from a general space feng shui perspective I think South is the best location for your instrument, i.e. where you can place them, display them... etc.
Your best direction is NE - so if you're a musician, I would recommend you face NE. If you want to improve your skills I would recommend you face your personal growth direction.
Maybe you should check the Time Feng Shui, maybe you've been sitting in a location with less good feng shui.
Another good idea could be to write your activation cards and place them accordingly (with your music goals for example).
From my personal experience I would like to add that we often have resistance even to the things we love. So you could also let go of any resistance that might be there and also arrange the funiture in such a way that the flow of energy hits no resistance
When you're facing SW - do you also sit in a power position? (Back protected, door can be seen without turning the head?)