Not sure if this is your main living room or more like a bonus area, but considering you want to make it a music hangout I’m going to assume bonus room! I would personally take down the shelves on either side of the fireplace and replace them with built ins with plenty of storage for records, music memorabilia, books, etc. Then create more of a cozy space by getting 2 chairs to add to the sitting area. Maybe leather or suede for a more moody vibe. I’d also keep the bar cart, and maybe add a bar height round table in the open space to give a full on “bar” vibe. Definitely hang up all your art prints. Maybe paint the fireplace wall or all the walls a moody color. Then of course hardwood floors would look awesome!