Advanced system options for binaural rendering of Ambisonic format

Ambisonics uses a well-respected soundfield representation and thus may become a standard in soundfield transmission, storage, and reproduction. Then we will need signal processing options in order to decode and apply the Ambisonic format universally in various applications from loudspeaker to headphone reproduction. More specifically, the use of Ambisonics is envisioned also in mobile applications where headphone reproduction is clearly preferred. In this context, we present two different system options for the advanced implementation of binaural soundfield rendering. Both options utilize the concept of virtual loudspeakers and subsequent binaural rendering via HRTF. In order to achieve spatial realism, one option relies on adaptive soundfield rotation in the Ambisonic domain to mimic a corresponding head rotation of the listener in the given soundfield. The other system option relies on a new continuous-azimuth HRTF format for direct representation of head rotations within the virtual loudspeaker setup. For both system options, we will discuss the pros and cons regarding the implementation. We conclude with a comparison of the resulting localization accuracies in listening tests.