The Significance of the Non-Harmonic "Noise" Versis the Harmonic Series for Musical Instrument Recognition

Sound produced by Musical instruments with definite pitch consists of the Harmonic Series and the nonharmonic Residual. It is common to treat the Harmonic Series as the main characteristic of the timbre of pitched musical instruments. But does the Harmonic Series indeed contain the complete information required for discriminating among different musical instruments? Could the non-harmonic Residual, the “noise”, be used all by itself for instrument recognition? The paper begins by performing musical instrument recognition with an extensive sound collection using a large set of feature descriptors, achieving a high instrument recognition rate. Next, using Additive Analysis/Synthesis, each sound sample is resynthesized using solely its Harmonic Series. These “Harmonic” samples are then subtracted from the original samples to retrieve the non-harmonic Residuals. Instrument recognition is performed on the resynthesized and the “Residual” sound sets. The paper shows that the Harmonic Series by itself is indeed enough for achieving a high instrument recognition rate; however, the nonharmonic Residuals by themselves can also be used for distinguishing among musical instruments, although with lesser success. Using feature selection, the best 10 feature descriptors for instrument recognition out of our extensive feature set are presented for the Original, Harmonic and Residual sound sets.