Hybrid Millidecade Spectra: A Practical Format For Exchange Of Long-Term Ambient Sound Data

This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution. The format is a hybrid that uses 1Hz resolution up to 455Hz and millidecade frequency bands above 455Hz. This hybrid is appropriate for many types of soundscape analysis, including detecting different types of soundscapes and regulatory applications like computing weighted sound exposure levels. Hybrid millidecade files are compressed compared to the 1Hz equivalent such that one research center could feasibly store data from hundreds of projects for sharing among researchers globally.