I got a 12" dvc rockfod stage 3... and am getting a seald box rockford recomends a .85 cu ft and thats what im getting but should i still put pollly fill in it cuze its slaned back so the sound waves shouldnt heat up the voice coil too much but i thought you were only supposed to use polly fill if you box was too small maby i am wrong... any help would be grate... almost done with my system