A question maybe for the serious DIY’ers or engineers. (A bit of a story but any help and I'ld be chuffed) I have just started my final year for my degree in engineering here in Ireland. As a final year project, I was hoping to make a injection mould for a extendable flared port for a subwoofer. This was ok as a project but I had to give a reason for making it variable length. I was thinking that the port could be set at its proper length ( 11” for my tempest sub) and then could be varied a small bit to suit a room (like furniture, placement and size of room could interfere with actual output of the sub, I am not sure if changing the length would do much difference though?). I was hoping if some of ye people could answer this question for me. Could some one point to a website where it shows the difference in varying the length of a port. I have downloaded one or 2 sub design programs, but are abit too complex, a simplier one would be handy. It could even turn into a project about the angle and size of the flares at the ends, where I would have to research all shapes/sizes of flares and make the best one that can increase the sound and decrease the chance of air noise. Any other kind of ideas would be helpful iswell. I want to do something in this line but no one really knows what I am talking about in college. Any help would be appreciated.