Random Magic Armor (any level)
(Self-revealing) valued at 18,350 gp.
Sonic Resistance Ability
A suit of armor or a shield with this enchantment normally has a glistening appearance. The armor absorbs the first 10 points of sonic damage per round that the wearer would normally take (similar to the Resist Energy spell).
Aura: Faint abjuration
Caster Level: 5th
Requirements: Craft Magic Arms and Armor, Resist Energy
Price: +18,000 gp.
Source: Dungeon Master's Guide v.3.5