For a while I've noticed a very large crack sound when I do a drop larger then a curb (more so on dirt) on my bike, a K2 Attack with a 150mm fork (my main concern at this point), that would be taller then twice the height of a curb or so. It's bothered me a lot since the sound is deafening but nothing has broken, bent, or has shown signs of damage. The best way I can describe it is that if you did one drop and heard it, you would be frantic trying to find what broke, your first thought being the frame.
I've read that on hollow aluminum frames, the chain slap can get extremely loud if the stay is not covered. However, the chainstay on this frame is quite small and not really connected to another part of the frame where the sound could resonate.
Anyone else had some sort of really loud sound crack? I'll try and get some sort of recording of it tomorrow if it'll help.
Edit: I'm prompted to ask now because on a ride yesterday, we rode up singletrack and down this "unimproved forest rode" that is nothing but rock a bit bigger then gravel. Not a rock garden by any means, but the type of thing you can ride over easily but by the time you get to the bottom your hands are either in agony or you cant feel them at all. Point being, the whole time this noise wouldn't stop. So it's not just drops, but rapid bumps as well.