port area

Hey guys. I've got at tc sounds tc-3000 15" that I've been running in a sealed box. I'm looking to change to a ported one. The specs I have for the sub states 4.2 cubes with a 30" long port with an area of 25 sq inches. That would leave the tuning at 20hz which is really low. That would also leave the port about 15.25*1.64 inches. Does that sound thin to anyone else?

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Pioneer DEH-P980BT, Zapco DCREF1000.4,Pioneer TS-C520PRS, Adire Extremis, MTX TA91002, TC Sounds TC-3000 15"

I've heard that sometimes companies will tell you how much port area per cube instead of how much total. maybe thats why it seems like a thin port to me

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Pioneer DEH-P980BT, Zapco DCREF1000.4,Pioneer TS-C520PRS, Adire Extremis, MTX TA91002, TC Sounds TC-3000 15"

Your example is a ratio of close to 8:1, which is the most extremely narrow slot ratio you should design.  Most extreme, but acceptable.  Better sound, possibly, could be derived if your slot dimensions ran more square...such as 8 X 3 1/8 " or 6 X 4 3/16 ".  But that's not a given.  The quality of the build will have most to do with final results, such as rounding the edges of the slot port on the inside of the box, rounding the edges of the cutout on the backside, flaring the port on the outside (trickier).

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Ok since the box will be around 17" tall if I make the port 8x3 1/16 should I keep it on the opposite end of the box from the sub? In the top corner, bottom corner or in the middle?

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Pioneer DEH-P980BT, Zapco DCREF1000.4,Pioneer TS-C520PRS, Adire Extremis, MTX TA91002, TC Sounds TC-3000 15"