Guitar Sound Parameters to Assess the Impact of Atmospheric Conditions on the Acoustic Qualities of the Instrument

Due to wood hygroscopicity, the properties of instruments with wooden elements are changing. The effect of this is an instability of the sound of the instrument. This paper presents a group of acoustic parameters describing changes in the sound of an acoustic guitar in an objective manner. During the research, we made some dedicated devices; among others an acoustic measuring chamber, a mechanism for repetitive string excitation, and a system enabling acoustic measurement with an equivalent noise level of 4.5 dBA. The instruments underwent a process of forced allocation of water molecules in wood (moisturizing). We developed parameters describing the sustain time, the character of sustain and tonal equalization of the sound of the instrument.