Ok , so I've been working on my diy 2-15 cabinet on and off for a while now and I have a question. The internal dimensions are 35"x23.5"x12" for a net volume of about 5.3 cuft. It has 4 3.75" diameter flared ports that came 7.63" long and it has 2 3015's in it. My calculations came up with a tuning freq of 46.5hz. I did a rice test and the grains never stopped bouncing , but bounced a lot less in the 42hz range. I shortened the ports one at a time by 1/2" each and the rice movement slowed closer to the 47 to 48 hz range. I have tried the cab lined with thin quilt batting as well as 2" thick white fiberglass insulation. I have also tried it with one port blocked and one tube removed , which should greatly lower and raise the tuning freq. Here is the question , it sounds great in the mid and high ranges , but the low notes , especially the open E string , do not sound full and strong. I have to really crank the bass on my SVT-CL or it sounds hollow and mid rangey. Describing tone is difficult , but it does not have much low end. It also sounds the same when I was playing around with the port tuning. Nothing I did changed the tone much at all. Any advice on what tuning frequency to shoot for? It is built from 3/4" 13 ply baltic birch , glued and screwed. Maybe I just don't get along with the tone of the 3015's. My favorite cabinet is an Ampeg 610hlf which some people find too bassy. Thanks for any help.