Rules for port diameter?

[JonJT 10+ year member]

Does anyone know the general rule of thumb when determining the port diameter you'll need? I'm making a ported sub with 2 Koda 8s and I don't know if a single 4 inch flared port will cut it.

The 2 kodas can displace about 1444 CCs of air at maximum. (I used Xmech in that calculation)

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[flakko 5,000+ posts]

last time i checked it was 8:1

 

[DBfan187 5,000+ posts]

last time i checked it was 1:8

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[JonJT 10+ year member]

last time i checked it was 8:1

Units? you mean 1 unit of length of the port for every 8 units of volume of the box?

 

[DBfan187 5,000+ posts]

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

 

[chozen1 10+ year member]

i use the 1:6 ratio

 

[tRiGgEr 5,000+ posts]

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

Remember the dimmensions it supplies are optimal. You can get away with less port surface area in the proper box.

 

[JonJT 10+ year member]

Ok, then 6.5 inches it is. Thanks.

 

[tRiGgEr 5,000+ posts]

Ok, then 6.5 inches it is. Thanks.

Good luck finding a 6.5" circle port. Use two 4" ports and you will get 25.12. Plaenty of port surface area for two Kodas.

 

[DFW40 10+ year member]

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

Whatever this site gives you just cut it in half or so. It is not necessary to have 48 inches or port area for a 12 inch Brahma unless you are tuning around 55hz for spl comps.

 

[JonJT 10+ year member]

2 4 inch ports make for about 19 inches or port length, I hope WinISD isn't getting this wrong.

 

[DBfan187 5,000+ posts]

a bigger port will increase enclosure efficiency.

2 of these then use this calculator.

 

[djman37 5,000+ posts]

Good luck finding a 6.5" circle port. Use two 4" ports and you will get 25.12. Plaenty of port surface area for two Kodas.

i know where to get 6" aeros.//content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif

 

[bimma85 5,000+ posts]

a bigger port will increase enclosure efficiency.

2 of these then use this calculator.

Say you have 4 ports. Does each port have to be that long, or does the length of all 4 ports need to equal the total length they give?

 

[DBfan187 5,000+ posts]

each.