Xylophone collection
The frequency measurements were obtained using the software Sonic Visualiser, based on audio recordings of the xylophones made by the research team in 2023–2025. The physical condition of the instruments is satisfactory; however, the absence of calabash resonators may alter the sound radiation and the acoustic effect of the tuned wooden keys. In addition, the project team cannot entirely rule out alterations resulting from historical collection processes or past scientific studies, which may have affected the original tones and frequency measurements (for example, MO.0.0.10843). The Western pitch names are given relative to the measured frequencies, with most tones deviating slightly from absolute Western pitches. For example, the first tone of MO.0.0.14308 is 516 Hz (C5 - 23 cents), and the second tone is 1065 Hz (C6 - 31 cents).