Wasn't there a Mythbusters episode where they tried this, though, unsuccessfully? I think Adam Savage got the dubious honour but was spared a successful experiment.
Are you saying that powerful low frequency sound does not upset a person's stomach?
That would be a myth. The body is mostly water, as you know. It responds to pressure, oddly, due to teh fact that the water is contained in small membranes all touching each other, but it certainly responds.
One of my favorite goofy things to play with, as a younger man, was sub-audible pressures. I once built a resonator type system, with four eighteen inch JBL drivers, that I could use to make people see ghosts. At the resonant frequency of the human eyeball, somewhere around fifteen to eighteen Hz from what I have found, your eyes begin to not function properly. Again they are filled with liquid and making them vibrate causes anomalies in their functioning. I and others could actually see shimmering ghost images of anything moving in our view, but displaced from the original sight by thirty to sixty degrees of view. Some people even got scared and said I was casting a spell with my "electric toys".
Most people can not sense that frequency range in any way. I certainly do.
BTW, it doesn't take very much sound pressure to cause this effect on the eyes. On the order of eighty to ninety dB is plenty. It is the resonance that causes it, not an extreme pressure. I believe that the resonant frequency of a stomach cavity would be a about five octaves below that of an eyeball. A little difficult to produce sound at that frequency, without flame or explosions.
