Mapping

As you play through the many nooks and crannies of Atrium, you may wish for extra hands. Atrium can easily integrate many sources of modulation, both internal and external, to extend your articulations and deepen your explorations.

Mapping is the connection of sources to destinations (aka paramaters). In other synthesizers this is often called a "modulation matrix", or in a modular synth, these are the cables that string together a patch. Atrium allows every modulator to control any number of parameters, and any parameter can be modulated by any number of sources. Each of these mappings has an intensity, allowing remote-control to be dramatic, or extremely subtle.

The gateway to mapping is the big peachy-coloured map key (illustrated above), and you'll see corresponding italicized text around the interface to match. These markings indicate Atrium's mapping sources which you'll be needing shortly...

Mechanics

The general process of creating a mapping is:

Press & hold map to display all of the available sources. Lights will be near each associated key with a peach backdrop.
Select the source by pressing the source's key.
Once a source is selected, you can release map.

You're now viewing all the mappings associated to the selected source.

Move the destination parameter to define the depth of modulation you’d like to apply. You can map any source to multiple destinations at the same time. We encourage you to start small, as its so lovely to have a little modulation animating many controls versus applying ‘an LFO effect’.
Lights on the interface will indicate the depth of modulation applied. If a control is already at the limit, but you want to go further, move the control the opposite direction, then back again.
Once your mappings are dialed-in, press map to exit.

After mapping is applied, affected parameters can still be manually manipulated. Manual changes alter the baseline from which your modulations are articulated.

To adjust the depth of an existing mapping, simply follow the same process above. Once you re-select the mapping source, you’ll see the current depths of modulation indicated with varying light intensity at each destination.

Clearing a Single Mapping

To clear just one mapping:

Select the source for mapping (as above).
Hold clear and interact with any mapped parameter to release only that parameter from the source’s control.

Clearing all Mappings of a Source

If you want to clear all mappings for a given source (eg: stop the lfo from dominating a patch):

Hold map and press clear (you can now release both keys).
Any source with active mappings will be lit.
Press the source’s key to release all of its mappings.
Press map to exit.

Muting

Sometimes, we may want to simply mute a modulator’s effect without clearing it:

Hold map and press mute (you can now release both keys).
The mute light will turn on. All sources will dimly light.
Press the source’s key to mute it. The source's light will become bright.
Press map to exit.

You'll see the mute light stay on, indicating that at least one mapping is muted.

Note how the process for clearing and muting are very similar. It's a good moment to commit the process to memory: Holding map then pressing a modifier (like clear or mute) will affect the source as a whole.

Polytimbrality

In Atrium, polyphony is not just about setting five different pitches and articulations, but also in the application of mappings. Many parameters are themselves capable of polyphony, leading to the "polytimbrality" demonym. All five of Atrium's sliders are a good case for this point. Take energy for example, which can be set uniquely for all five voices. With only a single slider though, access to this voice-wise control is found in the mapping system.

So now we must understand that some modulators are polyphonic, while others only monophonic. Atrium will always try to maximize polyphony when mapping, but if either source or destination are only monophonic it will fall back to unified control. This is described further below, but for now let's get into the sources.

Continuous Modulators

lfo

An internally-generated low-frequency oscillator (LFO). See lfo for much more detailed information!

speed adjusts the rate of oscillation, from around 10 seconds at its minimum into (low) audio rate at its highest intensity (around 100Hz).

phase staggers each of its five voices in time, revealing the polyphony of the LFO.

shape cycles through different waveforms to change the character of oscillation.

Atrium holds 11 default shapes! Learn how to access them in the sequences section.

notes

A signal that represents the frequencies selected by notes. This signal is polyphonic, just like the notes it represents.

The octave keys shift this modulation signal up and down.
glide is not factored into this modulation signal.

freqs

Captures the frequencies of spectre's three bands.

morph is factored into the expression of freqs modulation.

When mapped to a polyphonic destination, this modulation is polyphonic — the left channel is voice 1, centre is voice 3, and right is voice 5. Voices 2 & 4 take the midpoint of their nearest channel.

When spectre is at it's minimum and its effect is not heard, the frequency touchplate (and lens) become a great tool for directly manipulating polyphonic parameters in a manual fashion.

step

This signal turns the lens sequencer into a stepped, rising ramp. The range is dynamically controlled such that the first lens step provides no modulation and the last step provides maximum modulation.

contour

The envelopes created by contour are exposed for further note-event mapping.

