Hey, I'm about to start building my first box and could use a little help with the specs. This box is for a 15" Kicker Solo-Baric L7 and is going to be roughly 4.5 cubic feet, excluding the port. The thing is I am not entirely sure what my port volume should be. I have established that 4" diameter pipe is a good choice, but I'm not sure about the length or total volume. Any help would be appreciated. Thanks.