On the Impact of Ground Sound

TL;DR

This paper models ground impact sound using elastodynamics to identify when ground sound influences perception, especially in soft ground impacts with dense objects or low impact angles.

Contribution

It introduces an analytical elastodynamic model for ground sound, enabling realistic synthesis and analysis of impact sounds including ground effects.

Findings

Ground sound is perceptible when modal sound is inaudible.

Soft ground and low impact angles enhance ground sound audibility.

The model provides a closed-form expression for ground surface acceleration.

Abstract

Rigid-body impact sound synthesis methods often omit the ground sound. In this paper we analyze an idealized ground-sound model based on an elastodynamic halfspace, and use it to identify scenarios wherein ground sound is perceptually relevant versus when it is masked by the impacting object's modal sound or transient acceleration noise. Our analytical model gives a smooth, closed-form expression for ground surface acceleration, which we can then use in the Rayleigh integral or in an "acoustic shader" for a finite-difference time-domain wave simulation. We find that when modal sound is inaudible, ground sound is audible in scenarios where a dense object impacts a soft ground and scenarios where the impact point has a low elevation angle to the listening point.