An extended two-dimensional vocal tract model for fast acoustic simulation of single-axis symmetric three-dimensional tubes

TL;DR

This paper presents a novel 2.5D vocal tract model that extends 2D wave simulation to efficiently replicate 3D symmetric tube acoustics, improving speed and resolution requirements for vocal analysis.

Contribution

The paper introduces an extended 2.5D FDTD model that incorporates tube depth, enabling faster and more accurate simulation of symmetric 3D vocal tracts compared to previous 2D approaches.

Findings

Achieves faster acoustic simulation of symmetric 3D tubes

Reduces resolution requirements for accurate modeling

Demonstrates effectiveness in static vowel modeling

Abstract

The simulation of two-dimensional (2D) wave propagation is an affordable computational task and its use can potentially improve time performance in vocal tracts' acoustic analysis. Several models have been designed that rely on 2D wave solvers and include 2D representations of three-dimensional (3D) vocal tract-like geometries. However, until now, only the acoustics of straight 3D tubes with circular cross-sections have been successfully replicated with this approach. Furthermore, the simulation of the resulting 2D shapes requires extremely high spatio-temporal resolutions, dramatically reducing the speed boost deriving from the usage of a 2D wave solver. In this paper, we introduce an in-progress novel vocal tract model that extends the 2D Finite-Difference Time-Domain wave solver (2.5D FDTD) by adding tube depth, derived from the area functions, to the acoustic solver. The model combines the speed of a light 2D numerical scheme with the ability to natively simulate 3D tubes that are symmetric in one dimension, hence relaxing previous resolution requirements. An implementation of the 2.5D FDTD is presented, along with evaluation of its performance in the case of static vowel modeling. The paper discusses the current features and limits of the approach, and the potential impact on computational acoustics applications.