Immersive object-based spatial audio is now firmly established in the music industry as the standard for production, distribution, and playback. The number of automobiles integrating such content to provide premium entertainment experiences is steadily increasing, driving the development of new audio rendering techniques. While loudspeakers integrated into automotive headrests have been around for more than 50 years, they have not yet achieved status as a standard feature in new cars. However, they represent a powerful tool for reproducing immersive audio by enabling the creation of personal sound zones with reduced passenger distraction while effectively complementing existing cabin speakers. We conduct subjective assessments using paired comparison experiments to measure preference and multiple spatial audio attributes. We plan to model the resulting probability outcomes using probabilistic choice models, such as Bradley-Terry-Luce rank ordering. We expect the findings of this work to provide a technical roadmap for the integration of headrest speakers in next-generation automotive spatial audio systems.
