music room floor design

This has probably been topical before but I havent quite found the info in other posts that I seek here. I have a floor in a 1st floor dedicated 7.5 x 4.2m music room, above a living room I can reconstruct to optimize audio performance. It is a wooden joist floor, plasterboard ceiling underneath, with a 20mm plywood floor (currently) and thats about it

The rough drawnig shows the basics. I am seeking guidance with insulation between joists and isolation between joists and plywood floor and this floor and a second better looking wood floor to go on top of that. Having said that the top floor can be made of anything really that "sounds good". As part of an overall objective, I will need to soundproof the room from below as much as possible

There will be some heavy horns and bass cabinets housed in this room. Please fire away...er, in a nice way preferably..

ps: my drawing has come out sideways and I'm not smart enough to fix it-sorry

Alan