Arp
Alchemy offers a flexible and powerful Arpeggiator. To access it, click the ARP button in the Perform/Arp/Effects section towards the bottom of the interface. A large number of controls makes the Arpeggiator unusually versatile; but if you just want to create classic arpeggiator patterns, you’ll find this very easy to do. (In fact, you can probably skip straight to the Examples at the bottom of this page!)
The Arpeggiator sub-page consists of three main sets of controls. On the left is a series of nine knobs that control the basic behavior of the Arpeggiator. In the middle is a set of buttons, pop-up menus, and knobs that let you manage one or more Sequencers. These are called ‘Arp Sequencer’ modules, because they are internal to the Arpeggiator and separate from Alchemy’s normal Sequencers. On the right of the Arpeggiator subpage is a step editor for the Arp Sequencer modules. Below, you will find details about each of the basic sequencer controls, and an explanation of what the Arp Sequencer modules do. For more details about individual Arp Sequencer controls, see the explanation of the same controls on the page describing Alchemy’s normal Sequencers.
Basic controls
The basic Arpeggiator controls consist of nine knobs. Here’s what each of them does.
- Mode. Turns the Arpeggiator On and Off, and determines the order in which incoming notes are organized into a pattern. In addition to ‘Off’, you have the following choices:
- ‘Up’ plays the current notes from lowest to highest.
- ‘Down’ plays the current notes from highest to lowest.
- ‘Up/Down’ — lowest to highest and back again.
- ‘Down/Up’ — highest to lowest and back again.
- ‘As Played’ — plays the current notes in the order they were originally played.
- ‘Random’ — plays the current notes in a random, non-repeating order.
- ‘Chord’ — plays all of the current notes simultaneously as a chord. In this mode, the chords you play will ‘pulse’ according to the Arpeggiator’s rate and rhythm, as determined by the the Arp Sequencer settings.
Note: Like most knobs throughout the Alchemy interface, Mode is a mod target. In several of the factory presets, a Perform knob is set up to modulate Mode, so you can easily turn the Arpeggiator on and off during a performance.
- Latch. When Latch is Off, the current Arpeggiator pattern will stop playing when you lift your hands off the keyboard. When Latch set to ‘Hold’ or ‘Add’, the Arpeggiator ‘holds’ notes for you, so the current pattern will continue to play when you lift your hands off the keyboard. If you then play one or more new notes, two results are possible:
- In ‘Hold’ mode, the new notes are organized into a new pattern, which replaces the existing pattern.
- In ‘Add’ mode, the new notes are added to the existing pattern. (Try combining ‘As Played’ mode with the ‘Add’ latch setting to create an interactive step sequencer with up to 128 steps!)
- Amp. The Amp knob determines the velocity of notes played by the Arpeggiator (but see also the KeyVel knob). It can be modulated to create variations in note velocity as the Arpeggiator plays.
Note that Arp Sequencer 1 is assigned by default to modulate the Amp knob. Normally you should not remove this modulation assignment. Even if you don’t need the step values of Arp Sequencer 1 to determine the velocities of notes played by the Arpeggiator, this modulator plays a more fundamental role: the rising edge of each Arp Sequencer step is the Arpeggiator’s cue to play the next note in its current pattern.
- Tune. The Tune knob applies a pitch offset to all of the notes played by the Arpeggiator. For example, if you set Tune to 12 semitones, the Arpeggiator will play patterns an octave higher than the MIDI input. Tune is also available as a target to be modulated (e.g. by an Arp Sequencer). This allows you to create a variable pitch offset as the Arpeggiator plays.
- Pan sets a position in the stereo field for all the notes played by the Arpeggiator. It can be modulated to create variable panning as the Arpeggiator plays.
- Split. The keyboard can be split so that notes below a certain point are fed to the Arpeggiator, while notes above that point play normally. Split determines the highest note to be included in the Arpeggiator pattern; set it to the maximum value ‘g8’ to arpeggiate all of the MIDI input.
- KeyVel. Arp Sequencer 1 modulates the Arpeggiator’s Amp knob by default, and when KeyVel is 0%, the step values of Arp Sequencer 1 fully determine the velocities of notes in the Arpeggiator pattern. When KeyVel is 100%, these velocities are determined instead by the incoming MIDI data, so if you strike a key hard the corresponding note in the Arpeggiator pattern will have a high velocity level. You can also set KeyVel to intermediate values to blend the Arp Sequencer step values with the velocities in the incoming MIDI data.
