Quote: "How hard is it to make 7hz? Seems odd that if sounds can destroy so easily, they aren't already being used more "
It's pretty easy to get any frequency of sound (except really high frequencies like 1 GHz and over), however the intensity of the sound - basically how loud it is, needs to be very high. This means that a lot of energy is needed to blow something up that it becomes impracticle to use it as a weapon.
Also the rate at which sound dissipates due to air is inversly proportion to the square distance from the sound, which means even if you had a high intensity sound (say large enough to kill you at the right frequency), within 25 - 75 metres the sounds intensity wouldn't be large enough to kill you any more.
@ El_Goorf
Your oscilloscope must have been connected up to some pretty loud and good quality speakers to feel (as you can't hear it - its below our hearing range) the brown noise, because you need a large intensity level for the sound to be effective and most speakers don't go below 20 Hz (generally), as we can't hear it.
pizzaman
