Graduate Student: Zane Rusk, Ph.D. Candidate, Department of Architectural Engineering, Minor in Acoustics

The auditory analogy to visualization is called “auralization” – the realistic presentation of a sound field to a human listener using some sound system. One way of auralizing sound fields for a listener is over headphones, rather than over a set of loudspeakers. Headphone-based auralization, or “binaural rendering”, is advantageous in that headphone technology is generally more accessible than loudspeaker technology when reproducing a sound field which involves sound coming from many directions; constructing a loudspeaker system that can present sound fields in full 360° around a listener takes significant infrastructure. Additionally, a controlled acoustic environment is required for high acoustic reproduction fidelity. However, loudspeaker-based auralization does not need to include additional processing to account for the acoustic effects which a listeners’ head has on the sound field, or the listener’s head movement within that sound field. A loudspeaker-based method physically creates an acoustic field in the space which the listener is situated in, whereas realistic binaural reproduction must incorporate the acoustic effects of the physical presence of the listener into a signal presented directly to the eardrums via headphones. The need to incorporate this information comes with associated challenges.

This PhD research seeks to improve binaural rendering methods. By investigating the perceptual effects of varying settings within a method, and “challenging” methods under different use cases and sound fields that are difficult to realistically render, the advantages and disadvantages of each method can be elaborated upon beyond the context currently given in literature. The sound fields to be evaluated in this research will be measurement-based, as opposed to simulated. With this new context, guidance on which binaural rendering method to choose for a given application (sound field) will be given, and improvements to specific binaural rendering method can be conceptualized. The discoveries made about methods and about sound fields may also lend themselves to novel parameterizations for room impulse responses.

The first part of the research project began in September 2020 as industry-sponsored research involving the perceptual evaluation of different configurations of a binaural rendering method. The second part will involve the measurement of “challenging” sound fields followed by their perceptual evaluation when rendered binaurally using various methods. The final part will pursue improvements to specific methods, the invention of new methods, or novel room acoustic parameterizations.