24-bits ; stereo 44100 Hz This sound is a synthetic one created with the software « Audacity ». At first I generated a tone : 264 Hz corresponding to the music range DO. I duplicated it twice and spaced them. To 0s at 1s ; to 1.5s at 2.5s and to 3s at 4s. It was my first track. My second track had the same process but with the music range SI (495 Hz). I decreased the tracks to -9 dB and used the envelope tool for the beginning and the ending of the twice tracks (0.5)