Traditional Varnishes and Acoustical Properties of Wooden Soundboards
Mehran Roohnia, Mohammadreza Ghaznavi, Ahmad Rostamisan, Ahmad Jahanlatib, Abdolsaber Yaghmaeipo · Science International · 2013
Background: The impact of three different coating formulations, used traditionally in Iranian musical instrument industry, on acoustical properties of wooden soundboard was investigated. Methods: Shellac, Opaque Polyester Varnish (OPV) and Sandrous powder solution (50 and 5% solutions in Ethanol), were applied on pine wood and then the samples were tested using forced vibration technique. The measured acoustical parameters were specific modulus of elasticity, acoustic coefficient and acoustical converting efficiency. Results: The results indicated that, shellac lacquer caused the least negative impact on the acoustical properties of wood. Conclusion: To find better lacquers to improve the acoustical qualities of wood it should be considered that this new lacquer must be lighter in densities, exhibit higher modulus of elasticity and/or lower internal friction compare to raw unpolished wood.