i tried searching but came up with 1000's of results. I am wondering how to measure port length in a slot port box? If i do not have any 45 degree angles on the port walls do i just measure the distance from all the walls of the ports? Like my box is 13.5" deep internally with a 3.5" port width. I have 2 10" port walls and a 3.5" port wall totalling 3 port walls. is my port length 41". also on the flip side, if i added 45 degree angles to all port walls then where do i measure then? i wish i had a picture of a slot port box to better explain myself.