Sonic (3.5e Equipment)
From D&D Wiki
Upon command, a sonic weapon is imbued with resonate energy. When struck against any surface a powerful sonic wave is issued forth. The sonic energy does not harm the wielder. The effect remains until another command is given. A sonic weapon deals an extra 1d6 points of sonic damage on a successful hit. Bows, crossbows, and slings so crafted bestow the sonic energy upon their ammunition.