This chest spawns as you complete the Windsong Sanctuary raid "The Cacophony of Power" (see this quest entry for details).
Arc, Incisor
Cape of Clouds
Din, Breaker of Harmonies
Drape of Winds
Empowered Trophy of the Flowing Wind
Fidelity
Fold, Shield of Sound
Glowing Alaran Periapt
Greater Alaran Periapt
Harken, Proof
Leh, Sash of Oratory
Median Alaran Periapt
Ostentatious Armwraps of Ryken
Ostentatious Footwraps of Ryken
Ostentatious Handwraps of Ryken
Ostentatious Headdress of Ryken
Ostentatious Legwraps of Ryken
Ostentatious Stole of Ryken
Ostentatious Wristwraps of Ryken
Rebuttal, Ender of Arguments
Resounding, Mask of Echoes
Shifting Sphere of Veiled Ascension
Trophy of the Flowing Wind