Alchemy partial envelope in Logic Pro for Mac

Source components are shown only in advanced view. Click the Advanced button to switch to advanced view, then click the A/B/C/D button to view detailed parameters for the selected source.

The source edit window is opened by clicking the Edit button on any source subpage. Click the close window icon (X) at the top right to close the window.

Use the Additive button at the top of the Main edit window to open the additive editor window.

The Partial envelope shows a number of points that indicate the temporal position of envelope snapshots (groups of partials) or individual partials, depending on the chosen Mode pop-up menu option (above the Partial bar). These points also indicate the overall level or value of the visible parameter type in the selected snapshot or partial. Partials are shown in the Partial bar display. See Alchemy partial bar display in Logic Pro for Mac.

Partial envelope parameters

Overall button: Shown above the Partial bar display, sets two Partial envelope modes.
- Overall button on: Each point represents a snapshot of summed amplitude, pitch, and pan values of all partials at a certain point in time. Typically, you choose snapshots in the envelope display and adjust individual or grouped partial values in the Partial bar display. You can, however, also adjust all partial values in a given snapshot by dragging vertically in the Partial envelope. The horizontal, or x-axis, indicates the temporal position of each snapshot. The vertical, or y-axis, indicates the summed value of each snapshot.
- Overall button off: Each point in the Partial envelope has a one-to-one correlation with the selected partial in the Partial bar display. Adjusting a value in either the Partial bar display or the Partial envelope is immediately reflected in the other. The horizontal, or x-axis, indicates the temporal position of the selected partial. The vertical, or y-axis, indicates the value of the selected partial.
  Note: The time positions of envelope points may vary from one partial to the next as you choose different partials when the Overall button is off. This is one of the keys to the high quality of resynthesis in Alchemy: each partial can have an independent set of points. When the Overall button is on, Alchemy presents a series of envelope points linked to all partials, and adjustments to individual partial times and values are handled automatically.
Detail knob: Set the resolution of the Partial envelope display. This affects the number of points shown.
- A value of 25% reduces the total number of visible points. This may necessitate scrolling or zooming to view all points.
- A value of 100% shows all points. The 500 or more visible points are unnecessary for anything other than the most precise edits, but you may find this level of detail useful when programming an additive sound from scratch, rather than editing resynthesis data.
Mode pop-up menu and field: Choose a mode to determine the way the envelope responds when a point is dragged.
- Normal: The dragged point only is moved. All other points remain stationary.
- Slide: Dragging one point causes all subsequent points to move, retaining the relative distances between points.
- Stretch: Dragging left compresses earlier points and stretches later points. Dragging right stretches earlier points and compresses later points. In either case, the total length of the envelope is preserved.
  Note: Point levels remain fixed in stretch mode, so you can only drag horizontally.
Partial envelope: Display and edit envelope point positions and values.
- The ruler indicates the current envelope position in milliseconds.
- The Partial envelope shows only straight line segments between points, with no convex or concave lines.
- The first and last points always have an amplitude of zero. In sounds with a fast attack phase, a second point with a nonzero amplitude is shown at a time position very close to the first point. You may need to increase the Detail setting to see the second point.
- Loop and warp markers can be superimposed on the Partial envelope. See Alchemy zone waveform editor in Logic Pro for Mac.
- Warp marker movements automatically snap to existing Partial envelope points.
- Positioning the loop start and loop end markers at identical positions creates a sustain point which allows a particular segment of the sound (a snapshot) to be heard continuously. This method is useful for locating, auditioning, and editing a succession of snapshots.
Scroll bar and zoom controls: Drag the middle of the scroll bar to view envelope points that are not visible in the display area. Horizontally drag the zoom controls at either end of the scroll bar to resize the contents of the visible display area.

Create or delete points in the partial envelope

In Alchemy in Logic Pro, do one of the following:

Click anywhere in the Partial envelope to create a new point for the active partial (selected in the Partial number bar).
Click on or near a line between existing points to create a new point.
When the Partial envelope contains existing points, either method creates a snapshot of partial values that fall in between the partial values associated with the preceding and following points.
If the Partial envelope is “blank” (only contains a single point), each newly-created point has a single associated partial value (for the partial selected in the Partial number bar). The partial (value) of the preceding point is also shown in the Partial bar display.
Note: The Overall button affects the display of values shown in the Partial bar and related points in the Partial envelope.
Double-click an envelope point to delete it.

Adjust partial pitch values with partial envelope points

When the additive editor displays pitch (the Tune button is on), point levels represent partial pitches. You can edit these levels to eliminate a pitch wobble or to create vibrato, for example.

In Alchemy in Logic Pro, click an envelope point to select it. You can also drag across multiple envelope points to select them.
This selects a snapshot of multiple partials when the Overall button is on, or individual partials when the Overall button is off.
When multiple points are selected, the Partial bar shows the average value of each partial across the selected envelope points. Edits of partial values are applied to all partials associated with the selected points.
Click the Tune button above the Partial bar display to view pitch values at the current envelope point.
If required, click the Mode pop-up menu above the Partial bar to choose how your edits are applied: to a single partial, all partials, or a group of related partials.
Drag the envelope point vertically to set the pitch value.
The time and pitch of the selected point are displayed at the pointer position when clicked.

Fix unwanted pitch fluctuations with copied envelope points

In cases where a resynthesized sound has unwanted pitch fluctuations, you can resolve these artifacts by reducing the PVar (pitch variation) control on the source A/B/C/D subpage. The downside with this approach is that each partial is aligned with its harmonic tuning which may change the character of the sound significantly. Try this alternative method.

In Alchemy in Logic Pro, make sure the Overall and Tune buttons are active, then select a single Partial envelope point.
Click the Breakpoint button, and choose Copy from Breakpoint from the pop-up menu.
Click the Breakpoint button, and choose Paste All Breakpoints Pitch Data from the pop-up menu.
The partial pitch values of the copied envelope point are applied to all other envelope points, thus retaining the inharmonic features of the copied point while simultaneously eliminating fluctuations from one point to the next.

Download the guides:

Logic Pro User Guide: PDF

Logic Pro Instruments: PDF

Logic Pro Effects: PDF

Helpful?

Logic Pro User Guide for Mac

Alchemy partial envelope in Logic Pro for Mac

Partial envelope parameters

Create or delete points in the partial envelope

Adjust partial pitch values with partial envelope points

Fix unwanted pitch fluctuations with copied envelope points