Retro Synth envelopes in Logic Pro for iPad

Retro Synth features two identical attack, decay, sustain, and release envelopes that shape the filter cutoff (ADSR - Filter section) and the level of the sound over time (ADSR - Amp section).

When you think of different sounds, such as a snare drum, piano, or strings, they’re not only tonally different, but the characteristics of the sound change over time. Both the snare drum and piano are heard immediately when struck. This is because they both have a short attack phase. Bowed strings, on the other hand, slowly ramp up in level—they have a long attack time, in other words.

If you break down any sound over time, you can emulate snare drum-like, piano-like, or string-like characteristics easily with Retro Synth envelopes.

Envelope parameters

Attack slider and field: Set the time it takes for the envelope to reach the initial level.
Note: Oscillators automatically switch from free mode to synced mode when the Attack time is set to values below 0.50 ms. This has a pronounced effect on stacked voices, in particular. See Retro Synth global and controller settings.
Decay slider and field: Set the time it takes for the envelope to fall to the sustain level, following the initial attack time.
Sustain slider and field: Set the sustain level, which is held until the key is released.
Release slider and field: Set the time it takes for the envelope to fall from the sustain level to a level of zero.
Velocity knob and field: Determine how sensitive the envelope is to incoming velocity.
- If the Velocity knob is set to zero, the envelope outputs its maximum level when you strike the keys at any velocity.
- At a Velocity knob value of 100%, the entire dynamic range is under velocity control.
  To explain, raising the Velocity knob value reduces the envelope minimum amplitude, with the difference being dynamically controlled by keyboard velocity. For example, when you set the Velocity knob to 25%, the minimum envelope amplitude is reduced to 75%. The remaining 25% is added in response to the velocities of keys you play. So, a key played with a zero velocity results in an envelope amplitude of 75%. A key played with a MIDI velocity value of 127 will result in an envelope amplitude of 100%. When you raise the Velocity knob value, the minimum amplitude decreases.

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Logic Pro User Guide for iPad

Retro Synth envelopes in Logic Pro for iPad

Envelope parameters