Porting box with multiple ports?

[Dunerider5 10+ year member]

I have 2 infinity kappa 12's in a sealed enclosure, about 3.1 cubes (not seperated). I want to port this box, but I dont have the tools to make a good hole thats like 4 inches in diameter. Can I do something like (4) 1 inch diameter ports, or 2 inch diameter ports? How do I know how long they have to be? Im hoping to tune to about 35hz.

Im doing this because I want to know how the ported box sounds, so when I build my new box for my new vehicle, i can decide between ported and sealed.

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[bcarpenterfhl 10+ year member]

ported boxes also have to be bigger that your reccomended sealed box to sound good. and for 1 inch tubes does not equal the area of one 4 inch tube.

 

[Dunerider5 10+ year member]

I realize that, Im just wondering if I could do more smaller ports, so I can cut the hole with a hole saw. Im also wondering how to know how long each port has to be, when doing more than one port.

 

[joeldirt 10+ year member]

I have 2 infinity kappa 12's in a sealed enclosure, about 3.1 cubes (not seperated). I want to port this box, but I dont have the tools to make a good hole thats like 4 inches in diameter. Can I do something like (4) 1 inch diameter ports, or 2 inch diameter ports? How do I know how long they have to be? Im hoping to tune to about 35hz.
Im doing this because I want to know how the ported box sounds, so when I build my new box for my new vehicle, i can decide between ported and sealed.

YOu know those Kappa 12's sound great in a sealed box. Not bad in a ported box, but they perform best in a sealed box. If you are looking for a different sound porting the box isnt a bad idea, but making 1" or 2" ports is however. there is a similar thread I jsut posted in about ports. Too little port area will give you a substantial amount of port noise which you dont really want. But.... if you do want to port your box as an experiment, you will have to do some planning and brain storming firts to see if it is possible. Is your box's dimensions big enough to allow for the length of port required?

use this calculator to help:

http://www.audiobahninc.com/tech/Calculators/PortLengthCalc.htm

 

[Dunerider5 10+ year member]

Wow, according to that calculator using 2 ports of the same diameter requires the ports to be alot longer than if you just used one. I guess it would still be helpful though, because there will be less port noise with more ports.

Hmm, 4 ports, 2 inches in diameter, 10 inches long, tuned to 30 hertz. Maybe that would work.

Thanks for the link.

 

[theCybe 5,000+ posts]

It would seem to me like more, smaller ports would equal more port noise.

 

[joeldirt 10+ year member]

Wow, according to that calculator using 2 ports of the same diameter requires the ports to be alot longer than if you just used one. I guess it would still be helpful though, because there will be less port noise with more ports.
Hmm, 4 ports, 2 inches in diameter, 10 inches long, tuned to 30 hertz. Maybe that would work.

Thanks for the link.

Good initiative, but go ahead ant try it, and it will prove to be bad judgement. The theory you ahve just came up with may seem like it will work. But actually you will still experience more port noise then if you were to use one large one. I would use one large one.

for 30hz., I would use a 4" port @ 9 1/4" long...................Actually I would build a whole other box, but I understand what you are doing, so this is what I would do. This is jsut to give you an idea of the difference. So you are planning on tossing this box any way. If you need help on alternative ways of cutting out your hole, let me know and I cna give you some methods to cut out your hole.