Like at the electromagnetic waves we see that they interfers the way like two different wave with frequencies can exist in the same place.
Why quantum superposition? An electromagnetic wave (in vacuum of in a medium) can be thought of as a classical wave and so does a sound wave (through air or any other medium).
Any wave obeys superposition at the classical level! Since the wave equation is linear, a superposition of two propagating waves is also a solution of the wave equation. And superposition can give rise to a whole host of phenomena. For example, when two sound waves (or the electric fields of an electromagnetic wave) of same frequency and constant phase difference are superposed, it gives rise to the phenomenon of interference while the superposition of two sound waves of slightly different frequencies lead to beats.