Reverberation

(Savage Species, page 39, DnD 3.0)

[General]

Your sonic attack is more potent than normal.

Prerequisite

Sonic special attack

Benefit

Add +2 to the DC of all saving throws against your sonic attack.

Special

If you have more than one form of sonic attack, you can take this feat multiple times. Each time, it applies to a different one of your sonic attacks.