An old sound demo from the TK85 I think ...
For those who want to program the MrX or ZONX from basic.
Another nice demo.
The well known pink panther theme.
MrX can do digitized sounds. Here some samples.
A PT3 Player. Google the WWW for thousends of PT3 files.
Some games with sound for the ZX81. Most of them are poor.
The manual. Covers the setup, programming and the port k3.
Na, das dürfte reichen :-)