FPGA implementation of 1D wave equation for real-time audio synthesis

Abstract

The paper addresses the potential benefits of using a field programmable gate array (FPGA) as opposed to a traditional processor for music synthesis. The benefits result from the use of a cellular design, with each cell performing identical operations on its own state and the states of its neighbours. This gives advantages of design simplicity through inherent parallelism. A cellular model which has previously been used for music synthesis is the mass spring paradigm, and this model is implemented on an FPGA. On a sequential processor, the clock speed requirements of this model increase as N2 (where N is the number of cells), whereas the clock speed requirement increases as N on an FPGA (if the cells can be made small enough that available area on the chip is not a constraint). To make the cells small enough, a bit-serial design was used. This work was performed to advocate the FPGA as a stand-alone live performance music synthesis platform, which has the potential to be reconfigured for example in performance, between synthesis techniques as different sound patches are selected. The paper considers in particular the mass-spring model, because it demonstrates the type of music synthesis technique for which FPGAs provide the greatest potential benefit. The capability to reconfigure combined with the high performance that can be achieved using cellular design suggests that the FPGA is an ideal platform for a live performance hardware music synthesiser, combining the flexibility of software with the speed of a custom ASIC.