@kartikoli: I don't think that's going to work. I'm assuming you removed noise by selecting a noise sample and filtering it from the audio. But separating two instruments in an audio stream is going to be a different work altogether. I've removed the zzzzzzz noise from audio using Goldwave but could never manage to separate two instruments (I have tried this with Goldwave and Audacity).
In fact (in my experience) even the noise filtration is not perfect and leaves 'tinny' sounds.
@OP, probably you'd be better off searching for two different audio files; someone playing the same audio solely on a piano and another one playing it solely on the violin. People who play instruments for hobby often do that.