Bardic Music underwater?

[Percivellian]

From the Freedom of Movement entry in the SRD:

The spell also allows the subject to move and attack normally while underwater, even with slashing weapons such as axes and swords or with bludgeoning weapons such as flails, hammers, and maces, provided that the weapon is wielded in the hand rather than hurled. The freedom of movement spell does not, however, allow water breathing. (emphasis added).

Only water breathing or a necklace of adaptation should work.