Hi

I would like to know if NAudio can read MIDI, and if it's possible read the values of each frequency (value of each signal) of this file

NAudio has classes to read MIDI events from standard MIDI files. MIDI events do not contain frequency information, but you can get the Note numbers from the Note On events.

Ok, and the read of MIDI file is like a WAV or MP3 file ?? or is most complex ... Do iu have examples about it ???

There is a MidiFileReader class you can use. MidiFileMapper is an example of an application that uses it. You should probably also do some reading up on the difference between WAV and MIDI files, as they are very different.