ABSTRACT
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.