port tuning question

[brokeitagain 10+ year member]

what i wanted to know is how to figure a port that does L off into the chambers on both sides,whit no divider

 

[RAM_Designs 5,000+ posts]

this enclosure does not have the divider in the port

are you seriously still confused??? Both subs share the port, like in this box:

As I said before, there's no secret to this. You can use one port for 1000 subs...the number of subs does not matter.

 

[mobeious 10+ year member]

the length of the port goes both ways

 

[RAM_Designs 5,000+ posts]

what i wanted to know is how to figure a port that does L off into the chambers on both sides,whit no divider

The part that branches off into each side will be one half the width of the original port. An easy way to think of it is "however long you would need to go past the back of the box, that's how far, from the center of the original port, that you need to branch off into each side."

 

[brokeitagain 10+ year member]

******* **** is everybody blind cant u look at the pic i posted and see how the port is in there?

 

[brokeitagain 10+ year member]

what about the volume of the box ?

is it one box or two?

 

[RAM_Designs 5,000+ posts]

what about the volume of the box ?is it one box or two?

Since air can flow easily from one side to the other, it'd be one box, shared chamber.

 

[RAM_Designs 5,000+ posts]

******* **** is everybody blind cant u look at the pic i posted and see how the port is in there?

The part that branches off into each side will be one half the width of the original port. An easy way to think of it is "however long you would need to go past the back of the box, that's how far, from the center of the original port, that you need to branch off into each side."

now stfu.

 

[mobeious 10+ year member]

here this should explain it this is if ur port board had to be 17.75 long, this is how u do it

 

[theo740IL 10+ year member]

you just want the math formula to figure it out yourself right? i was looking for the same thing a while back and couldn't find nothing!!! i kept finding all those different calculators (re audio calc, the subwoofer tools one, winisd, etc) but then i read a bunch of things in these forums and other places that those calculators aren't that accurate. so good look man i looked for a while!

 

[jmrunz 10+ year member]

brokeitagain. dont get discourraged people just tell you what they know. with that here is what i know.

when you build a box for 2 subs shared space the volume needs to be big enough for both subs. say each sub requires 2 cubes then you need a 4 cub net box. keep in mind that that is after port and sub displacement. you can easuly end up with a 5.5 cube box to get 4 cubes net.

a rull of thumb we use is 16 inches squared per cubic foot of box volume. when you run a divider in the center of the port dividing the chambers up the playable area comes back into each chamber a bit.

port tuning is dependand on surface area and depth of port. the smaller the surface area the higher port noise you have. if you go to ddaudio.com and use their calculator it works real good but you want to figure it out yourself i have a couple of formulas and web sites you can visit to get these for yourself and i hope they help you as they have helped me a ton.

here they are.

http://www.realmofexcursion.com/forum/showpost.php?p=447126&postcount=1.

http://www.caraudio911.com/tutorials/PortedBox/images/001.gif

http://www.usenclosure.com/Enclosure%20Formula's/enclosure_formula.htm

and here are some difinations of abreviations

.Lv = port length (what your solving for)

Av = your port area (height x width of the port face)

Vb = the internal volume of your box

Fb = the tuning frequency you want

again i hope these pages and info helps you in what you want.

james