Microsemi, now part of Microchip, was developing an audio processing unit for the IoT. They were interested in replacing an off-the-shelf core and wanted to evaluate the flexibility of RISC-V for their processing needs. Using Codasip Studio, our automated customization toolset, and the lightweight Codasip L30 processor core as a starting point, they profiled their echo cancellation software and then compared different ISA scenarios including custom instructions.