Harmonicity and voice segregation in polyphonic music: Effects of age and hearing loss

Harmonic relations between components help to perceptually bind them and create the percept of pitch, usually relating to the common fundamental frequency. Speech segregation is somewhat but not drastically impaired when competing talkers are rendered inharmonic. Less is known about the role of harmonicity in polyphonic music. Both age and hearing loss may affect pitch perception, which in turn may influence the role of harmonicity in music and source segregation. This study investigated the role of harmonicity in listeners’ ability to count the number of voices in polyphonic music and to follow one voice in the presence of others. Performance was compared across groups of younger normal-hearing (yNH), hearing-impaired (HI), and age-matched normal-hearing (aNH) listeners. Performance declined in all groups as voice count and inharmonicity increased. The yNH group consistently outperformed aNH and HI listeners, with no significant differences found between the aNH and HI groups. Surprisingly, mean performance in all groups remained above chance in inharmonic conditions, suggesting that harmonicity is not critical for source segregation, even in music. [Work supported by NIH grant R01DC005216.]