The AGateR, ADSR, and GateR buttons in the Amplifier section determine which of the ADSR envelope controls affect the amplifier envelope. All ADSR parameters remain active for the filter.
The letters A, D, S, and R refer to the attack, decay, sustain, and release phases of the envelope (see ES1 envelope parameters overview).
Gate refers to a control signal used in analog synthesizers that is sent to an envelope generator when a key is pressed. As long as an analog synthesizer key is pressed, the gate signal maintains a constant voltage. When Gate is used as a modulation source in the voltage-controlled amplifier (instead of the envelope), it creates an organ-type envelope without any attack, decay, or release phase—in other words, an even, sustained sound.
The ES1 amplifier envelope mode buttons affect played notes in different ways.
AGateR: In this mode, move the Attack and Release sliders of the ADSR envelope to set these phases of the sound. Between these phases, the Gate control signal maintains a constant level while a note is held. When you release the key, the release phase begins immediately. The Decay and Sustain sliders of the ADSR Envelope have no impact on the sound level.
ADSR: Set this mode to control the level of the sound over time with the ADSR envelope.
GateR: In this mode, the Gate control signal maintains a constant level while a note is held. As soon as you release the key, the release phase begins. The Attack, Decay, and Sustain sliders of the ADSR Envelope have no impact on the sound level.