I have tried and succeeded in putting music in a game. For any console that uses composite cable you can do it. All you do is turn the in game music to 0 and unplug the red stereo cable. Take something you are playing your music on and plug its red wire in where you just unplugged the other red wire. There you go! Which means close to every game has custom soundtrack! I do not know if any of you already know about this. If none of you do I hope this helps!😃
Custom soundtrack!
EDIT: or, just set the games music to 0, then insert a CD into your stereo hifi system.
Headphones FTW. During Melee/Brawl matches, we'd turn the sound all the way down, and hook up one of our iPods to the stereo we use next to the TV. Awesome matches.
Some games this works better for than others. Fighting and racing games are two genres that it almost always works for. Games like Zelda or Final Fantasy, not so much.
Oh also, you lose half your Sound F.X. if theres no "mono" option, and your custom music will be mono or missing half the sounds 😞
With mine I almost always lose the drums in the soundtrack. I thought it was just me.