If you like intense, deep bass, it is very important to get a good subwoofer. They are fine if you are watching Jane Austin stories using a 70 watt mass market receiver, small satellite speakers, the subwoofer, and Pro Logic. Spend at least as much for your subwoofer as you do for the receiver or outboard power amplifier. That bang you hear is the subwoofer amplifier clipping no doubt. The only way around this is to turn the volume down on the LFE channel in relation to the other channels.
Every movie has a different amount of low frequency signal in the sound track.
It all depends on what the director wanted to achieve. That way, even if the bass is not quite as loud as I would like it, the bass that is there, is clean. You can also put the subwoofer in a corner, which will increase the bass output to the room. Even so, don't turn the subwoofer volume up too high. You should not be distracted from the movie by the bass.