So how many people play bards that actually use an instrument? Because of the hands being used to play the instrument, most people I've seen have focused on non instrument playing bards. So I came up with an Idea...
Sharp Instrument, Minor
Aura Minor Transmutation; CL 1st
Price 2000 gp; Weight Varies.
DESCRIPTION
By playing a sharp note on these instruments, any character with bardic music and ranks in the appropriate perform group can cause harm to those near them.
During a bardic performance, as a standard action, the wielder can attack an adjacent foe with a sharp sound from the instrument. The target makes a fortitude save equal to 10 + 1/2 of the appropriate perform skill ranks (including class bonus). Failure indicates that the target takes 1d6 points of sonic damage, success negates the attack. If the wielder has multiple attacks due to a high base attack bonus, the wielder can make additional sharp note attacks. Treat this in all other ways as if making an attack with a melee weapon.
Construction
Requirements Craft Wondrous Items, Sound burst; Cost 1,000 gp
Thoughts? Another way could be to make it a feat, but it seems a bit too supernatural for a feat, but it could work. Might think of a Major version later.