# Sound difference between musical instruments [duplicate]

I know that the difference between two musical notes is given by the sound frequency, and the difference in volume is given by the amplitude.

What I am wondering is why does the same note sound different on different musical instruments? What in the wave makes the difference between the sound of a harmonica and the sound of a violin singing the same note?

To be more concrete (and keeping to a slightly simplified view), you play the A note (440 Hz) and then you have the harmonic frequencies 880, 1320, 1760, ... ($440n$ where $n$ is the number of the harmonic). Each of the frequencies will have an amplitude or "volume" contributing to the sound produced by an instrument. Thus a particular set of amplitudes gives the instrument its tonality.