@aodohertyI know this thread's a year and a half old, but it seems like basically everyone misunderstood the request (no, we don't want to play music from an external media player, please stop suggesting that), so I feel the need to resurrect the thread.
There's a mod on ModTheSims called "In-Game Music" that lets you mute certain Build/CAS/neighborhood music tracks. By default, the mod erases ALL Sims 4 music, BUT if you use a utility called s4pe, you can edit the mod files to erase the values of the songs you want to keep. With that method, you can selectively disable the background music from very specific expansion packs, while leaving others (like the vanilla Sims 4 build music) intact.
I realize this isn't the most straightforward answer, and not everyone's comfortable with modding, but this is the closest we're gonna get until EA includes an option in the game itself. Why they haven't already is beyond my comprehension. But at least there's an option to fix their mistake, even if it's not the easiest option in the world.
If anyone would like, I can try and upload some of my edited files for everyone to use. That way y'all won't have to edit the values yourselves.
CM Edit: Do not link to mods on AHQ please.
