要約
This paper presents a high-fidelity multiphysics numerical framework for simulating the acoustic performance of circumaural headphones coupled to a generic artificial ear, spanning the full audible frequency range from 20 Hz to 20 kHz. The proposed model integrates five essential physical phenomena: (1) pressure acoustics in air domains governed by the frequency-domain wave equation, (2) poroelastic wave propagation in foam cushion materials based on Biot's theory, (3) lumped-parameter electrodynamic driver modeling using Thiele-Small parameters, (4) frequency-dependent impedance characterization of perforated plates and acoustic meshes, and (5) physiological boundary conditions representing human skin and eardrum impedance. The computational domain incorporates a realistic 3D-scanned pinna geometry, an idealized ear canal (7.5 mm diameter, 19.8 mm length), and a headphone housing with internal acoustic chambers. Interior Perforated Plate conditions capture the acoustic resistance and mass effects of ventilation meshes, while Perfectly Matched Layers (PMLs) ensure artifact-free free-field radiation. Key findings reveal the frequency-dependent acoustic coupling mechanisms, demonstrating that the foam cushion acts as a low-pass filter at frequencies below 200 Hz, while perforated plates dominate the mid-to-high frequency response (200-2000 Hz and 2-20 kHz, respectively). The ear canal resonance at 3-4 kHz is successfully captured, with the coarse mesh model (28 GB RAM) showing excellent agreement with the fine mesh reference (100 GB RAM) up to 5 kHz, beyond which mesh resolution becomes critical. The study provides quantitative validation of SPL distribution on the pinna surface and at the eardrum, offering actionable insights for headphone design optimization. Computational trade-offs between accuracy and resource requirements are systematically evaluated, with recommendations for mesh sizing, solver configuration, and PML implementation. The validated framework establishes a robust digital twin methodology for virtual prototyping, parametric studies, and performance prediction in the audio industry.
