The chemical formula was derived from the spectrographic analysis. Five to eight overtones can generally be distinguished in a spectrographic analysis of the howling. Arrays of photosensors are also used in place of film in spectrographic systems. Like Shazam, those apps work by comparing spectrographic database for matches. Spectrographic analysis of acoustic sources is used as inspiration for orchestration. Spectrographic analysis showed that she was losing the top half of her range. Earlier data collection from reentry and breakup was mostly visual and spectrographic.