I have Might and Magic 1 from the Might and Magic Humble Bundle. After installation there’s a homm1.gog file which is actually and ISO containing the original music in 82M format.
With info from the Reverse Engineering Wiki page on the 82M file extension I’ve come up with the following command to convert these music files using ffmpeg:
for %f in (*.82M) do ffmpeg -f s8 -ar 22050 -ac 1 -i %f -acodec pcm_u8 -ar 22050 -ac 1 %~nf.wav
This will convert each 82M file to the appropriate WAV format. If you have 82M files from Heroes of Might and Magic 2, you should be able to change the option s8 to u8.