Systematic Development of a Phased Speaker Array for Optimal 3D Audio Reproduction

Abstract

In recent years, "spatial audio" has seen a dramatic uptick in popularity. The demand for increased immersion in many forms of auditory media seemingly led several industry leaders to pursue 3D audio playback. Almost all of these developments, however, are effective for only a single listener. In a home theatre setting, surround sound systems seek to provide a similar type of auditory immersion through physical placement of sound sources in 3D space. While this approach can be effective for multi-listener playback, modern surround systems suffer from both bulkiness and over-complexity. Moreover, both approaches rely on specialized mixing and object-oriented audio, providing little support for decades of stereo recordings. This project provides an alternative to these typical 3D audio systems through a one-dimensional phased speaker array. Using a combination of acoustic beamforming and cross-talk cancellation filters (along with head-tracking), this system is capable of directing audio towards multiple listeners' ears and provides enough channel isolation for 3D audio perception. More specifically, it utilizes spectral division method beamforming, frequency domain beam steering, and Edgar Choueiri's BACCH Filters for cross-talk cancellation. This report details the software optimization process for these techniques, along with the design and manufacturing of a new physical array. This design is primarily informed by binaural measurements and acoustic pressure simulations. Using these tools and methods, the final system improves upon previous hardware and software to provide 3D audio playback unmatched by existing systems of the same form factor.