Logic Pro Alchemy partial bar display

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 edit window.

The Partial bar display shows up to 600 partials with independent amplitude, pitch, pan, and phase values at each Partial envelope point. You can edit individual partials or groups of related partials for each envelope point.

Note: Higher partials that are part of the additive data set may not be heard unless the Num Partials (number of partials) control on the respective source A/B/C/D subpage is set to a suitably high value. For example, raising the amplitude of partial number 72 has no effect when Num Partials is set to a value of 60. Conversely, setting a Num Partials value of 500 has no effect in additive mode unless partial data exists for 500 partials.

Partial bar display parameters

Overall button: Use in conjunction with the Vol, Tune, Pan, and Phase buttons to display partial values averaged across all envelope points. When the Phase button is active, the Partial envelope only is updated.
Turn on Overall to adjust the amplitude, pitch, and pan values of all partials across the entire sound, without the need to select and edit individual envelope points for each partial. Also see the Overall button information for the Logic Pro Alchemy partial envelope.
Partial display mode buttons: Click Vol, Tune, Pan, or Phase to restrict the display to the chosen partial parameter type.
- Vol button: Show partial amplitude values.
- Tune button: Show partial pitch values. Also see Snap Pitch button information below.
- Pan button: Show partial pan values.
- Phase button: Show partial phase values.
Mode pop-up menu and field: Choose a group of related partials for editing. You can also click the Previous and Next buttons (the arrows) to step through modes. Group adjustments retain the relative differences between partial values. Hold down Command while dragging to scale adjustments logarithmically. Note that the Shape pop-up menu affects editing behavior in each mode.
- One: Adjustments affect the value of only the selected partial.
- All: Adjustments affect the values of all partials.
- Even: Adjustments affect the values of only even-numbered partials.
- Fifths: Adjustments affect the values of only partials that are fifths apart from the selected partial and the selected partial itself.
- Octaves: Adjustments affect the values of only partials that are octaves apart from the selected partial and the selected partial itself.
- Odd: Adjustments affect the values of only odd-numbered partials.
- Thirds: Adjustments affect the values of only partials that are thirds apart from the selected partial and the selected partial itself.
Shape pop-up menu and field: Choose a weighted group of related partials for editing.
- Normal: Adjustments affect only the selected partial and grouped partials that precede it.
- Flat: Adjustments evenly affect all grouped partials.
- Bright: Adjustments are weighted toward higher grouped partials.
- Dark: Adjustments are weighted toward lower grouped partials.
Snap Pitch button: Visible only when the Tune button is active. Automatically limits partial pitch values to meaningful units when a bar is edited.
Breakpoint button: Open a pop-up menu with a number of Partial envelope point-related commands. See Logic Pro Alchemy partial envelope.
- Copy Breakpoints: Copy all partial data in the currently selected envelope point or points to the Clipboard.
- Paste Breakpoints: Paste all partial data from the Clipboard to the currently selected envelope point or points.
- Paste Breakpoints Amp/Pitch/Pan Data: Paste the currently visible parameter partial data from the Clipboard to the currently selected envelope point or points.
- Paste All Breakpoints Amp/Pitch/Pan Data: Paste the currently visible parameter partial data from the Clipboard to every envelope point.
Image button: Open an import dialog where you can choose a PNG format image file for conversion to additive synthesis data. See the task in this section.
Clear button: Removes all partials and resets the Partial bar display and Partial envelope to default values.
Partial bar display: Shows editable bars that represent partial values.
Partial number bar: Indicates the selected partial. Click a partial number to select it without affecting any values.
Scroll bar and zoom controls: Drag the middle of the scroll bar to view partials 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.

Adjust the values of one or more partials

In Logic Pro, from the Partial bar display, do any of the following:

Click directly at a position in a bar to set a value.
Drag a bar vertically. Hold down Shift while dragging to set values with enhanced precision.
Drag horizontally to create multiple new partials or to alter several existing partial values.
Control-click a partial or drag a partial below the baseline to set it to a value of zero.
Control-click in the Partial bar display, then drag left or right to set multiple partials to a value of zero.

Create an additive sound from scratch

This example introduces the basic principles of additive programming in Alchemy.

When you create a new, initialized preset by choosing Initialize Preset from the File button pop-up menu in the Name bar, source A is in VA mode.

For additive synthesis, a different default configuration is better suited. It is not necessary to change any settings from their initial values as soon as you enter the Additive edit window and start creating data; the configuration of source A switches, automatically, to a sensible set of defaults for additive programming.

In Logic Pro, open advanced view and click the A button to view the source A subpage, then click the source A Edit button to open the Main edit window. Click the Additive button at the top of the Main edit window to view the Additive edit window.
Set the Detail knob to 100% for an accurate view of all data.
Make sure the Partial bar display Vol button is on and the Overall button is off.
Drag from left to right in the Partial bar display to draw in bars that define the harmonic content at the beginning of the sound.
Play a few notes on your MIDI controller to confirm that the sound begins with a bright timbre.
The default loop mode is Continuous which loops the sound indefinitely when you hold a note. If you do not want the sound to loop, change the Loop mode to None.
Select point 2 in the Partial envelope, then click the Breakpoint button and choose Copy Breakpoint from the pop-up menu.
Select point 3 in the Partial envelope, and drag it toward point 2. Release point 3 when you are close to point 2.
Click the Breakpoint button, and choose Paste Breakpoint from the pop-up menu. Make sure point 3 is selected.
The data from point 2 is copied to point 3, smoothing out the levels between points.
Click the X icon at the top right to close the Additive edit window.
The Additive element parameters are displayed.
Experiment with the Additive parameters to change the tone of your basic additive sound. Feel free to use other synthesis, filter, modulation, and effect parameters to make your additive sound more interesting.

Import an image file, and convert it to additive data

Alchemy is capable of importing an image in PNG (Portable Network Graphics) format and translating it into additive synthesis data. You can convert an existing image into sound, or you can design new sounds by drawing the image you want to import in an external graphics application.

In Logic Pro, open advanced view and click the A button to view the source A subpage, then click the source A Edit button to open the Main edit window. Click the Additive button at the top of the Main edit window to view the Additive edit window.
Click the Image button at the top right of the Additive edit window, then choose a PNG-format file in the file browser.
The selected file is translated into additive data using the criteria outlined below.
- Each column of pixels represents a snapshot in the additive data. The leftmost column describes snapshot 1, the next column to the right describes snapshot 2, and so on. Snapshots are timed at a steady rate of 20 per second.
- Within each column, there is a one-to-one correspondence between pixels and partials: the bottom row represents partial 1, the second row up represents partial 2, and so on. Thus the height of your image determines the number of partials. For example, an image 100 pixels tall translates to a 100-partial sound.
- The brightness of each pixel determines the amplitude of a particular partial in a particular snapshot. A black pixel corresponds to silence, while a white pixel corresponds to maximum amplitude. You can import both color and grayscale images. Color information other than brightness is ignored.
  Note: Importing an image with a lot of bright pixels results in additive data with numerous high-amplitude partials, which may cause clipping to occur.
If the results of an image import are unexpectedly noisy, you can reduce the overall amplitude by doing one or more of the following:
- Reduce the Vol setting of the additive element.
- Click the Overall button, then choose All from the Mode pop-up menu, and drag downward in the Partial bar display.
- Use your graphics software to darken the image before importing it.

Helpful?

Logic Pro User Guide

Logic Pro Alchemy partial bar display

Partial bar display parameters

Adjust the values of one or more partials

Create an additive sound from scratch

Import an image file, and convert it to additive data