The Sonic Explorer: Assessing Angular Structure and Spatial Organization in Sonotopes

Understanding the spatial organization of environmental sounds is essential for linking acoustic patterns with landscape structure and ecological processes. While ecoacoustics has made substantial progress in the temporal and spectral analysis of soundscapes, their directional and spatial components remain comparatively underexplored, particularly through low-cost and scalable approaches. Here we introduce the Sonic Explorer, a lightweight rotational sonic device designed to explore the angular structure and the spatial dynamics of sonotopes, defined as homogeneous spatial sonic units within a soundscape. The system is based on two opposed supercardioid microphones mounted on a rotating platform, coupled with a custom signal-processing framework that analyzes directional variations in sound intensity across frequency classes. Rather than aiming at sound pressure level measurements or full-sphere sound field reconstruction, the Sonic Explorer focuses on detecting spatial contrasts, dominant sound directions, and angular sound patterns relevant to ecological interpretation. Field tests conducted in a human-modified environment demonstrate the ability of the device to identify coherent directional acoustic structures associated with landscape configuration and dominant sound sources. The proposed approach provides a new practical and exploratory tool for landscape and soundscape research, enabling spatially explicit interpretations of sonic environments while maintaining low cost, portability, and adaptability.