How to get the ??? Song In Wall Market Karaoke Bar
Wall Market has a lot of different places to explore and discover, the city being a vibrant city unlike anything else in the game. Meanwhile, you will find a bar where you can enter with the karaoke going on. One of the side quests will also take you to this bar, so you'll definitely end up there if you do the side quests.
Almost right after entering the bar you will see a ??? on the screen that indicates you have a music track nearby that you can acquire. This one is really easy, because all you have to do is talk to the guy singing on stage and he will give you the music track "The Midgar Blues", which he says is his own song.
It would be way too easy and this guide wouldn't be of much interest, but this is not the song we are referring to. If you walk around the bar more and start to approach the kitchen, you will notice that a new piece of music starts playing and the ??? the icon appears again. You might think you could get this from one of the guys in the kitchen or people nearby, but you'll keep making it short.
The reason is that although you can hear the song in this part of the bar, the song itself is not actually located in the bar. Instead, it's located directly across that back kitchen wall. You can't just exit through a back door either, so head back outside and walk the streets to get to the area behind the bar using your map.
Once you get to the area behind the bar, you'll see a jukebox standing alone outside against the wall. Interact with the jukebox and you will receive the music track "Under the Rotting Pizza".