- Octave determines whether the Arpeggiator pattern is played only at its original pitch level, or is repeated across additional higher octaves.
- Source. When Source is set to ‘All’, the Arpeggiator pattern is played by all sources (assuming they are all turned ON). You can also restrict the Arpeggiator pattern to any one source by setting this knob to a value of 1–4; then the other three sources will play the incoming MIDI data normally.
Note: When Source is set to a value other than ‘All’, so that one voice is arpeggiated while the others play normally, Alchemy uses separate voices to play the arpeggiated and non-arpeggiated portions of its output. Therefore, this feature requires the number of Voices to be set to at least 2 in the Master section.
Using the Arp Sequencer modules
Arp Sequencer modules work just like normal Sequencer modules in Alchemy. They have a more specialized job to do, however, because they are internal to the Arpeggiator and are designed to modulate its basic controls (which are described above).
Notice that if you right-click a knob in most sections of Alchemy (e.g. a Cutoff knob in the Main Filter section) and peek at the ‘Add Modulation’ options in the contextual menu, your choices include ‘Sequencer’. But if you right-click one of the Arpeggiator’s basic controls (e.g. its Pan knob), your choices include ‘Arp Sequencer’ instead.
By default, the Arpeggiator is configured with just one Arp Sequencer, and for most purposes this is all you will need. Arp Sequencer 1 modulates the Arpeggiator’s Amp parameter. This modulation assignment enables the Arpeggiator to ‘watch’ Arp Sequencer 1: whenever the Arpeggiator sees the rising edge of another Arp Sequencer step, it plays the next note of its own current pattern.
Various settings in the Arp Sequencer allow you to adjust the Arpeggiator’s behavior.
- StepDur. Choose a different ‘StepDur’ to make the Arpeggiator play faster or slower.
- Shuffle lets you create various ‘swing’ effects. Setting a Shuffle value greater than 0% increases the duration of the odd-numbered step (1, 3, 5, …) and decreases the length of the even-numbered steps correspondingly.
Note: For classic ‘swinging sixteenth notes’, set StepDur to 1/4 and try a Shuffle value of around 20% (light swing) to 30% (heavy swing). You can get more extreme effects using even higher Shuffle settings; at 100%, the even-numbered steps get so short that they disappear entirely!
- Sustain sets the length of each note played by the Arpeggiator, as a percentage of the StepDur. Lower values of Sustain will give you more ‘staccato’ results. (You may not hear a staccato effect, however, if your preset has a long release time.)
The Arpeggiator’s basic controls and the Arp Sequencer settings described above add up to a well-rounded Arpeggiator — one that can create a variety of patterns using notes played on the keyboard or other MIDI input, with controls in the Arp Sequencer for speed (StepDur) and rhythmic feel (Shuffle, Sustain). If you want even more options, you’ll find them in the Arp Sequencer step editor.
Using the Arp Sequencer step editors
When an Arp Sequencer modulates the Arpeggiator Amp, its step editor can be put to a number of uses. (Recall that Arp Sequencer 1 modulates Amp as part of the default configuration of the Arpeggiator.)
- You can edit the Arp Sequencer step values to create a pattern that the Arpeggiator will apply to the velocities of the notes it plays.
- If you set the value of a step to 0%, the Arpeggiator won’t play a note at that step. (There’s no ‘rising edge’ for the Arpeggiator to see when the step value is 0%; therefore it doesn’t trigger a note.) This creates a gap in the rhythmic pattern — a ‘rest’, in musical terms.
- Similarly, you can ‘tie’ one step to the next by shift-clicking below it. A small ‘chain-link’ symbol appears below each tied step. When two or more steps are tied together they behave like one longer step; only the first step triggers a note in the Arpeggiator, while subsequent tied steps provide sustain.
- You can edit the Arp Sequencer step lengths to create a pattern of shorter and longer note lengths. These values are combined with the overall note length determined by the Arp Sequencer Sustain control.
- You can edit the Arp Sequencer swing at each step to create subtle (or not-so-subtle) variations in timing. Each swing value ranges from 0 to 2; the middle value of 1 represents normal timing, while smaller values play earlier and larger values play later than normal. These swing values are combined with the overall timing pattern determined by the Arp Sequencer Shuffle control.
