Biofizikalni temelji vibroakustične dijagnostike zvučnosti rastućeg stabla

Abstract

At the turn of the third millennium, scientists and experts of many countries are still trying to puzzle out ‘the mystery of Stradivari’, using for this purpose advanced technological solutions in the fi elds of physics, mathematics, chemistry, biology, etc. It has been undoubtedly proved that one of the basic secrets of the great master’s violin sounding is in the recognition of the proper material. Unfortunately, Stradivari, Amati, Guarneri and other great representatives of the Old Italian school did not leave any hints, but it has been recorded that they selected wood for the string-plate, the main sounding part of a violin, by tapping, and they designed an instrument judging from the ‘sonority’ factors known to them only. Using modern scientific terms, it is possible to ascertain that it was the professional skill of the master to decode the percussion-acoustic response of the source material that predetermined the quality of the product. The results of the work done cannot claim to disclose any secrets in the field. For this purpose, significant complex research is necessary, both fundamental and applied, integrating the efforts of scientists and experts in different areas: physicists, acousticians, wood scientists, foresters and, the main thing, the recognized masters in the sphere of manufacturing corresponding musical instruments. This paper presents the fi rst results of implementing the technique based on the excitation of fl uctuations of a trunk by a special shock device with further recording, decoding and analyzing acoustic response, matching it with the conditions of growth and general morphology of a tree, i.e. its size, crown form and length, trunk habit, etc. As such a work does not have any analogues and, consequently, there is no ‘acoustic standard’ of a sounding tree for the moment, the data obtained were analyzed in accordance with general provisions of acoustic diagnostics. Thus, the basic acoustic parameters accepted are vibrating activity, power consumption of spectral characteristics, amount of resonance peaks, vibration absorbing and damping, frequency distribution of a spectrum.

Keywords

• spruce tree
• sounding wood
• shock device
• acoustic response
• impedance
• vibration absorbing
• frequency
• histogram