WYZTracker is a tool developed by Augusto Ruiz (interface in english and spanish), from Retroworks, that can be used to compose music for WYZPlayer.

WYZPlayer is a Z80 player for the AY-3-8910 sound chip (a 3-voice PSG : Programmable Sound Generator designed by General Instrument) used by (and for) the Amstrad CPC, MSX and Spectrum. It can be used for games and demos due to its minimal use of CPU and RAM, the player takes little code and all musics are compressed.

Finally, you can use cpcwyzlib by Raul Simarro, an Amstrad CPC library to play wyztracker tunes with SDCC. He also wrote the cpcrslib used with z88dk.