This is determined by The number of overtones present that are harmonics, the number of overtones that are inharmonic, and the relative intensities or strengths of the overtones. Analysis and Synthesis of Sounds Analysis is the process of dividing a complex wave into its fundamental frequency and its various overtones and determining the relative strengths of each. The process is called Fourier Analysis . Synthesis is just the opposite. It is the combining together of pure tones of various proportions to produce a complex tone.
Additive synthesis creates complex waveforms by adding simple waveforms togther.
Subtractive synthesis creates new waveforms by filtering out certain harmonics.