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Sequences

Across Atrium’s interface, you’ll find displays with light-glyphs consisting of 11 individual segments:

These indicate sequences, which can hold up to 11 steps of state information for their associated parameter. They are found near scale, shape, lens and drone. Tapping the key near these parameters selects a new set of data, which is why we refer to these keys as sequencers. sequences will wrap after the sequencer reaches its last stage.

In Atrium sequences all operate on complex data. Each stage contains a list of values too complex to perform in a live manner. These tiny systems enable us to expand the capabilities of the instrument, while asking the player to manage only a simple "next" gesture.

By default, each sequence is clamped by a small range, so as not to overwhelm with possibility. As you orient to Atrium’s system, you may desire more states to bounce between. Perhaps you want only a subset of those possibilities — there is significant joy to be uncovered in simply toggling between two meaningful states.

Refining & Extending sequences

All sequences contain one to eleven steps and can be 'windowed' to focus on any subset.

To change the length of any of the sequences:

  • Hold alt and press the sequencer key corresponding to any of the above-mentioned sequences. Each of the available options will be illuminated with a cross.
  • The extension display will now show an E, indicating that we are editing the selected sequence's bounds.
  • The selected sequencer will display the length of the sequence.
  • Press the octave keys to adjust the length of the sequence up or down.
  • Press alt to exit.
  • Now, presses to that sequencer key advances through the steps in our newly-defined length.

This is only half the story, though it is the most common usage. You can change the length of the sequence, as well as the start point. Thus we can begin counting from 2 or 3, not always 1. Furthermore, the value we edited above is not in fact the length, but rather it is the last stage of the sequence. Increasing the start will shorten the length!

  • Hold alt and press the sequencer you wish to edit.
  • Press the sequencer key again to toggle between start and last stage.
  • Note the lights beside the octave keys flip as you press the sequencer, indicating start (down) or last (up).
  • Press alt to exit.
  • Now, presses to that sequencer key advances through the steps in our newly-defined 'window'.

The start and last stages may be set to the same value, and these values will not be allowed to cross.

When editing sequences, you can change focus to another parameter by simply pressing another sequencer key — no need to exit & re-enter just to change focus.

Hexadecimal

The keen eye might notice that we can only display the numbers 0-9 on these small displays. As such we lean on the hexadecimal system to count the numbers 10 (A) and 11 (B). There's no greater meaning here, just a solution to a problem!

Initial States

The type of data in each sequence is unique for each parameter. Though their dedicated entries in the Player's Manual echoes a lot of the information which follows, it seems helpful to collect them all in one place.

Let's take a look at the initial states for each parameter's sequences in the template patch!

scale

scale defaults to four steps, which each contain a different pitch collection:

  1. C major
  2. A dorian
  3. D diminished lydian (roughly)
  4. G dorian (with C in the bass)

We can extend this sequence to access these additional pre-defined scales:

  1. C diminished 6th
  2. C major pentatonic (over a C bass pedal)
  3. C major pentatonic in 5-limit just intonation
  4. Sama Gana in C
  5. C lydian arpeggio (over two octaves)
  1. Bb major 7th arpeggio (with detune)
  2. C major 7th arpeggio (with detune)

One compositional technique is to use a small subset of this sequence to define different inversions of the same chord. For example, latch the scale sequence to simply swap between two steps. Set the notes in scale[1] and scale[2] to be nearly identical, except drop one of the notes by a fourth in scale[2]. Now, the scale button acts as a Drop 4 quick-action!

shape

shape defaults to four steps and changes the shape of the lfo:

  1. Ramp: rises smoothly, before sharply resetting to zero.
  2. Sine: a smooth up-and-down path with a natural feel.
  3. Triangle: a rigid up-and-down motion.
  4. Square: alternates between the high and low state.

We can extend this sequence to access these additional pre-defined shapes:

  1. Stepped Random: jumps to a new random value every cycle.
  2. Smooth Random: slides to a new random value over the course of each cycle.
  3. Crease: similar to Ramp, but resets half-way through the cycle and moves with bipolar motion.
  4. Sinc: A trigonometric function that smoothly rises once to full level, then a second time to a lower level.
  5. Pulse: Similar to Square, but is "high" for only 1/5th of the cycle.
  1. Scanner: Similar to Triangle, but compresses the motion to 2/5ths of the cycle.
  2. Bubbles: A jagged series of five rising ramps, each reaching higher than the last.

lens

lens defaults to five steps and cycles through different spectre filter placements:

format: v1 / v2 / v3

  1. 20% / 40% / 80%
  2. 40% / 50% / 60%
  3. 30% / 40% / 70%
  4. 50% / 60% / 70%
  5. 60% / 30% / 40%

We can extend this sequence to access these additional pre-defined placements:

  1. 70% / 10% / 20%
  2. 50% / 0% / 40%
  3. 30% / 40% / 20%
  4. 10% / 80% / 40%
  1. 20% / 60% / 50%
  2. 50% / 50% / 20%

drone

drone defaults to five steps and changes which voices are active:

  1. v1
  2. v2
  3. v3
  4. v4
  5. v5

We can extend this sequence to access these additional pre-defined voice pairs:

  1. v1 + v5
  2. v1 + v2
  3. v2 + v3
  4. v3 + v4
  1. v4 + v5
  2. v1 + v2 + v4 + v5