The modular system once developed by Robert "Bob" Moog went through a long production period between 1964 and 1981, including its development process. At that time, the new, electronic instrument was an avant-garde pioneering work that still had to be explained to the public, but ultimately found more and more interested parties.
The 911 Envelope Generator from Behringer is a classic ADSR envelope with the percussive amplitude curve familiar from the famous System-55. The control times for the three time phases can be set between 10ms and 10s.