So many of you might already know that the default sound settings used by GOG aren't really good. So here is a short guide to get better settings:

Ok the only thing you need to know is how to mount and navigate folders in dosbox. Here is a short tutorial:
http://www.dosbox.com/wiki/Basic_Setup_and_Installation_of_DosBox

Now before you start with dosbox move the install.exe from the might and magic IV+V folder to the Might and Magic Swords of Xeen folder because Swords of Xeen has none and that one can also be used for the sound config.

Now run the install.exe in the Swords of Xeen Folder. When it asks you if you want to build World of Xeen type n because we don't want that. Now select Roland Canvas/GS and in the Next Step Sound Blaster 16. Select IRQ Channel 5 because thats the one the config file from the gog version uses and leave the rest at default. Type n when it asks you if it should update your Swords of Xeen Volume.

We are done with Swords of Xeen now for Might and Magic Iv+V use the same settings by running the install.exe in that directory.

For Might and Magic III use the first setting for graphics and the first or seventh for the sound.

Now exit and play the games normally.

There is a Problem with these Settings for World of Xeen and Swords of Xeen will use an annoying electric bell sound when you open doors or miss an enemy. I think this is so because the right sounds are missing from the sound font Windows uses. I tried MUNT but with that the music sounds different and definitely not right.

There was an older thread about sound settings in MM3 that you might want to look at:

http://www.gog.com/en/forum/might_and_magic_series/mm3_poor_sound_and_graphics_compared_to_snes_version

People discuss the various ways to set up the Roland Canvas for both MM3 and Xeen. Not sure about that electronic bell sound though.

Somewhere else (can't find it now) there was also a discussion of sound fonts in this forum, which will replace the default MIDI sounds with some really nice-sounding alternatives. I've never tried a sound font myself but it sounds like the ultimate way to make these older games that use MIDI sound better.

I also found that old thread. The problem is, MM4 and 5 don't allow you to set sound and music to different devices like MM3 does. I found out that you can set soundfonts with Bassmididriver but all soundfonts have the same Problem as Microsofts GS Wavetable Synth and play a electric Bell sound when you open doors or miss with your attacks.
The Problem seems to be, that the roland device seems to use a different table to look up the sounds and so uses the wrong sounds in some cases.
It would be really great if someone knows a sound font that works right.

i foound solution use mut MT-32 emulator+cm-32l rom. the music not better than roland canvas, but much better than soundblaster. especially foot step and door sound turn to correct

I just wanted to add that M&M3 was really made to be played with the Roland/Soundblaster combination. The Music and sound effects are much nicer, but some work is required to get the proper sound samples playing, instead of the incorrect default windows sound samples.

One way to do this is to download and install Munt, then download the ROMS for the sound samples, pointing Munt to them.
Then tell DOSBox to use the MIDI from Munt instead of the windows one.

The main issue that people have after this, is that certain sounds are missing because Munt is set to use the older MT32 PCM and Control ROMS instead of the newer CM32L PCM and Control ROMS. Their isn't much difference between the two except that the CM32L has an added 33 Sound effects, some of which are used in M&M3, this can be changed in Munt.

There are online guides and resources to help set all this up.
search Munt 32 emulator guide and dosboxwiki sound

You can use CM32 rom with munt, just set path in settings.