Possible Clues:

• Quavering note
• US band in Toledo removing editor's musical effect
• Lot more shaky -- this sound?
• Guitarist's effect gets lot more rocking
• Wavering — or lot more disrupted
• In strictly mistaken terminology blamed on Leo Fender, a guitar’s ____ arm is called a whammy bar
• Vibrating noise in shaky Metro line that’s old
• Fluctuation in pitch
• Unsteady effect could be lot more unsteady
• Effect of quavers on the score