I am not expert in music.
There are number of [musical instruments][1]. One (especially a person who knows about music) can blindly recognize which instrument is being played just by listening to it. 


**I need mathematical explanation about following**

>Every instrument (say Guitar, Harmonium , Violin like that) seems to be unique while listening. My basic question is why is it so?
Why different musical notes sound different on different instruments ? 






  [1]: http://en.wikipedia.org/wiki/List_of_musical_instruments