SRD:Sonic Attack

Sonic Attacks (Su)
Unless otherwise noted, a sonic attack follows the rules for spreads. The range of the spread is measured from the creature using the sonic attack. Once a sonic attack has taken effect, deafening the subject or stopping its ears does not end the effect. Stopping one’s ears ahead of time allows opponents to avoid having to make saving throws against mind-affecting sonic attacks, but not other kinds of sonic attacks (such as those that deal damage). Stopping one’s ears is a full-round action and requires wax or other soundproof material to stuff into the ears.