Probably the most active server for music is Landroval. There's concerts nearly every night of the week in The Shire, and I'm sure there are some concerts in Bree and probably other places.
If you're free at 11pm EST on Wednesday evening or 10:30pm EST on Thursday, come check out the EMS show in Bree on Elendilmir / Michel Delving on Landroval (respectively.) We play a lot of music that is transcribed or even composed by our members, and we follow up with an Open Mic session where anybody can do solos/duets/trios/pretty much whatever.
Of course, there are a TON of different music groups there that will be happy to help you out. Hit me up on Thearo at our Landy show, and I can introduce you to a few different representatives of various groups.