is Fb = .159?

and where do i get the length of the port. and i have the volume from the round port calculator- i should use this- correct? (0.12872 cuft)

to figure out sqin its (insert cuft #) divided 1728.... in my case its 7.449... right?

 

[supa_c 5,000+ posts]

Fb is th tuning frequency

if you can do that equasion you have me beat, because i have no clue how to do it

 

[req 5,000+ posts]

ok here we go.

i can do this thing, but i still dont know where the hell i get the length of the port. or the width or the height. needless to say what the hell a "cross sectional area" is.

wtf does that crap mean?

 

[supa_c 5,000+ posts]

*edit

cross section is the port cut in half diagionally.

 

[req 5,000+ posts]

ok, now awnser me this.

HOW ON EARTH am i suppose to get that god **** number when ive got NO FREAKING CLUE the height length OR width!?!

AHHH WAHT THE HELL IS WRONG WITH THIS PICTURE?!

 

[supa_c 5,000+ posts]

i asked Jmac to help, hopefully he gives you some insight on how to figure this out

 

[Acidburn 5,000+ posts]

there is no set number for the area of the port, some people use the 12 square inches per cubic foot method, some just make it as large as possible since the bigger it is, the more SPL

put in the volume of the box you need and the frequency you want it to be tuned to

then use one of the above methods for area of port and bingo, out pops the length of part you need

 

[req 5,000+ posts]

ok screw that.

i played with the12volt.com's internal volume calculator until i got close to the port calculators results and came up with this;

height = 2.2

width = 10.2

depth = 17

cuft = 0.12886 (the round port calculator came up with 0.12872 cuft for 37hz internal volume)

does this sound right? thats really close to the origional... //content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif

 

[supa_c 5,000+ posts]

you make it sound so easy.

but to n00bs its not