All-pass filter simulating cochlear delay characteristics and its musical applications

Abstract

This study explores the design and implementation of an IIR all-pass filter that simulates cochlear delay characteristics. This paper contains three topics: filter design, implementation, and musical evaluation. First, we designed an IIR all-pass filter to simulate cochlear delay characteristics by optimizing its zeros and poles to achieve the desired group delay. Additionally, the filter was implemented as a VST plug-in for real-time applications and is publicity available. Next, subjective evaluations were conducted to assess the musical impact of this filter. We applied the filter to snare drum, bass drum, bass guitar, and electric guitar to explore its musical applicability. Participants compared the filtered and original sounds. Percussion instruments received mixed feedback, with the filter sometimes described as “artificial.” In contrast, string instruments like bass guitar and electric guitar were rated as “impressive” and “attractive,” suggesting greater relevance for these sounds. Finally, we investigated the impact of the filter on guitar performance. Performance deviations from a metronome were measured under 10 different conditions by varying the number of filters and delay times. The results indicated that excessive delay introduced by the filter could disrupt synchronization during performances.