The present software allows the conversion of a standard audio signal to MIDI signal with an insignificant delay. The software converts also MP3-files, WAV-files (including ACM-compressed) and CDA-files (CD Audio Tracks). The resulting MIDI signal can be given to a standard MIDI device, PC speaker, built-in sequencer. The resulting MIDI events (notes) can be stored as a MIDI-file.The audio signal spectrum is displayed in a special window in real time. The signal spectrum representation allows the software usage for the comfortable guitar tuning.