If a subwoofer required 2 4in diameter 9.9in long port holes and i wanted to use 3 3in diameter port holes would this be posible? How long would they have to be and would it produce the same output. Im asking beacuse I have about 4ft of 3in diameter PVC pipe. Thanx
9.25 inches long...(for the 3 inch ports) it's close but the two 4" ports are more practical... with the two 4" it is 25.12 cu.in. of port area whilst the 3 3" ports have an area of only 21.195 cu.in. (more is always better in my opinion when it comes to "port area" that is. (4) 3" ports will work better because it yields 28.26 cu.in. of port area. 10-1/2" long for the 4 3" ports... hope this helps... "watch out for port noise! make sure u have flares at the ends."