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 Alchemy 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.
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.
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.
Download the guides:
Logic Pro User Guide: PDF