a given recording rate and its frequency data is stored in any digital wave format in the computer. Such format represents sound by digital sampling. Pitch detection Pitch detection is often the detection of individual notes that might make up a melody in music, or the notes in a chord. When a single key is pressed upon a piano, what we hear is not just one frequency of sound vibration, but a composite of multiple sound vibrations occurring at different mathematically related frequencies. The elements of this composite of vibrations at differing frequencies are referred to as harmonics or partials. For instance, if we press the Middle C key on the piano, the individual frequencies of the composite's harmonics will start at 261.6 Hz as the fundamental frequency, 523 Hz would be the 2nd Harmonic, 785 Hz would be the 3rd Harmonic, 1046 Hz would be the 4th Harmonic, etc. The later harmonics are integer multiples of the fundamental frequency, 261.6 Hz ( ex: 2 x 261.6 = 523, 3 x 261.6 = 785, 4 x 261.6 = 1046 ). While only about eight harmonics are really needed to audibly recreate the note, the total number of harmonics in this mathematical series can be large, although the higher the harmonic's numeral the weaker the magnitude and contribution of that harmonic. Contrary to intuition, a musical recording at its lowest physical level is not a collection of individual notes, but is really a collection of individual harmonics. That is why very similar-sounding recordings can be created with differing collections of instruments and their assigned notes. As long as the total harmonics of the recording are recreated to some degree, it does not really matter which instruments or which notes were used. A first step in the detection of notes is the transformation of the sound file's digital data from the time domain into the frequency domain, which enables the measurement of various frequencies over time. The graphic image of an audio recording in the frequency domain is called a spectrogram or sonogram. A musical note, as a composite of various harmonics, appears in a spectrogram like a vertically placed comb, with the individual teeth of the comb representing the various harmonics and their differing frequency values. A Fourier Transform is the mathematical procedure that is used to create the spectrogram from the sound file’s digital data. The task of many note