Cochlear detection of double-slip motion in cello bowing

TL;DR

This study demonstrates that a cochlear FDTD model can accurately detect double-slip motions in cello bowing sounds, revealing the ear's ability to perceive complex bowing behaviors through spike timing analysis.

Contribution

The paper introduces a cochlear FDTD model that effectively detects double-slip bowing motions in cello sounds, advancing understanding of auditory perception of complex string instrument techniques.

Findings

Cochlear model accurately represents double-slip behavior in spike intervals.

Double-slip detection aligns with amplitude peak detection in cochlear spikes.

Ear can perceive complex bowing motions through spike timing analysis.

Abstract

A double-slip motion of a cello sound is investigated experimentally with a bowing machine and analyzed using a Finite-Difference Time Domain (FDTD) cochlear model. A double-slip sound is investigated. Here the sawtooth motion of normal bowing is basically present, but within each period the bow hair tears off the strings once more within the period, resulting in a blurred sound. This additional intermediate slip appears around the middle of each period and drifts temporally around while the sound progresses. When the double-slip is perfectly in the middle of one period the sound is that of a regular sawtooth motion. If not, two periodicities are present around double the fundamental periodicity, making the sound arbitrary. Analyzing the sound with a Wavelet-transform, the expected double-peak of two periodicities around the second partial cannot be found. Analyzing the tone with a cochlear FDTD model including the transfer of mechanical energy into spikes, the doubling and even more complex behaviour is perfectly represented in the Interspike Interval (ISI) of two adjacent spikes. This cochlear spike representation fits perfectly to an amplitude peak detection algorithm, tracking the precise time point of the double-slip within the fundamental period. Therefore the ear is able to detect the double-slip motion right at the transition from the basilar membrane motion into electrical spikes.