Glossary definition of 'Sample Rate Conversion'

(SRC) The process of converting a digitally sampled signal from one sample rate to another (e.g., 96kHz to 44.1kHz), while introducing as little distortion and noise as possible.

Sample-rate converters have had a bad name amongst audio engineers. They have been regarded as sounding so bad that it is often preferred to rate-convert through analogue using good quality D/A and A/D converters.

The Prism Sound Synchronous Sample Rate Converter (SSRC) brings new quality to the rate conversion process. The plot below shows a 997Hz tone at –1dBFS being converted from 96kHz sample rate to 44.1kHz sample rate by Prism Sound SSRC in the ADA-8XR:



As can be seen from the plot, the largest spurious component is at –151.65dBFS, which represents a huge improvement over competitive asynchronous rate converters, whose imprecise conversions produce large and obtrusive aharmonic distortion components which have given sample rate converters their characteristic 'sound' in the past.