: (1) A parameter on a synthesizer, effects unit, etc. which can be adjusted by the user to alter the mount of a particular effect, such as reverb, delay, or chorus.
(2) Effects Depth controllers. Controller Change messages which are used to implement the function described in Effects Depth. These were initially assigned to specific effects, but are now generalized and operate in conjunction with Effects Controls 1 & 2 messages; the two message types taken together are called Effects Control.