Update-caching technique for unit-generator-based sound synthesis

This paper describes 'update caching', a novel implementation technique for unit-generator-based sound synthesis that we developed. The trade-off between the computational efficiency benefit by the utilization of audio vectors and the resulting damage to timing precision in updating sound synthesis parameters is one of the most well-known problems in computer music software design. Our new technique first processes all the tasks in a DSP cycle and caches update events of sound synthesis parameters with timestamps. Then, the cached events are processed inside the signal processing loops of unit-generators during the computation of output samples. In most practical situations, such a technique allows sample-rate accurate updates of sound synthesis parameters without significant damage to the computational efficiency. While it does not improve the minimum feedback time, which is another problem caused by audio vectors, our technique provides a practical solution to the long-standing trade-off between computational efficiency and timing accuracy in unit-generator-based sound synthesis. Such an investigation into a novel implementation technique would be beneficial for the research and development of next-generation computer music systems.