> The new calculation indicates that for ordinary sound waves in most materials, the mass carried is equal to the sound wave energy multiplied by a factor that

> The new calculation indicates that for ordinary sound waves in most materials, the mass carried is equal to the sound wave energy multiplied by a factor that depends on the speed of sound and the medium’s mass density. Since the effect is proportional to the density of the medium, you can't get actual antigravity. The mass is always positive. It can just be lighter than the other matter around it. Practically speaking, you definitely can't use this for levitation or anything. This is E=mc^2 stuff; you need far more energy than conventional levitation would take. The energy in normal sound waves is very low, so high energy sound waves are very destructive. For reference, the reference level sound intensity is 1 picowatt per square meter. That's zero decibels, the human audible threshold or the quietest sound we can hear under ideal conditions. A conversation is ~60 decibels, or 1 microwatt/m^2. Hearing damage comes at >90 dB or 1 milliwatt/m^2. >140 dB is quite painful, but it's only 100 watts/m^2. A household extension cord can carry about a kilowatt in less than a square centimeter- millions of times more power.