State Machines & the Erica Polivoks Envelope II How would you describe an ADSR circuit? To borrow a term from programming (and more specifically, computational modelling), ADSR envelopes are state machines. They have a  finite number of states, and each state is able to transition to other states based on inputs or events. To make this useful, each state will also generally have some other impact—in this case, on the overall output level of the envelope generator. I think of ADSRs as having 3 to 5 states: <...