Question

Do you know the name of a tool to do some tones from a set of examples, I recently heard it created a great classical song like Bach’s.

Answer 1

There has been at least one neural network attempt where the input for the network is music samples, and the output is also music samples. Therefore if the network is trained on Bach, it will output Bach-sounding music. You may be more specifically referring to the Harmonisation of Bach chorales paper:

This project is an attempt to produce intelligent machine harmonisation of
chorales. The goal is to harmonise melodies in the style of J.S.Bach; we wish to
nd tendencies and perhaps rules that Bach may have followed consciously or
unconsciously.
We have chosen a GA approach to construct the new harmonisations. We
discuss the use of rule-based evaluation and proceed to make experiments that
are based on neural net tness evaluation after training on a set of Bach chorales