Measurements of friction instruments with high-speed camera and subpixel tracking
Rolf Bader, Florian Pfeifle, Niko Plath, Christian Koehn · The Journal of the Acoustical Society of America · 2015
Instruments working with stick-slip interactions not using a string were popular in the West since the invention of the glass harmonica by Benjamin Franklin in 1751. The Terpodion investigated was built by Buschmann in the mid-19th century as a friction instrument with a keyboard, where bars are pressed against a wooden rotating cylinder producing a sound. Using high-speed camera recordings, the only playable instrument today at the Viadrina museum in Frankfurt a.O. shows sinusoidal vibrations of the bars determining the played pitch while the radiated sound is highly complex. Therefore the instrument shows a fundamentally different stick-slip action compared to bowed instruments. Friction instruments of the East, like the singing bowls also show very sinusoidal-like sounds again caused by the stick-slip interaction. The New Ireland Lounuet, a finger-rubbed wooden block has both, a sinusoidal motion as well as a highly complex one which is to imitate bird and frog sounds. A systematic view on the different stick-slip interactions is suggested.