VERY nice room! If it is backed up to Diamond head, must have nice views, mostly good weather, etc... Nice way to live!
For an audio-focused 'mancave', I think you'd have to add some acoustic treatments. It looks like it has some diffraction, but too much reflectivity. More carpets, perhaps some nicely-disguised acoustic material between those ceiling beams, some plants and disguised bass traps in the corners, perhaps a tapestry or two hanging by reflection points... But the "feel" of the room is very nice. :yes: :thmbsp: