Alchemy granular 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 Granular button is active in a source subpage. The Granular section is available only when you import an audio sample using either granular or sampler mode. See Alchemy Import browser in Logic Pro for Mac.

Note: The sampler and granular engines are mutually exclusive: you can use one or the other within a single source, but not both together. You can, however, enable further sources if both engines are required simultaneously.

Granular synthesis represents continuous sound as a stream of grains, or tiny pieces of sound. Alchemy generates grains by extracting 2- to 230-millisecond pieces from an audio file. The amplitude of each grain is shaped, along with any pitch and pan modifications, before the grain is sent to the output stream.

Grains can be reordered, time stretched, and pitch shifted. This provides an inexhaustible supply of potential raw material to use as the basis of your sounds.

Granular element parameters

In addition to the following controls, granular playback is affected by loop modes and by the settings and modulations of the Position and Speed knobs in each source subpage. See Alchemy source subpage controls in Logic Pro for Mac. Modulations of the granular element update with each new grain. For an example of the impact this has, modulating the source Coarse Tune parameter with an LFO causes the stream of grains to rise and fall in pitch, but does not create pitch sweeps within each grain. If a large Size value is used in conjunction with a low Density value, modulations of source parameters such as pitch may sound stepped, rather than smooth.

Waveform window: Shows real-time changes to the waveform.
On/off button: Turn on to use the granular element in the source.
Volume knob: Set the volume of the granular element, independent of other source elements.
Size knob: Adjust the duration of each grain from 2 msec to 230 msec.
Density knob: Determine the number of potentially overlapping grains from 1 (no overlap) to 10.
The Size and Density parameters interact with each other. When the Density value is 1, a single grain is sent to the output stream. As soon as one grain finishes, the next one is sent. A Size value of 100 msec sends a new grain every 100 msec.
Increasing Density to 2 adds a second grain that is sent in between those of the first, resulting in a new grain every 50 msec, assuming a Size value of 100 msec. The first and second grains overlap each other. Higher Density values inject additional new grains into the output stream. These new grains occur more frequently and overlap more heavily.
Setting Size to around 100 msec and Density to around 5 grains is often suitable for smooth pad sounds with no sharp transients. Setting Size between 40 and 80 msec and Density to around 2 grains is useful for drums and other sounds featuring sharp transients. Small Size values tend to produce a buzz that masks the original pitch of the sample. Large Size values tend to break up the sound. You can counteract both tendencies by increasing the Density.
Note: Also important to the Size and Density parameters is the shape chosen in the Grain Shape pop-up menu. This can have a significant or subtle impact on sonic artifacts that may be introduced in the stream of grains.
RTime knob: Add a small random offset to grain extraction positions in the sample. The default value is 3% because a small amount of randomization helps to smooth the output of the granular element.
RPan knob: Add a random offset to the stereo position of each grain. The source Stereo button must be on for RPan to have an effect.
Num Taps knob: Set the number of taps (up to 8). Taps retrigger the attack phase of the source.
Note: Taps that fall within a looped area are retriggered on each loop cycle.
Tap Spacing knob: Set the spacing between the specified number of taps. Values are shown as a percentage of the overall sound duration. Set to 100% to evenly space taps across the entire sound duration. Set to 50% to trigger more closely spaced taps that start at the halfway point of the sound. Set to zero to trigger taps in quick succession at the sound end point.
Stereo Offset knob: Offset the stereo position to create a wider sound. The source Stereo button must be on for Stereo Offset to have an effect.
Grain Shape pop-up menu and field: Choose the envelope shape that is applied to each grain. At a basic level, this applies a small fade-in and fade-out to each grain, but some shapes may have a more significant impact, depending on the current Size and Density values (and the source material). You can also step through the available grain shapes with the Previous and Next buttons (the arrows).
This function is primarily intended to reduce or remove glitches, clicks, and crackles in the playback of a stream of grains, but it can introduce buzzy gaps between grains and can affect the tonality of grains. The effect of the chosen grain shape can also be quite subtle in many cases, particularly when you avoid extreme Size and/or Density values. There are no fixed rules when it comes to the choice of grain shape, given the infinite variety of source audio material. Therefore, you may want to experiment to achieve the required results.

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Alchemy granular element controls in Logic Pro for Mac

Granular element parameters