I'm not going to claim to be an expert in the music department, but I will explain to you what I've experienced with the in game music since A19.
Your starting Config file will be "dsmcontent.xml" - This is the file that most of the music is configured for the game.
(Program Files (x86)\Steam\steamapps\common\7 Days To Die\Data\Config\dsmcontent.xml)
Currently, there are only 7 listed Static sound tracks in game (Traders and your bed/home day/night) that are viewable in the XML.
Its not too hard to change any of these static tracks into another track by pointing it at a Unity package. [Can go into details more if desired]
The problem you will encounter is everything else that is not these static tracks. Exploring/Suspense/Combat tracks are all Dynamic.
The music is literally weaved together from 15-20 second wave files to generate a ~2 minute track.
If you look at the XML file mentioned above, you can see how they weave it all together.
As noted in the patch notes for A19:
As of Alpha 19 there, are 31,558 unique combinations of music.
I can be wrong in this next statement, but as far as I am aware, people are still trying to understand the system and how best to use it.
There is no documentation from TFP in the xml files and we were just handed it to toy with when A19 was released.
1 - Exploring Tracks -> Only occur while your "Spook Levels" are low
2 - Suspense Tracks -> Only occur while your "Spook Levels" are high
3 - Combat Tracks -> Only trigger while 4+ zombies are aware of you / aggroed
4 - Static Tracks -> Trigger based on zone/range of a point.
So, while I don't think its impossible, just people don't fully know how the dynamic music works just yet and people still need to tinker / dissect it still.
- Mala Zedik