How big is your box right now, if you made the port longer and it did not change the note the box might be too small. Before we can tell him to make his box bigger or smaller we need to know how big it is right now. Which way do subs face which way do ports face? To many variables......like Tom said you need to only change 1 thing at time and test.

 

if your not too sure then shut up . a.k.a. paul bunyan.lmao

 

the box is 16"tallx29.25"widex25.5" in depth the sub faces up and the port is to the rear of the van and yes mat the box is 7 cu ft and the port is 140 square
inches thanks for the help guys

 

If those are external measurements and you used .75" MDF your box is 5.58 cubes not 7, and this is before sub and port displacement, I bet that the actual NET volume is closer to 4.5 cubes. Which is not bad for one 15" sub. How deep is your port?

 

ya, those are external dimension's. inside is about 5.6 cuft, including the vent. I think maybe making it 7cuft internal "including the existing vent area would be better suited and bring that tuning freq back to earth, what ya think?

 

i re measured the box today to be positive i gave you the the right measurements and i was off a bit lol internal the box is 28 wide x 24.5 deep x 14.25 tall and the port is 5" tall x 28" wide and the port wall is 14" deep the box

 

maybe i shoulda got to "johnW's" post before i added my two bit's worth lol

 

hi tim!!!!!!!!!!

 

i just did a re check on the measurements barty and it works out to 5.70 before
sub and port we were a bit off on that one lol