Since November I've been working on and off on a YM2151 sound card for the RC2014. This came about after talking to Sheila Dixon at the Retro Computer Festival in Cambridge, which inspired me to get working on the idea!
The first version of the board, I failed to wire up the interrupt pin. That's now been corrected, fixing the mdx file playback speed issues in the YouTube video, and I'm looking at doing another spin of the board.
Before doing that I though I'd post here to see if anyone has any design suggestions! The current schematic is attached.
The software is definitely rough round the edges at the moment and I've only tested mdxplay via z80ctrl's CP/M emulation.