I just bought a barely used type r 1542 that was in a custom box. The box is huge, 34x22x19 and the slot port is 3x18x18. I figure it's about 6.5 cubes so is this too big for one sub? I have another 15" box that is 21x13x19 slot ported. The bigger box is tuned to about 25-30 hertz and the...