Directional coherence loss coefficients for characterizing scattering distributions in enclosures

Area of Science:

• Acoustics
• Signal Processing

Background:

• Sound fields in enclosures are complex, influenced by reflections and scattering from interior elements.
• Quantifying coherence loss is crucial for accurate acoustic modeling, especially in furnished rooms.

Purpose of the Study:

• To introduce directional coherence loss coefficients (DCLCs) for quantifying angular sound field coherence loss.
• To develop a hybrid model for sound field reconstruction using DCLCs.

Main Methods:

• Sampling sound fields with a spherical receiver and decomposing into plane waves using spherical harmonics expansion.
• Analyzing time-dependent coherence coefficients between directional impulse responses (IRs) in furnished and empty rooms.
• Deriving DCLCs from coherence coefficients to differentiate coherent (specular) and incoherent (scattering) sound components.

Main Results:

• DCLCs were extracted from simulations and measurements in rooms with varying element distributions and transducer positions.
• A hybrid model using DCLCs accurately reconstructed sound fields, showing agreement with ground truth metrics.
• The study verified DCLCs' ability to characterize localized scattering distributions.

Conclusions:

• Directional coherence loss coefficients (DCLCs) provide a novel method for quantifying sound field scattering.
• The proposed hybrid model, guided by DCLCs, offers improved sound field reconstruction in complex acoustic environments.