Source
Alchemy’s sound-generating modules are called Sources.
There are four Sources available in an Alchemy preset (A, B, C, and D). Each Source is made up of an identical set of components:
The four Sources are entirely independent of one another, and can contribute to the overall sound in very different ways.
Elements
Each Source provides three sound-generating elements based on different methods of synthesis:
- An Additive element, which can also be operated in virtual analog (VA) mode.
- A Spectral element, which can also be used as a raw white and filtered noise source.
- A Granular element, which can also be used for conventional sample playback (Sampler mode).
These can be toggled on or off independently, the only restriction being that when the Granular element is on, the Additive element can only be used in VA mode and the Spectral element can only be used as a noise source. To combine synthesis methods without facing this restriction, you can use multiple Sources.
Source filters
The Source filter module provides three multi-mode filters, which can be configured either in series or in parallel. The Source filters allow you to filter each Source independently from the others. (Compare the Main filters, which process a mixture of all four Sources.)
With the Source filters in series the signal passes through the three filters one after the other, like this:
With the Source filters in parallel the signal is split and fed through the three filters simultaneously, like this:
Note: When the filter configuration is parallel and each filter is set to the ‘Formant’ type, a variety of Formant filter effects can be produced. See the example at the bottom of the Filter page for details.
FilterMix
The FilterMix control works like a kind of two-channel mixer (more accurately, a crossfader).
- With the FilterMix control turned all the way to the left, all of the Source’s output is fed to Main filter 1, and none of it to Main filter 2. (When you set the FilterMix knob this way, the parameter value display reads ‘100% F1 0% F2’.)
- With the FilterMix control turned all tthe way to the right, all of the Source’s output is fed to Main filter 2, and none of it to Main filter 1. (When you set the FilterMix knob this way, the parameter value display reads ‘0% F1 100% F2’.)
- With the FilterMix control set half-way, equal amounts of signal are sent to Main filters 1 and 2. (When you set the FilterMix knob this way, the parameter value display reads ‘50% F1 50% F2’.)
Global page controls
At the top of the Global page’s SOURCE section are five buttons: ALL, A, B, C, and D.
When the ALL button is illuminated, the Source master controls are displayed.
When the A, B, C, or D button is activated, the Source sub-page controls for the selected Source are displayed.
Source master controls
The Source master controls are a basic set of controls, duplicated for each of Alchemy’s four Sources. These are a subset of the controls accessible from each Source sub-page.
- On/off button (labelled ‘A’, ‘B’, ‘C’, ‘D’). Toggles the selected source on or off.
- Source content selection field. Displays the name of the current Source audio data. Clicking the field opens a pop-up menu with the following commands:
- Load Audio — Quickly imports audio data (WAV, AIFF, or SFZ) into the Granular element, for playback in Granular or ordinary Sampler mode. Turns the Granular element on and the other elements off. If a SFZ file includes filter settings, configures a Source filter accordingly.
- Load VA — Quickly loads waveform data into the Additive element, for playback in VA mode. Turns the Additive element on and the other elements off.
- Import Audio — Opens a browser window for previewing sample data and importing it into the Granular, Additive, or Spectral elements. (See the Import page for details.)
- Load Source and Save Source — Loads Source data from disk and writes it to disk. Uses special SRC file format. Loaded/saved data includes settings of all Source controls and a reference to loaded/imported audio data. (Source control modulations are not loaded/saved as part of the SRC file.)
- Copy Source, Paste Source — Copies Source data to the clipboard and pastes it from the clipboard. Useful for duplicating the content and settings of one Source in another. Copied/pasted data includes settings of all Source controls and a reference to loaded/imported audio data. (Source control modulations are copied/pasted as part of the clipboard data.)
- Randomize Source — Applies random variations to relevant Source controls, depending on which elements are active in the Source.
- The Load Additive/Spectral and Save Additive/Spectral commands are described on a separate page — Additive and Spectral data: AAZ and CSV files.
- Amp adjusts the level of the Source’s output (–inf dB to 0 dB).
- Tune adjusts the level of the Source’s output, in semitone increments.
Note that a Fine Tune control is available on each Source sub-page.
