The theory behind sound is very simple – waves are just added up, so the amplitude of two exactly identical waves is doubled, if one of them is shifted by pi radians they cancel and the amplitude becomes 0, if it’s shifted by less or more then a pattern is created that causes periodic pulses of sound. However, in everyday experience, this is practically nonexistent. If the “valleys” of sound waves subtract from the “peaks” of other sound waves, and if waves spend half of their time in a valley, I’d expect that exactly half of the time sounds would cancel each other, but I’ve literally never experienced anything other than more sounds = higher volume, not even in an orchestra with many people playing the same note. What gives?
In: Physics
>If the “valleys” of sound waves subtract from the “peaks” of other sound waves
* They only effectively cancel if they are both the same frequency, same amplitude, and arrive at your ear at precisely the same instant.
* When sound waves hit a thing, be it a person, a wall, moisture in the air etc, some of them get absorbed and some get reflected, sometimes at a different angle.
* Because of that, it’s very uncommon for sound waves to actually cancel them selves out.
* It does, however, happen in some circumstances usual with very loud sounds in a very symmetric space, like a rectangular building during a concert.
* Audio engineers at live concerts have to be keenly aware of how this cancellation can effect the sound the concert goers hear and make sure they compensate for it (usually with more speakers pointed in specific directions).
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