Ulezo Supplemental Materials
Image 1: Common instrumentation for recreational (L) and ceremonial (R) settings
Image 2: Ngoma pegs during (L) and after (center) head attachment compared to the large protruding pegs of the Ga kpanlogo (R)
Image 3: Heating the drums by fire in Mongu, Zambia on 25 March 2022; (L-R) Kashewa Kapalu, Chinyama Kasanga, Kasanga Nsamba
Image 4: Ulezo made by Kapalu Lizambo in Zambezi, Zambia in 2022
Image 5: Members of Lenga Navo applying ulezo in Zambezi, Zambia on 12 June 2022; (L-R) Kapalu Lizambo on shina, Musumale Chijika on ngoma yahakachi, Vocia Kahilu Kapalu on ngoma yakusongo, Innocent Kapepa on ngoma yakasumbi
Figure 1: The Luvale drum timbre descriptor spectrum with English translation and instructions on achieving these timbres
Figure 2: Spectral centroid
Figure 3: Spectral decrease
Figure 4: Spectral roll-off
Figure 5: Temporal centroid, from Elliot et al., (2013, p. 396)
Figure 6: Zero-crossing rate
Figure 7: Box plot showing spectral centroid values for each tuning stage
Figure 8: Box plot showing spectral decrease values for each tuning stage
Figure 9: Box plot showing spectral roll-off values for each tuning stage
Figure 10: Box plot showing temporal centroid values for each tuning stage
Figure 11: Box plot showing zero-crossing rate values for each tuning stage
Figure 12: Timbral change of open strokes in the acoustic and perceptual domains