No abstract

A non-contact method of sound reproduction has great potential for sound archives, aiming to transfer the audio content from early sound recordings such as wax cylinders, which may otherwise be 'unplayable' via conventional stylus methods. If non-contact, optical methods are to be considered a viable solution for sound archives, a method for quantifying the quality of the reproduced audio signal needs to be developed. In this paper, methods for recovering the audio signal from a discrete surface map of a cylinder recording measured via non-contact surface metrology are described. A test cylinder recording, encoded with sinusoids provides the basis for a signal quality analysis. Noncontact and conventional stylus methods of sound reproduction are then compared using the same test cylinder. It is shown that non-contact methods appear to have distinct advantages over stylus reproduction, in terms of reduced harmonic distortion and lower frequency modulation.