- Pan positions the Source’s output in the stereo field. (It works as a pan control if the source STEREO button is off, and as a left/right balance control if the source STEREO button is on.)
- FiltMix controls the routing of the Source output to main Filters 1 and/or 2, as described above.
- The MORPH controls (pop-up menu, X and Y knobs) are described on their own page.
Source sub-page controls
Each of Alchemy’s four sources has an identical set of controls for more in-depth editing.
Several of the Source sub-page controls are duplicates of those found on the Source master panel. These include the On/off button, the Source content selection field, and controls for Amp, Coarse Tune (corresponds to ‘Tune’ on the master panel), Pan, and FiltMix. See details in the discussion of the Source master controls, above.
Each Source sub-page offers also offers several additional controls:
- The Loop mode selection field contains a pop-up menu with five choices:
- None — Ignores the loop start and end points, and plays the entire sound once without looping.
- Continuous — Plays from the beginning, enters the loop region, loops continuously in a forward direction while a note is played, and goes on looping during the release stage.
- Sustain —Plays from the beginning, enters the loop region, loops continuously while a note is played, and exits the loop region to play the remainder of the sound during the release stage.
- Forward/Back —Like Continuous, but plays the loop region alternately forward and backward. If jumping from the end of the loop region back to its beginning produces an unwanted discontinuity, Forward/Back mode may give you more continuous results.
- All —Ignores the loop start and end points and loops the entire sound continuously.
Note. The loop start and loop end points can be edited in the Main view of the Source edit page. The Additive element in VA mode, and the Spectral element in WHITENOISE mode, use raw oscillators and noise sources rather than loopable data, so elements using these types of synthesis are not affected by the Loop mode setting.
- Solo button. When lit, isolates the Source by turning off all the other sources. Click again to restore the normal on/off status of other Sources.
Note. If you save a preset with one Source in Solo mode, the result is a preset in which that one Source is on (but no longer in Solo mode) and the other Sources are off.
- Edit button. Gives you access to the Source edit page.
- The KTRACK selection field contains a pop-up menu with three choices:
- Key+PBend — The pitch of the Source responds normally to MIDI Note data and PitchBend data.
- Key — The pitch of the Source responds normally to MIDI Note data but does not respond to PitchBend data.
- Off — The pitch of the Source does not respond to either MIDI Note data or PitchBend data.
Note that the ‘normal’ response to PitchBend is set via the PitchBend Up and Down controls in Alchemy’s Master section.
- Stereo button. Toggles stereo mode. If stereo mode is off and a stereo file is loaded/imported, only the left channel will be played. When stereo mode is on, loaded/imported sounds are played in stereo and various manipulations such as panning individual oscillators in the Additive element and panning individual grains in the Granular element are possible. (See the Additive and Granular pages for details.)
- Fine Tune adjusts the Source pitch in increments of one cent (one hundredth of a semitone).
- Position. Determines the position within the audio data from which playback starts. (0% = very start of data, 100% = very end.) See ‘Modulating Position’ below for more information.
- Stretch. In Additive, Spectral, or Granular mode, the Stretch setting determines the rate at which playback travels through the audio data. A setting of 100% represents the original playback rate. Higher settings (up to 500%) represent faster playback, while lower settings (down to 0%) represent slower playback.
- Playback remains at the normal pitch regardless of the rate of travel.
- Playback begins at Position and travels through the audio data on a path determined by the Loop mode. The Stretch setting determines the rate of this travel. (However, see ‘Modulating Position’ below for an alternative way to control the playback rate and path.)
- Setting Stretch to 0% ‘freezes’ playback at the position determined by Position.
- Stretch has no effect when the Granular element is set to ordinary Sampler mode.
Modulating Position
Position is a modulation target, which means you can control the path of playback through the audio data with a modulator.
- In the Granular element’s ordinary Sampler mode, the modulation value at the Note-On moment determines an initial offset for the play position. Beginning at that position, the rest of the sound plays in a normal manner, but looped as if the Loop mode were set to ‘All’.
- In Additive, Spectral, or Granular mode, Position can be continuously modulated.
