Mode studies of plucked stringed instruments: Application of holographic interferometry
Bernard Richardson

The acoustics group at Cardiff have used holographic interferometry for many years to study the vibrations of musical instruments. After a brief review of the technique and equipment and the particular strengths and weaknesses of this analysis tool, the paper will describe measurements on historic, modern and experimental guitars and related instruments. These studies highlight the effects of strutting and bracing patterns used on the underside of the soundboard and the size and positioning of the bridge, which give insight how the design and construction of these instruments affects their mechanical vibrational properties and their acoustical function.
Whilst there will be some technical elements in this paper, the intention is to assist the maker in interpreting these intriguing images and using them to make informed decisions about modifications in the designs of musical instruments.