You can use the &F888/&F988 audio ports and the CRTC cursor registers to program the raster interruption located at &0066. Both works on PlayCity and Play2CPC.
= ResourcesLinks =*[https://www.cpcwiki.eu/forum/amstrad-cpc-hardware/play2cpc-plus2cpc-ii-extra-sound-channels-and-rewritable-cartridges/ Topic on CPCWiki forum]*https://abalore.com/play2cpc/