For his graduate research, Ian studied changes in the perception of immersion when listening to ambisonic nature recordings. The abstract for his thesis is below, and a full version is available here.
Abstract from Comparative Perceptual Evaluation of Ambisonic Order in Nature Recordings
Higher order ambisonics have demonstrated technical improvements over lower orders that can lead to a greater sense of immersion in musical recordings. Music is performed on instruments and in locations that are well known and finite. Nature, in contrast, has sounds and environments that are seemingly endless. Natural sounds occur at all depths and positions, and sound sources are colored by external forces like weather, geography, and time. Since the sounds of nature differ so greatly from music, the variations in listening perception, particularly regarding immersion, are unclear. In the case of ambisonic recording, the effects of order are unexplored. This paper aims to understand the impact that increased ambisonic order has on the perception of immersion in nature recordings.
A perceptual evaluation was performed in which participants were asked to listen to three nature recordings that were encoded from first through third order. Each recording was presented in pairs of different orders; the listener was asked to select which was more immersive. The selection rate of the higher or lower order in each pair was analyzed for each recording.
The results show no significant correlation between ambisonic order and immersive potential, leading the author to conclude that meaningful immersion can occur at any ambisonic order. Immersive nature recordings can then be made with lower order microphones which tend to be less complicated, less expensive, and more compatible with recording hardware, software, and distribution platforms than higher orders.