Every DM I have played with has done something different. One, used no music or sound. Another uses ambient music. One applies music only to battles, and it is a mixture of hard metal, but without words. Some of that is very video game oriented. Another mixes all kinds of stuff, including modern stuff like the band Modest Mouse or trance music. Another had us all contribute a few songs to the playlist.
When I DM, I often curate it depending on the scene. I like ambience for exploration pieces. If it is something, like on a ship, then I will pull ambience from Assassin's Creed (whatever the pirate one was), a few Ren Faire songs that deal with seafaring, etc. If we are roleplaying heavily, I will have a quieter ambiance. For combat, as mentioned earlier, Conan the Barbarian is an excellent soundtrack. But so is Skyrim, Morrowind, Witcher, etc. The Witcher is really good and also works well for ambience.
Lastly, there is a YouTube channel I just found. I feel like it is going to blow up any second, as it is perfect for gaming. It has all types of thematic RPG music. It is called Bardify, and I highly recommend it. It has ambience, like the sounds of a city. It has events like "Tense Negotiations" and "Long Rest." It has travel like "Mysterious Forest" and "Desert Excursion." It has a bunch of different kinds of tavern and combat music. One of my favorite combat pieces is called "LOw Level Combat." It has places like "Abondoned Ruins," "Feywild," and "Magic Item Shop." (But please don't tell everyone about this site, as I am using it for my next campaign. And I really want my players to have not heard all the songs.
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