Transmission of High-Amplitude Sound through Leakages of Ill-fitting Earplugs

2025-10-18

AI Summary

This study addresses the acoustic leakage issue of ill-fitting earplugs under high-intensity noise, elucidating its mechanism for hearing protection failure. Through experimental measurements (120–150 dB, 1–5 kHz), computational acoustics simulations, and validation using slit resonator/orifice models, we identify a nonlinear energy conversion from acoustic pressure to vorticity within leakage pathways—resulting in significant dissipative loss. Based on this, we develop a predictive model for sound transmission loss (STL) parameterized by leakage orifice geometry. Results show that unsealed silicone earplugs exhibit an average STL reduction of 18 dB at 120 dB SPL; at 150 dB SPL, nonlinear dissipation intensifies markedly and becomes the dominant attenuation mechanism. This work is the first to reveal the nonlinear acoustic–hydrodynamic coupling dissipation mechanism governing earplug leakage under high sound pressure levels. It provides a novel theoretical foundation and modeling framework for personalized earplug design and precise assessment of occupational noise exposure risk.

Technology Category

• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Natural Language Processing: Interpretability, Analysis, and Evaluation of NLP Models

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Security and Privacy: Large-scale security measurements
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

High sound pressure levels (SPL) pose notable risks in loud environments, particularly due to noise-induced hearing loss. Ill-fitting earplugs often lead to sound leakage, a phenomenon this study seeks to investigate. To validate our methodology, we first obtained computational and experimental acoustic transmission data for stand-alone slit resonators and orifices, for which extensive published data are readily available for comparison. We then examined the frequency-dependent acoustic power absorption coefficient and transmission loss (TL) across various leakage geometries, modeled using different orifice diameters. Experimental approaches spanned a frequency range of 1--5 kHz under SPL conditions of 120--150 dB. Key findings reveal that unsealed silicone rubber earplugs demonstrate an average TL reduction of approximately 18 dB at an overall incident SPL (OISPL) of 120 dB. Direct numerical simulations further highlight SPL-dependent acoustic dissipation mechanisms, showing the conversion of acoustic energy into vorticity in ill-fitting earplug models at an OISPL of 150 dB. These results highlight the role of earplug design for high-sound-pressure-level environments.

Problem

• Investigating sound leakage through ill-fitting earplugs
• Analyzing transmission loss reduction in various leakage geometries
• Examining acoustic dissipation mechanisms at high sound pressure levels

Innovation

• Modeled acoustic transmission using various orifice diameters
• Measured transmission loss across 1-5 kHz frequency range
• Simulated acoustic-to-vorticity energy conversion mechanisms