Alchemy additive element controls 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 select the source you want to edit.

The parameters in this section are shown when the Additive button is active in a source subpage. The additive element controls also include a number of additive effects. See Alchemy additive element effects in Logic Pro for Mac.

Additive element parameters

On/off button: Enable or disable the additive element in the source. This can be useful when an audio file has been imported using Add+Spec mode and both the additive and spectral engines are used to recreate different aspects of the sound. Use the on/off button to disable either section if you need to listen to the additive or spectral component in isolation.
Sine/Complex buttons: Use Sine to resynthesize each partial with a sine wave. Use Complex to choose a resynthesis waveform from the Shape pop-up menu.
Sine mode results in the most accurate resynthesis of the original sample and makes it easy to work with the additive effects and formant controls. In Complex mode, choosing any non-sine waveform can have a dramatic and often unusual effect on the overall timbre of the sound.
Note: The additive effects and formant controls are named on the assumption that each partial is a sine wave. If one of the complex waveforms is used, the Pulse/Saw knob and formant shape selectors behave in a more complex manner. To simplify working with these controls, it is recommended that the Sine option is chosen in most cases.
Shape pop-up menu: Choose a waveform used to resynthesize each partial in your sound.
Volume knob: Set the output level of the additive element within the source. When multiple elements are used in a source, use this control to set the relative level of the additive component.
Num Partials knob: Set the number of additive partials that are generated (up to 600).
The number of oscillators required depends on the sound. For example, a flute has a limited number of harmonics and requires fewer partials than a cello or a violin. The playable register can also affect the number of oscillators required: high notes will accommodate only a small number of higher harmonics before reaching the limits of audibility, while low bass notes may have hundreds of harmonics without reaching the limit. Alchemy automatically sets a suitable Num Partials value when re-synthesizing additive data from imported audio files. You can reduce this value in some cases, but removing higher partials can cause unwanted changes to certain sounds.
Note: The additive engine processes partials in groups of four. Set the Num Partials parameter to a multiple of four to achieve the best compromise between CPU load and sound quality. Always set Num Partials to the lowest number of partials that are required by the sound because this helps to reduce CPU load.
PVar knob: Tune all partials simultaneously. This occurs before processing by the additive effects modules which stretch/shift partial tunings. Set to 0% to tune all partials in a perfect harmonic series. Set to 100% to make each partial follow the pitch fluctuations detected in the original audio file. The sonic impact of this parameter is highly dependent on the audio material: sounds with strong inharmonic content such as bells are dramatically changed by reducing pitch variations. If all partials are tuned to the harmonic series, however, the knob has no influence on the sound.
The pitch variation knob is most useful when dealing with resynthesized audio. For example, if you analyze a vocal sample recorded with vibrato, this knob lets you reduce the vibrato depth, or remove it entirely with a setting of zero. Removing all pitch variations from a vocal can result in a synthetic, artificial character.
Sym knob: Alter the symmetry, or shape, of sine waves by lengthening the first half of the waveform while shortening the second, or the reverse. The audible effect is similar when the knob is turned in either direction. Symmetry alters waveforms until they are no longer pure sine waves in shape, resulting in each partial developing independent harmonics and making the sound brighter.

Resynthesize a sound and modify it with the main additive controls

In Alchemy in Logic Pro, click the File button in the Name bar and choose Initialize Preset from the pop-up menu to reset all Alchemy parameters to default settings.
Important: Use of Initialize Preset automatically turns on wide unison mode. See Alchemy wide unison mode.
Click a source select field, then choose Import Audio from the pop-up menu.
In the Import browser, click the Additive button to change the analysis mode.
Choose an audio file, then click Import.
Single notes with a strong harmonic character tend to work well. A good source of such files is the Vocals subfolder of the EXS Factory Samples folder.
Play the file up and down the keyboard and reduce the value of the Num Partials knob to remove upper harmonics. Note that when playing higher notes you will need to turn this knob down further before you hear it start to take effect.
Reduce the PVar knob value to remove all pitch variations and force all partials to a perfect harmonic series. A PVar value of zero completely removes any vibrato or pitch changes in the source sound.
Adjust the Sym knob value to change the symmetry of source sine waves, and note the extra brightness that is introduced by new harmonics that are generated.

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 additive element controls in Logic Pro for Mac

Additive element parameters

Resynthesize a sound and modify it with the main additive controls