Is there a way to turn off all music in Fallout: NV?

It is possible! However, when you are in a location where "Johnny Guitar" is playing you will need to find the little annoying radio or jukebox and turn them off. Unfortunately some locations like the casinos have their own music speakers that you can not shut off. That helps significantly cut the tunes from the 1950s out so you do not have to explore or handle business to "Blue Moon" or "Lone Star" (my top personal hatred songs lol) So far only Chet and Trudy in Goodsprings have turned their radio back on after the game console was off for a while. Hope that is helpful! And feel free to message if ever want to chat about the game, I am really into it too.