Alchemy sequencer in Logic Pro for Mac

Modulation components are shown only in advanced view. Click the Advanced button to switch to advanced view.

The sequencer module is a programmable step-based modulator that can play patterns of up to 128 steps that are synchronized with the project tempo. The level of each step, groove/swing, and envelope can be controlled globally for the pattern and per step.

Figure. Modulation sequencer control panel.

Alchemy sequencer controls

Current sequencer pop-up menu and field: Access each Sequencer control panel by choosing a number from the pop-up menu or with the Previous and Next arrows. Alchemy provides up to 16 sequencers—one by default, but more if you create them when assigning modulators.
Trigger pop-up menu: Choose On to play the sequencer pattern from the beginning with each MIDI note-on. Off makes the sequencer run continuously. Voice On/FX Off modulates voice parameters only, not effects. The sequencer module is always synchronized with the Logic Pro tempo, regardless of the Trigger setting.
Note: Settings from earlier application versions may not behave as expected because of the additional trigger option. Change to VoiceOn/FX Off to match the former version behavior, then resave the setting.
Rate pop-up menu and field: Set the duration of every step in the sequencer pattern, expressed as a fraction of a beat. For example, assuming a quarter-note beat, a value of 1/2 produces eighth note steps and a value of 1/4 produces sixteenth note steps. You can also step through Rate values with the Previous and Next buttons (the arrows).
Value Snap pop-up menu and field: Quantize sequencer step values, limiting them to exact fractions of the available range. For example, a setting of 1/2 aligns bars to the values 0%, 50%, and 100% when dragged vertically. Off disables quantization, which lets you set step values freely. You can also step through available values with the Previous and Next buttons (the arrows).
Note: Value Snap doesn’t move existing step values into alignment with quantized positions; it only affects the response of step values when you move or create them in the step editor.
Edit Mode pop-up menu: Choose one of three edit modes. Your choice affects the appearance and behavior of the step editor to the right.
- Value: View and edit the value of each step in the pattern.
- Length: View and edit the length of each step in the pattern. Technically, you create a pattern of longer and shorter envelope shapes so that the attack, sustain (gate), and release stages fill a larger or smaller portion of the fixed step duration. These lengths are combined with the overall sequencer Attack/Gate/Release settings to determine the envelope shape of each step.
- Swing: Create variations in the timing of steps. Each swing value ranges from 0 to 2; the middle value of 1 represents standard timing, while smaller values play earlier and larger values play later. These swing values are combined with the overall sequencer timing pattern set with the Swing knob.
File button: Open a pop-up menu with sequencer-related commands.
- Preset submenu: Choose a preset sequencer configuration. This can be used as is, or as a starting point for your own sequences.
- Save: Store the current sequencer configuration (step values, lengths, and swing settings plus the sequencer control settings) in a new disk file (*.seq). The new sequence name appears at the bottom of the Preset submenu.
- Copy/Paste: Store the current sequencer configuration in the Clipboard. Paste applies the configuration currently found on the Clipboard.
- Clear: Reset the sequencer controls and pattern to default settings.
- Randomize: Apply random offsets to the Swing, Attack, Gate, and Release parameter values.
- Import: See the Import data from a MIDI file task in this section.
Swing knob: Adjust timing to create swing effects. Values over 0% increase the duration of odd-numbered steps (1, 3, 5, and so on) while decreasing even-numbered step lengths.
Attack knob: Set the time required for each step to reach its peak level.
Hold knob: Set the amount of time each step is held at its peak level.
Release knob: Set the time required for each step to fall from its peak level to zero.
Step editor: Shows steps numbered from left to right across the top of the display. Steps are represented by vertical bars that you can edit directly. The appearance and behavior of the step editor is determined by the active Edit Mode menu choice.
Scroll bar: Drag the middle of the scroll bar to view steps that are not visible in the display area.

Use the Alchemy sequencer step editor

In Alchemy in Logic Pro, the step editor shows steps numbered from left to right across the top of the display. The appearance and behavior of the step editor is determined by the active Edit Mode menu choice. In the default Value mode, for example, the value of each step is represented by a vertical bar. A blank column is shown when the value is zero.

Figure. Modulation sequencer step edit control panel.

Drag a bar vertically to adjust its value, or click directly at the required height.
Set the values of multiple bars by dragging horizontally across them.
Option-click a bar to set it to zero.
Tie one step to the next by clicking below it. A small chain-link symbol appears below each tied step. When two or more steps are tied together, they behave like one longer step.

Import data from a MIDI file into the Alchemy sequencer

Alchemy can extract information from a short MIDI file and can apply this information to patterns in the step editor.

You can extract velocity data and set step values to match. If the MIDI file consists of notes of equal duration, such as a succession of eighth or sixteenth notes, every step in the resulting pattern will have an associated non-zero value. If the MIDI file consists mainly of notes of equal duration with occasional gaps, such as a succession of eighth notes with occasional eighth rests, the gaps are represented by step values of zero. If the MIDI file has irregular timing, or if it consists of chords rather than single notes, the results of this process are less predictable and usually less useful.

You can extract groove data (timing inflections) and set step swing values to match. If the MIDI file consists of nearly equal durations, such as eighth notes or sixteenth notes with timing inflections, this process yields useful results.

You can also extract note pitch data and set step values to match. The MIDI file should consist of equal durations with no gaps and should be limited to single pitches between a low C and a C two octaves higher. For example, a MIDI file could consist of notes C1 through C3, with the low C corresponding to a step value of zero. Because the pitch range is always two octaves, you should use the sequencer to modulate pitch with a depth of 24 semitones in order to reproduce the pattern of notes in the original MIDI file.

In Alchemy in Logic Pro, choose one of the following Import commands from the Sequencer File pop-up menu.
- Import Velocity: Set step values based on extracted velocity data and swing values based on extracted groove data.
- Import Note: Set step values based on extracted note data and swing values based on extracted groove data.
- Import Groove: Set swing values based on extracted groove data.

Download the guides:

Logic Pro User Guide: PDF

Logic Pro Instruments: PDF

Logic Pro Effects: PDF

Control Surfaces Support Guide: PDF

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Logic Pro User Guide for Mac

Alchemy sequencer in Logic Pro for Mac

Alchemy sequencer controls

Use the Alchemy sequencer step editor

Import data from a MIDI file into the Alchemy sequencer