In the group I am DMing there is a bard (level 1), who wants to use the countersong supernatural ability.
As far as I understand, it is a defense against audible attacks by an enemy. And the countersong can help the bard's allies.

But I am interested in what specific attacks can be defended against? Any wizard spells that have an audible verbal component? A shouting barbarian trying to [intimidate][1] the group during battle? Or just things like "[ghost sound][2]" which produce a sound effect where you can do a will save (for disbelief)?

And _when_ can the bard start the performance? As soon as the enemy does the attack? Or just when it's the bard's initiative turn? How would that help his allies (so they can use his performance check instead of their saving roll)?

As you see, I'm quite confused about this supernatural ability, and the [docs][3] didn't help me much either.


  [1]: http://www.d20pfsrd.com/skills/intimidate
  [2]: http://www.d20pfsrd.com/magic/all-spells/g/ghost-sound
  [3]: http://www.d20pfsrd.com/classes/core-classes/bard#TOC-Bardic-Performance