how much port area?

[I want SExxx 10+ year member]

Port the hell out of it..... I got 2 sexxx 12's in 4.5-4.7 cubes NET w/ 66 sqin of port area.... only b/c Ihave a small *** mustang trunk..... 40 should be nice..........

p.s. I like 28hz tuning better then 32

 

[jellyfish420 10+ year member]

Port the hell out of it..... I got 2 sexxx 12's in 4.5-4.7 cubes NET w/ 66 sqin of port area.... only b/c Ihave a small *** mustang trunk..... 40 should be nice..........
p.s. I like 28hz tuning better then 32

ya but the lower he tunes and the bigger area the smaller the inside of the box gets...

 

[tommyk90 5,000+ posts]

Ok, i'm doing 40 sq. in. for the 12" XXX

Now i have ANOTHER box, for a 15" Brahma.

I'm kinda low on space for this one, and 30 sq. in. is about all i can muster right now. Should i go more if possible?

 

[jellyfish420 10+ year member]

Ok, i'm doing 40 sq. in. for the 12" XXX
Now i have ANOTHER box, for a 15" Brahma.

I'm kinda low on space for this one, and 30 sq. in. is about all i can muster right now. Should i go more if possible?

so your gonna give the 12 more port area than the 15???

 

[squeak9798 5,000+ posts]

http://www.diysubwoofers.org/portcal.htm

Minimum Port Diameter

To calculate the minimum diameter of the port required to prevent port noises, you will also need to know the following:

Xmax = maximum linear displacement (mm)

Dia = Effective diameter of driver (cm)

Np = number of ports

Calculate the minimum port diameter from the following equations:

Sd = pi*(Dia/100)^2/4

Vd = Sd*Xmax/1000

Dmin = 100*(20.3*(Vd^2/Fb)^0.25)/Np^.5

where,

Dmin = minimum port diameter (cm)

 

[tommyk90 5,000+ posts]

so your gonna give the 12 more port area than the 15???

I know it's stupid, but i have less room for the 15" box then i do the 12" box, which makes even less sense. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[DBfan187 5,000+ posts]

Go sealed then. Brahma's can reach full potential in small sealed enclosures with only 900watts.

 

[tommyk90 5,000+ posts]

Go sealed then. Brahma's can reach full potential in small sealed enclosures with only 900watts.

Well, i'm building to this guys specs. He wants 4.18 cubes tuned to 28 hz, so i'm trying to make it happen.

BTW, that calculation is a bit too much for me. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I'm not exactly sure how to tackle it. If someone else more mathematically inclined can go through it i'd appreciate it. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jellyfish420 10+ year member]

4.18 cubes before or after displacements? if its before displacements its only gonna

be like 2 somthin cubes net. but if its after do you realize its gonna be like a total of 7 cubes? whats your max dimentions???

 

[tommyk90 5,000+ posts]

4.18 cubes before or after displacements? if its before displacements its only gonnabe like 2 somthin cubes net. but if its after do you realize its gonna be like a total of 7 cubes? whats your max dimentions???

After displacement.

And i'm not sure on the dimensions yet though because the "max" ones he gave me to start off with i cant even get enough air space with, so i asked if he can go bigger.