I have exactly the same sound problem in South Africa (PAL-I) after doing a PAL conversion with the Micronas chip replaced as well.
The fix was implemented by Keith Wilkinson to the Australian version of palmod and the relevant new palmod package with some other cosmetic changes is available on the oztivo website.
The Palmod files in the software area seems to be older than this post.
Where can I get hold of the software to see if I can make it work for PAL-I?
Any support will be appreciated.