- Try setting Position and Stretch to 0% and modulating Position with a unipolar LFO, an MSEG, or a Perform control linked to the modwheel.
- When Position is modulated and Stretch has a value greater than zero, the playback path is determined by a combination of the modulation value (whenever this value changes) and the ‘normal’ path (travelled at a rate determined by Stretch whenever the modulation value is static).
The example at the bottom of this page illustrates how to use modulation of the Position value to create a tempo-synced loop.
Elements and filters
A further four sub-pages are accessible from the bottom of each Source sub-page, which contain controls for the Source’s elements and its Source filters.
For information on the element controls, see the Additive, Virtual Analog (VA), Spectral, and Granular pages.
The Source filters are described above. For details on filter types and filter controls, see the Filter page.
Example: Tempo-synced loops
Synchronizing playback of looped audio with the host tempo is easy to achieve by modulating the Position parameter appropriately. This technique is possible with any synthesis method in Alchemy that permits continuous modulation of Position. In the example below, we use the Granular engine, but the same technique can be applied to the Additive and Spectral engines.
- Initialize Alchemy by choosing the ‘Clear’ command in the Title bar’s FILE menu.
- Load (into Source A) a rhythmic or melodic sample that works well when looped. Try ‘Factory’ > ‘Loops’ > ‘DrumLoops’ > ‘Cyborg-4bts.wav’. (The Load command imports this audio file quickly into the Granular engine. You could also Import the file, using any import mode, and the technique presented here would work fine.)
- Now if you play and hold C3, the ‘Cyborg-4bts’ sample will play in a looped fashion. (Note that the Loop mode is already set to ‘Continuous’ by default.) If your host tempo happens to be 120 BPM, the loop will stay in tempo reasonably well — but suppose you want to sync the loop automatically to a different tempo set in your host.
- Turn the Source A Stretch knob down to its minimum value of 0%. Now if you play notes you’ll find that playback is frozen at the very beginning of the sample. (All you’ll hear is a low rumble, because all of the individual grains are being drawn from the low bass sound that begins the sample.)
- Next we’ll assign a modulator to the Position parameter in order to control a playback path through the audio data. First we want the Position to increase smoothly so that the entire sample plays back from beginning to end, then we want the Position to jump immediately back to the beginning, and finally we want to repeat this path so that the sound loops. The right modulator for this job is an LFO with a ramp up shape. Click the Position knob in order to access its mod rack in the Modulation section. In the first mod rack slot, choose LFO 1, which brings the LFO 1 controls into view on the right-hand side of the Modulation section. Finally, choose ‘RampUp’ in the LFO Shape selection field and turn off the BIPOLAR button.
- If you play and hold a note now, you’ll find that the sample is looping as required, but the playback speed is much too fast. As its name suggests, the ‘Cyborg-4bts’ sample has a length of four beats. At its default rate, LFO 1 completes a cycle every beat. Adjust the LFO Rate to ‘4 beats’. Play and hold another note to confirm that the playback speed is now correct.
- Finally, adjust your host tempo as you play additional notes to confirm that the loop is properly synchronized with the host tempo.
To summarize what’s happening in this result: a tempo-synced LFO with a ramp up shape is controlling the Position knob, which causes playback to scan through the audio data in a forward direction every four beats. The result is a tempo-synced loop. The diagram below depicts these relationships.
Note that it’s not actually necessary to ‘freeze’ the playback by setting Stretch to 0%, as we’ve done in step 4, before modulating Position. The LFO shape we’ve chosen (ramp up) is constantly changing, without any static/flat portions; this means that it always controls play position, which makes the value of Stretch irrelevant. (Try double-clicking Stretch to restore its default 100% value. Then play a note: the looping behavior remains the same.) However, if we were to use a different LFO shape with static/flat portions, then setting Stretch to a non-zero value would cause play position to be controlled by a combination of the LFO shape and the normal play behavior of the sample. (Try changing the LFO shape to ‘RandHold’ — the results may be more musically interesting if you also increase the LFO rate to ‘1/2 beats’. Then play notes and compare the results you get with Stretch set to 0% versus 100%.)