Soul Adagio (魂のアダージョ, Tamashii no Adaajo) is a tehcnique used with Soul's Piano combined with Maka Albarn's Soul Perception ability and also derived from Arachne Gorgon's power.[1]
Overview
Working akin to noise cancelling, Soul's Piano can play a wavelength that is opposite of his target's own. When the opposing Wavelength or the "Antiphase Wavelength" reaches an opponent, it cancels out their abilities. This causes the target to be in a lethargic, trance-like state.[1]
Limitations
If an opponent has a stronger soul wavelength (in which means it generates more sound then the piano can handle), the technique can backfire and even damage the user.[2]