Superb playing skill. Sounds like a great sounding instrument in a very reflective room.
Here's what I'd do (this is a messy solution though)... take everything out of your bedroom closet and hang it up against the walls of your recording space with picture hangers, ceiling hooks, mic stands w/booms, etc. Then move the mic just a little further away and see how the room sounds. It'll cut that HF sizzle down. I think I heard a couple lower midrange woofs in the room too, so if you can pile stuff up high in the corners it'll reduce that. Also, if you get the room to be not so reflective you can point the mic so that it's not aimed right at the instrument and it'll reduce the highs a bit, even with an omni. Not all mic's sound good that way though - some get phasey.
Is the mic an MSH-2?
Tim