box for my reconed sub?

[ncc74656]

i have been running a 29hz tuned sp4 18 for a while now and while hte lows are good id like to have better high end response. when my sub poped i put my 15" sub tuned at 35hz in the truck (just a little guy) and i really like how smooth the response is and the wide range that it has. to that end id like to build a simple box to play with a 35hz tune. this is what i came up with and id like to know if im on the right track. i think i want a bit less port area so as to provide more resistance and control of the sub. by the math of 9-12sq per cube i come to about 85 sq in of port for a SP4 18".

[Kyblack76]

In for everyone saying the port area is to low.....

[ncc74656]

my old boxes port area was about 106. what should a SP4 be seeing for port area?

[ncc74656]

i have read that its best to use a port that is as sqare as possible E.G. a port that has a ratio of 1:1 instead of 1:20 and thus i was trying to stay as light on the ratio as possible. if i used the full depth of hte box for the port i would be at a 1:4.4 ratio if i went a bit more port up to 110 squared. thoughts on that?

[Kyblack76]

I dont chime in on peoples enclosures. It just seems like if you dont run 20" of port per cube, its a fail.

I also run SP4's. And where i wont get into my shit,...... i also, am on the "lower" end of the spectrum.

Im sure someone else that plays with torres and T/S poop will gladly chime in.

Good luck bro.

[ncc74656]

my understanding is that port area is an issue when it comes to speed of air exiting the box and port noise. outside of that it comes into play with the total length of port needed for desired tuning and then if you have to large of a port the sub will operate more as an IB than as a ported enclosure and to little port will operate more like a massive sealed box than a ported.

if i run the sub in a ported box with a 120 sq in port then id be looking at about this; which is 18 squared per cubic so its a on the upper edge of the ratio that i have seen commonly referenced: