1. ## need help figuring port demensions

Im gonna be building a box for my Fi 12 BTL b/c my last one didnt fit. It wasnt tall enough and i wasnt thinking about the front being angled too much for the magnet to fit. Plus it was a smaller box. So I designed a new box. im going to put the sub facing the front with triple baffles. I just need help designing the port for this one. Not sure wether to use a round port or a slot port. I wanna tune it to 32 hz. Could somebody help me figure the deminsions for a port. The box according to rockfordfosgates boxwizard the box is going to be 3.3 cu ft before the port and sub displacement. Heres a pic RF calculator i used to figure the area.

And heres a pic of the design from sketchup. I have the sketchup pic saved too if somebody wants to use it to design the port.

2. ## Re: need help figuring port demensions

http://www.carstereo.com/help2/Articles.cfm?id=31
i like this calculator. just do a litle math and it will tell you how long it needs to be. the length is assuming net volume so take that into consideration

3. ## Re: need help figuring port demensions

Originally Posted by germanyt
http://www.carstereo.com/help2/Articles.cfm?id=31
i like this calculator. just do a litle math and it will tell you how long it needs to be. the length is assuming net volume so take that into consideration
yeah...you need to use the calculator once to find the length and then figure out the displacement. subtract the displacement from your original volume and plug the numbers in again to get the length you cut to.

4. ## Re: need help figuring port demensions

ok so if i done my math right (which i prob didnt) then i could use 4 2inch pvc pipe with a length of 9.25 each for a tuning of 32hz. box would be 3.3 b3 and 3 cu ft after port and sub displacement. does that sound right?

5. ## Re: need help figuring port demensions

thats only like 12.5sq" of port you will need a least 36sq"...(i do a minimum of 12sq" per cu'....a lot of guys will tell you to do more but for a single 12 30-36 should be fine.)

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