The pure note is made only of the fundamental frequency 440Hz while the note played by instruments is made of many harmonics (2x440=880Hz, 3x440=1320Hz, etc.) You see that the amplitude of the harmonics is different for each instrument, which characterizes their respective timbre.Īs mentioned above, each note corresponds to a fundamental frequency. The next figures shows how the note A4 (A on the 4 th octave) is represented as a pure note and as a note played by different instruments. This is the musical instrument signature, more specifically referred to as the timbre. The organization of the harmonics with respect to each other allows one to recognize the instrument being played. Harmonics components have a frequency that is an integer number times the fundamental frequency. This is because each note is usually made of a fundamental frequency but also a set of harmonics. However, the same note played by different instruments does not produce the same sound. The next figure shows you the most common notes with their corresponding fundamental frequency.įigure 2.1: Notes and their fundamental frequency A pure note is made of a single sinusoid at the fundamental frequency. Each semitone corresponds to a specific note. Each octave is made of twelve semitones, also referred to as half steps. The musical range is divided in many octaves. For instance, by shifting up the pitch of a man who is singing, we could end up with a sound where it sounds like a woman is singing instead. What pitch shifting does is it takes the sound produced at a given pitch and changes its frequencies. There are both men and women singing but the women will have a higher pitch than the men. The best way to understand this is to look at a choir. The pitch of a sound corresponds to the set of frequencies the sound is made of.

The first thing to do is to make sure we understand what is pitch shifting. that does not work 2.4 The good way to do it Pitch shifting 2.1 Music theory and timbre 2.2 Frequency scaling 2.3 A simple solution.

Octave shifter 2