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View Full Version : port area for a 07 RE XXX 15

406er
01-02-2008, 01:30 PM
as the title states, how much cross section port area for a XXX 15

SeanDub
01-02-2008, 01:32 PM
Depends on cubic feet of the box. It's usually like 16 sq inches of port per cubic foot. 15s that are ported usually have about 4 cubes, so around 60 - 70 sq inches.

Immacomputer
01-02-2008, 01:35 PM
Depends on cubic feet of the box. It's usually like 16 sq inches of port per cubic foot. 15s that are ported usually have about 4 cubes, so around 60 - 70 sq inches.

That's the DD generalization method. The sub plays a HUGE role in determining port area. With my single 12" sub, I can get slight port noise in a 3 cubic foot enclosure with 25in^2 of port area but I don't with two 8s in it. Why? Motor strength, suspension, power handling, excursion, and cone area all play a part as well as enclosure volume. It's NOT just enclosure volume. If that's the case, I'm going to have terrible port noise from my 5ft^3 enclosure with only 36in^2 of port area!

SeanDub
01-02-2008, 01:42 PM
That's the DD generalization method. The sub plays a HUGE role in determining port area. With my single 12" sub, I can get slight port noise in a 3 cubic foot enclosure with 25in^2 of port area but I don't with two 8s in it. Why? Motor strength, suspension, power handling, excursion, and cone area all play a part as well as enclosure volume. It's NOT just enclosure volume. If that's the case, I'm going to have terrible port noise from my 5ft^3 enclosure with only 36in^2 of port area!

Then educate us on how to use sub specs to determine proper sub enclosures. I'd like to build better suited boxes, and was looking for this information last night.

MemphisCherokee
01-02-2008, 01:51 PM
lots and lots

..no really, 16 square inches per cubic feet

bonesninja
01-02-2008, 04:59 PM
i just use this generic calculator.......it seems to jive pretty close with some others i've used. the biggest factor it uses, i believe, is the xmax.

i just used the re optimal specs of 4^3@33 htz

http://i198.photobucket.com/albums/aa108/bonesninja/07XXX.jpg

bonesninja
01-02-2008, 05:02 PM
thats an awful lot of port tho.....due to that insane 54 mm of Xmax

Immacomputer
01-02-2008, 05:36 PM
You don't have to worry about that much excursion because it will be **** near impossible to drive the sub to full excursion around tuning, which is where port noise really becomes a problem. If the sub has low motor strength, you can cut back on port area even more. Drivers with high power handling, moderate excursion, and a strong motor will need more port area.

185in^2 is way too much for a 15" XXX.

bonesninja
01-02-2008, 05:40 PM
You don't have to worry about that much excursion because it will be **** near impossible to drive the sub to full excursion around tuning, which is where port noise really becomes a problem. If the sub has low motor strength, you can cut back on port area even more. Drivers with high power handling, moderate excursion, and a strong motor will need more port area.

185in^2 is way too much for a 15" XXX.

i was thinking that a ton of port area.....the fart box i built for whiteice's 18" mt had 200^2. i'd still put 80"-100" on the XXX tho.

90accordman
01-02-2008, 05:41 PM
between 75-80 is what my 15 XXX had and it sounded great

bonesninja
01-02-2008, 05:42 PM
between 75-80 is what my 15 XXX had and it sounded great

sell me that 10" now...

406er
01-02-2008, 07:32 PM
between 75-80 is what my 15 XXX had and it sounded great

what year of XXX did u have. i think ill aim for 80-100, cause the 168 thats called for is retarded

bonesninja
01-02-2008, 07:34 PM
i think he was one of the first guys here to have the newer style like you have

406er
01-02-2008, 08:26 PM
ahhh