Countersong

While Obsidian has not confirmed the existence of countersong in NWN2, it is a class feature of the bard class which have been confirmed.

3.5 Countersong
This is a form of bardic music.

A bard with 3 or more ranks in a perform skill can use his music or poetics to counter magical effects that depend on sound (but not spells that simply have verbal components). Each round of the countersong, he makes a perform check. Any creature within 30 feet of the bard (including the bard himself ) that is affected by a sonic or language-dependent magical attack may use the bard’s perform check result in place of its saving throw if, after the saving throw is rolled, the perform check result proves to be higher. If a creature within range of the countersong is already under the effect of a non-instantaneous sonic or language-dependent magical attack, it gains another saving throw against the effect each round it hears the countersong, but it must use the bard’s perform check result for the save. Countersong has no effect against effects that don’t allow saves.

Duration
The bard may keep up the countersong for 10 rounds.