You can apply additional sets of Arp Sequencer steps to other basic controls in the Arpeggiator, such as Tune and Pan. Simply right-click on one of these knobs and choose ‘Add Modulation’ > ‘Arp Sequencer’ > ‘New Arp Sequencer’. (Indeed, that’s an early step in the example entitled ‘Creating a step sequencer’, found at the bottom of this page.)
Note that ‘New Arp Sequencer’ creates a new set of Value, Length, and Swing patterns that you can edit to suit your wishes; but all of the Arp Sequencer modules share a single set of controls such as StepDur, Shuffle, Sustain, Trigger status, and NumSt (number of steps). Alchemy’s normal Sequencer modules work differently: each one has an independent set of controls such as StepDur.
Importing from a MIDI file
Alchemy’s MIDI-import capabilities are described on the Sequencer page. The same Import Velocity, Import Note, and Import Groove commands are available here in the Arp Sequencer modules. An additional command, Import All is also provided; it sets step values in Arp Sequencer 1 based on extracted velocity data, sets swing values in Arp Sequencer 1 based on extracted groove data, sets step levels in Arp Sequencer 2 based on extracted note data, routes Arp Sequencer 1 to the Arpeggiator’s Amp knob with a depth of 100%, and routes Arp Sequencer 2 to the Arpeggiator’s Tune knob with a depth of 24 semis. The resulting configuration allows the Arpeggiator to play back the imported MIDI notes, velocities, and groove timing faithfully.
Example: Creating classic arpeggiator patterns
- Initialize Alchemy by clicking FILE in the Title bar and choosing ‘Clear’ from the pop-up menu.
- Switch the Perform/Arp/Effects section to Arp at the bottom of the interface, and play and hold a chord. Set Mode to ‘Up/Down’ and Latch to ‘Hold’. Now when you play a chord, it will be processed by the Arpeggiator, which continues to play when you release the chord.
- Next, as the Arpeggiator continues to play, you can explore additional Arpeggiator parameters:
- Try changing the Mode to a value other than ‘Up/Down’ — ‘Up’, ‘Down’, ‘Down/Up’, and ‘Chord’ are among the most popular additional Arpeggiator modes.
- Try setting Octave to a value greater than one in order to have the Arpeggiator pattern play in more than one octave range.
- Try changing the Arp Sequencer StepDur from its default value of ‘1/4’ to ‘1/2’ (so a note plays every half beat), to ‘1/8’ (eight notes per beat), and to other values. Restore a value of ‘1/4’ or greater before trying the next step.
- Experiment with the Arp Sequencer Shuffle and Sustain parameters.
- While the Arpeggiator continues to run, you can also adjust settings in other sections of the interface. For instance, try the following adjustments:
- Source A VA waveform = ‘Basic’ > ‘Square’; NOsc = 2.
- AHDSR 1: Decay = 0.50 sec; Sustain = 0%; Release 1.5 sec.
- Main Filter 1: Cutoff = 550 Hz; modulate Cutoff with AHDSR 1 (depth = 30%).
Example: Creating a step sequencer
- Initialize Alchemy by clicking FILE in the Title bar and choosing ‘Clear’ from the pop-up menu.
- Switch the Perform/Arp/Effects section to Arp at the bottom of the interface, and set Mode to ‘Up’ and Latch to ‘Hold’. Now play a single note and the Arpeggiator will play that same note repeatedly as you work through the rest of this example. (If this drives you crazy, set Latch to ‘Off’ instead!)
- Right-click on the Arpeggiator’s Tune knob and choose ‘Add Modulation’ > ‘Arp Sequencer’ > ‘New Arp Sequencer’.
- The Tune knob’s mod rack appears in Alchemy’s MOD section, and ‘Arp Sequencer 2’ can be seen in the first slot of the rack.
- Adjust the modulation Depth knob, to the right of this slot, to a value of 24 semitones in order to program a step pattern spanning two octaves.
- Returning to the Arpeggiator sub-page, set the ‘Snap’ value for the Arp Sequencer step editor to 1/24 in order to snap step values to semitones (since the modulation depth is 24 semitones).
- Ensure that the step editor view is set to Value (rather than Length or Swing, which are only useful when you’re modulating Amp). Now you can create a pattern of pitches by editing each step value as you desire.
Make it stop!!!
If the Arpeggiator keeps playing and you want it to stop, do one of the following things:
- Set the Arpeggiator Mode knob to ‘OFF’.
- Set the Arpeggiator Latch knob to ‘OFF’.
- Stop (or Play and then Stop) your host’s transport.