Perspectives on immersion through laser doppler vibrometry

Recording sounds from novel perspectives is of particular interest in the creation of immersive sound design. Sound design that provides an immersive experience for the listener is increasingly relevant, with widespread use across music, film, computer games and other media modalities. Laser doppler vibrometry (LDV) is a non-contact technique for the measurement of mechanical vibration. LDV is used in a wide range of research and engineering applications, including biophysics, microelectronics, and the automotive industries. In audio and acoustics research, LDV can be used instead of piezoelectric transducers where high sensitivity, non-contact measurements are important to ensure the accurate capture of vibrations over a wide frequency range. However, while its use for data gathering and analysis is very well established, its potential as a creative tool in immersive sound design has seen very little research. In this paper we show that LDV can provide a unique and creatively valuable sonic perspective on sound making objects. We demonstrate how an LDV system can be optimised for such use, and allow high quality vibration recordings to be made and used in the creation of immersive sound and music experiences. The results build on what is possible with commonly used piezoelectric transducers by harnessing the non-invasive nature of LDV. The ability to measure vibration at a single point with very wide spectral resolution, and to focus on the vibration of both large and tiny objects, reveals a new sonic world with significant potential in the development of immersive sound design.