Determining port area

[herbykw]

I'm building a box for Four DC lvl 2 8"s. The box design is 3.46 cubes. How do i determine how much port area is right for a single 8"? It was recommended to use two 6" ports. Using two 6" ports they have to be 31" long to tune it to apron 35 hertz. That ports the port area at 17531 cubic inches. Is this too much?

[77-AUDIO]

Need more than just the cubes to get that. IIRC my old box with my 4 - DC 8" was 34"x14"x18" before port. And I had a 3" wide slot port 12.5" tall tuned to 33htz and it got down and dirty. 141.9 on music with a SAZ-1500D.

your 2 - 6" ports are 56.54 inches of port / 3.46 = 16.3" of port per cube. some say thats fine but I like about 12" of port per cube. mine was close to 12" of port per cube.

have you tried to use the torres box calc. once you figure it out its really simple. I have spoken to rusty regarding those subs and he said keep them in about .8 cubes net. Im actually going back with 2 - 8" DC in a box thats about 2cubes before bracing and 45's. so I will be around .9 cubes.

[cjvue]

Two 6" port is too much for that box. If anything, i would do one 6" instead.

[herbykw]

Need more than just the cubes to get that. IIRC my old box with my 4 - DC 8" was 34"x14"x18" before port. And I had a 3" wide slot port 12.5" tall tuned to 33htz and it got down and dirty. 141.9 on music with a SAZ-1500D.

your 2 - 6" ports are 56.54 inches of port / 3.46 = 16.3" of port per cube. some say thats fine but I like about 12" of port per cube. mine was close to 12" of port per cube.

have you tried to use the torres box calc. once you figure it out its really simple. I have spoken to rusty regarding those subs and he said keep them in about .8 cubes net. Im actually going back with 2 - 8" DC in a box thats about 2cubes before bracing and 45's. so I will be around .9 cubes.

Thanks, how did you determine this? I have used torres calc, but that doesnt help with what im asking, unless im just missing it.

Two 6" port is too much for that box. If anything, i would do one 6" instead.

ok, why? how do you determine that?

[77-AUDIO]

I used Autocad. I drew a 6" circle and then did did a properties of it and it gives me the area. and then I multiplied it by 2 for two ports and then divided it by your box volume. odd information about circles. whenever you double the size of a circle say 2" dia to a 4" dia you have 4 times the area.

So 1 - 4" circle is the same as 4 - 2" circles

Area of a 2" circle is 3.1416

Area of a 4" circle is 12.5664

[herbykw]

Bump.. Anyone know how to determine how much port area to use?

[herbykw]

Bump

[RAM_Designs]

If using an aeroport, a single 6" port is fine. Go with more port area and you're looking at having to mod your ports. Are you totally against using a slot port?

[herbykw]

If using an aeroport, a single 6" port is fine. Go with more port area and you're looking at having to mod your ports. Are you totally against using a slot port?

IM not against using slot ports at all. If i use slot ports the same question is there. How do i know how much is enough, but not too much port area? I dont want someone to tell me how much to use, i want to know how to determine it myself, for future builds.

[BCarter]

Read the vance dickason port method, and you will have a greatly tuned enclosure.