Bouz announced that he’s working on an AICA audio driver that will be able to process S3M stereo files directly through the sound chip. This should be an improvement to the way the KOS driver handles it, since it uses the main SH4 CPU to treat sound and the AICA co-processor for the balance.
You can get a demo for the driver (ELF file for dc-tool) at DC-France
Source:Dreamcast.es