Harmonic/Percussive Sound Separation and Spectral Complexity Reduction of Music Signals for Cochlear Implant Listeners

Cochlear implant (CI) users suffer from limitations in music perception and thus prefer music which has a clear rhythm/beat and is played with only a few instruments. Therefore, existing music pre-processing methods aim to enhance music signals for CI users by either emphasizing preferred voices or reducing the spectral complexity of the signals. In this work, a music pre-processing scheme is described which combines these approaches and is applicable to a wider variety of music genres. The proposed method is evaluated and compared to other recently developed methods using instrumental measures and a listening test with vocoded pop/rock music excerpts and normal hearing listeners. Unprocessed popular music pieces as well as different processed versions were rated comparatively in terms of distinctness of drums, distinctness of melody, and the overall impression. The listening test showed significantly better ratings for the proposed method compared to unprocessed music and most of the other processing schemes. As the instrumental measures also indicate improvements, the proposed combined strategy is a promising candidate for music enhancement for CI listeners.