If you have the defiant gear with instrument mods on it you don't have to use the instruments.

You are going to "fizzle" or have song errors till skill levels rise. Just as casters need to cast spells lots of times to raise skill levels, so do bards have to sing. The advantage is that you can set up training melodies that will keep casting your songs over and over all night. So, I made a melody that had:

/stopsong
/melody 7 8 5 3

8: Selos Rhythm of Speed (percussion)
7: Cantata of Soothing (Strings)
5: Agilmente's Aria of Eagles (Wind)
3: Denon's Disruptive Discord (Brass)

You can add one spells that is pure singing as well, likeVilla's Verses of Celerity (Singing).

NOW, the *REAL* trick to make this work is to find a place where the brass song will fire. And it turns out that there is a place that works like a charm. In Crescent Reach on the second floor there is the place where there is a bunch of dudes hitting on practice dummy's (also part of a quest). In the back of the hall there are some empty places where you can stand and fire this song and get skill ups. I got 38 in just a couple hours and was down to only fizzling (missed a note) once or twice per cycle.

I did this at level 41 and with one other full night of the basic set (exclusive of the brass) in Guild Lobby, I had most of the skills in 187 or higher (current cap is 210) ...

Good luck ...