I have a box that is tuned to 45hz *yeah, I know that's pretty high, but it was built for me by the audio shop I bought the sub from*, anyway, the box is about 3 ft^3 net. how much polyfill would it take to drop the tune to about 36hz or so. or would it be better to build a different box.
I don't think that polyfill will change the tuned freq. of a box man, or at least I have never heard of it working before. I think you're going to have to build a new box if you want to drop the freq, or just mess around with the port.
its better to build a better box to a desired frequency. i would only recommend polyfill to drop it a minimal amount from a range of desired tuning, although i am a begginer to, so u shouldnt take my word for it i guess
ok heres the deal to move your box tune down youd have to add three inches fiberglass insulation or three pounds polyfill for a 39.5 hz tune i wouldnt suggest going any more with the insulation that this if you have enough room in the box to do this and to keep port volocity on the borderline using a 4 inch pvc port youd have to apply no more than 225 rms watts....if you want to change your tune lower you would have to put a new port in and go wider than your port diameter