Array-Aware Ambisonics and HRTF Encoding for Binaural Reproduction With Wearable Arrays

TL;DR

A novel method for binaural reproduction from arbitrary microphone arrays, based on array-aware optimization of Ambisonics encoding through Head-Related Transfer Function (HRTF) pre-processing, which offers a practical solution for spatial audio rendering in applications such as virtual reality, augmented reality, and wearable audio capture.

Abstract

This work introduces a novel method for binaural reproduction from arbitrary microphone arrays, based on array-aware optimization of Ambisonics encoding through Head-Related Transfer Function (HRTF) pre-processing. The proposed approach integrates array-specific information into the HRTF processing pipeline, leading to improved spatial accuracy in binaural rendering. Objective evaluations demonstrate superior performance under simulated wearable-array and head rotations compared to conventional Ambisonics encoding method. A listening experiment further confirms that the method achieves significantly higher perceptual ratings in both timbre and spatial quality. Fully compatible with standard Ambisonics, the proposed method offers a practical solution for spatial audio rendering in applications such as virtual reality, augmented reality, and wearable audio capture.

Figures (9)

• Figure 1: Microphone positions on a rigid sphere with locations $(\theta, \phi)$: $\left\{ (90^{\circ}, -80^{\circ}), (72^{\circ}, -40^{\circ}), (108^{\circ}, 0^{\circ}), (72^{\circ}, 40^{\circ}), (90^{\circ}, 80^{\circ}) \right\}$. The estimated ear locations correspond to $(90^{\circ}, \pm 90^{\circ})$.
• Figure 2: The error $\hbox{$\xi$}_{\text{null}}$ in dB, as defined in (\ref{['cond:yV0V0y<th']}), for the steering matrix of the array described in Sec. \ref{['section:Array Setup']}. The evaluation is performed for two sets of SH orders. The top plot corresponds to SH orders $(n,m) = (0,0), (1,-1), (1,0), (1,1)$, while the bottom plot represents $(n,m) = (2,-2), (2,-1), (2,0), (2,1), (2,2)$.
• Figure 3: The LSE of the ASM filter in dB, $\xi_{nm,\text{LSE}}$ for SH orders $(n,m) = (0,0), (1,-1), (1,0), (1,1)$, as defined in (\ref{['cond:effective magnitude']}).The magnitude is evaluated for the array configuration described in Sec. \ref{['section:Array Setup']}.
• Figure 4: Measure of the error in (\ref{['eq:e=(1-a)e+ae^Mag']}) for ASM + MagLS HRTF, ASM + proposed MagLS HRTF, for both ears. The results are shown with azimuthal head rotations of $0^\circ$, $30^\circ$, and $60^\circ$ from top to bottom, where the rotation is applied using Wigner-D functions.
• Figure 5: ILD as in (\ref{['eq:ILD']}) and ILD error as in (\ref{['eq:ILD_error']}) for ASM + MagLS HRTF and ASM + proposed MagLS HRTF. Results shown for head rotations of $0^\circ$, $30^\circ$, and $60^\circ$.