Heroes II stores its sounds as a raw WAV file, a WAV file without headers. 

See Packaging Resources to learn how to extract the sound files from the original game. You can open and edit the .82M sound files using any sound editor capable of importing raw WAV data. We recommend Audacity, http://audacity.sourceforge.net/about/ . Use the "Import Raw Data" menu option and set it to import as 8-bit mono with a sampling rate of 22050.

You can make sounds using any sound editor and then export them in the same format. If you are using Audacity, enter its preferences, and, under "Quality," set Sample Rate to 22050, and, under "File Format," set it to export its Uncompressed Export Format to "WAV (Microsoft 8-bit PCM)".

Finally, you will need to strip the 44-byte header. Run the following command on a Mac or Unix-based system:

dd bs=44 skip=1 if=sound.wav of=sound.82M

If you skip this step and just rename the sound to an 82M file, you can still import it into the game, but there will be a brief clicking noise at the beginning.

While all of the original games sounds are .82M files, the game also supports a couple different formats. The "8", "2", and "M" are actually codes that tell the game how to read the file, similar to the WAV headers which it omits. Changing the "2" to a "1" or "4" (i.e.: .81M and .84M files) means that the sample rate should be 11025 or 44100. Changing the "8" to a "6" or the "M" to anything else will increase the "sample type," although we don't know what this means.