I agree, except my box was built by a friend for me and even tho he said said it was 36hz i think it was 38hz when i tried to calculate it and it was built like crap air was escaping everywhere. I had to remove the box i tested the sub in which I built which was 3.0 cubes and tuned to 35 hz. it sounded better but just didn't fit in my car how I wanted. Bj fisher is building my new one.you're not gonna gain anything by tuning 1hz lower (assuming your last box really was tuned to 36hz).
you should aim for a ~5hz reduction if you want something decently noticible.
