As an owner of a traps drum set, I know the frustration of trying to get the bass drum tuned. Here's something that made a significant difference. This is the first thing you should do before tuning or going out to buy new heads.

I positioned the kick making sure it did not touch the floor. In my case, it was carpeting. A notable difference all of a sudden in the low end. If you feel the sides of the kick as you hit it, there's alot of vibration emitting from the bass "shell". By seperating it from the floor, it does not get dampened. This also means that the kick pedal will need to be elevated too, but something as simple as a couple of pieces of cardboard underneath would work. Even better would be to find a way not to clamp the pedal at all to the kick.

d4H