Hair tension influence on the vibroacoustic properties of the double bass bow

Abstract

The possibility of identifying vibration modes of a double bass bow, with a non-contact measurement of sound pressure in the Very Near Field (VNF) was investigated. This paper shows the application of this cost-effective method for vibroacoustic testings of the bow. The spectra of generated tones do not give sufficient information about a particular bow, but its vibroacoustical behavior provides additional properties. The visualization for all vibration modes below 4000 Hz was achieved by using sound pressure scanning in a VNF. Differences in the vibroacoustical properties of a double bass bow with different hair tension were analyzed.

Archives of Acoustics

“…Visualization of the oscillation modes of vibrating surface can be made by various optical methods, such as optical holography (Jansson et al, 1970) or laser Doppler vibrometry (Bissinger, Oliver, 2007;Kalkert, Kayser, 2010;Gren et al, 2006). A simple method presented in this paper, that proved to be good for this purpose without the need for special equipment, is the scanning of a sample in the Very Near Field (VNF) (Prezelj et al, 2013;Pantelić, Prezelj, 2014;Keele, 1974). Placing the microphone in VNF, only a few millimeters above the vibrating surface allows recording of sound pressure level that is proportional to local surface velocity (de Bree et al, 2004).…”

“…Contrary to this, to do near-field measurements means small changes in the position of the microphone resulting in large differences in the recorded response. By using this technique it is possible to achieve good visualization of mode shapes (Pantelić et al, 2020;Pantelić, Prezelj, 2014). The boundary of a VNF region is defined with the frequency and the distance of two adjacent nodes.…”