they dont return emails ive emailed them a bunch of times.....i kno someone here has to kno anyone know plz //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif
I used .2 cubic feet for each of my 18s. That was per Chad's advice. So, the 15 is probably .18ish. Thats what I would do. Being off a . of a cubic foot or so isn't going to totally kill your project.