Since contour is built upon the interactions between sustain, ramp, and length, there’s much to be explored here!
Try mapping contour to notes, and then stretch the contour for each pair. Now, sustain modulates notes polyphonically.

loudness

Captures the overall amplitude of the instrument.

Note that if your volume is low, you will not likely hear the effects of this mapping.

loudness is highly useful when coupled with spectre, allowing self-limiting delay feedback that can stop you flying off into saturated echoes.

Event Modulators

An event-type modulator is sort of like a square pulse with an extremely slim width. They’re basically the ‘onset’ of an event, rather than a continuous stream unfolding.

These modulators are useful for stepping through sequences or triggering contours, but they’re also useful for adding percussive movement to continuous parameters like spectre’s frequencies and the energy, tone, timbre trio.

change

Creates an event whenever a voice’s pitch changes.

Turn ramp all the way counter clockwise.
map change to sustain to trigger the contour only when that voice has a note change.
This is particularly fun when a chord is spread, as notes movement might not change all voices at once.

change is polyphonic, but when mapping to a monophonic destination only changes of the root note will trigger an event. This means that changing chord will not trigger events, but moving notes will.

When scale is disabled (unquantized mode), the change modulator is replaced with a set of differentiators. We use this big word to say: the more rapidly you move notes, the larger the modulation signal created.

clock

A steady pulse emitted according to tempo. Every clock pulse creates an event.

See the clock page for much more detailed information!

Limit Modulators

When any knob or slider reaches the extremes of its range (minimum or maximum), a modulation signal is generated. These limit-type modulators are binary in nature — simply on or off. Through most of the range the signal is zero, presenting nothing of import. When the control reaches the selected limit, a full-scale modulation is activated.

These sources are a powerful tool for extending the playability of Atrium. Canonically these signals are used for advancing sequencers, or automatically pressing keys. This doesn't stop them from mapping to continuous controls though, just be mindful of how deeply parameters can be affected by the full-scale signal!

To map a limit-modulator:

Hold map and move a slider or knob to its minimum or maximum value. The corresponding light will illuminate and the source is selected for mapping.
You may now release map.
Select any keys to 'press', and/or adjust destination controls.
Press map to exit.

Now, bring the newly mapped slider or knob to its extreme to articulate the new mapping.

Limit modulators unlock powerful compositional actions! For example, they can transform sustain slider flicks into a lens -stepping meta-gesture.

Both minimum and maximum limits are independent sources. They can be applied to orthogonal actions, but it's also useful to apply them in tandem. Try mapping energy's limits: 'up' to increase the octave, and 'down' to decrease. Now a single motion controls sonic timbre as well as harmonic range.

Monophonic vs. Polyphonic Parameters

Atrium has two parameter archetypes: monophonic and polyphonic. Monophonic parameters are single-focus, either unifying all voices under their purview or representing a singular function. Polyphonic parameters, on the other hand, hold a value for each voice.

To illustrate the difference: what should happen when we map contour to volume? While each of the five voices have their own contour which reflects their unique enveloped articulations, volume is a final-stage control, operating on a mixed-down stereo signal. As a result, volume can only meaningfully parse one channel of control, and is considered a monophonic destination.

When a polyphonic modulator is mapped to a monophonic destination, the value of the third voice becomes the single channel of control.

So what happens when volume receives a polyphonic signal from contour? Rather than merge all five envelopes into a gurgling mess, Atrium only sends the contour of the central, or third, voice.

Other examples of monophonic parameters:

tempo, which controls the rate of the clock
lens, which controls the spectral placement of spectre's filters
scale, which sets the field of possible note values for all voices

Alternatively, what happens when contour is mapped to a destination like notes? Since these are both polyphonic parameters, we'll hear (and see!) each voice selecting its own new note from the scale along its contour — try hand-playing from the strum touchplate to hear each voice individually arpeggiate as its envelope opens and closes.

Even though the energy meter in the timbral-control section only reflects the third voice, energy / timbre / tone are all polyphonic parameters. Polyphonic modulations to these destinations will be applied to each voice individually.

Pickup Behavior

Since you've been exploring mapping, you may have noticed that after moving knobs and sliders to set modulation depths, some lights have turned on around the interface after exiting mapping. These lights indicate that the physical position of the control has diverged from it's symbolic level.

If the difference between theory (parameter level) and practice (physical level) is small, these lights will be dim, and you can carry-on as normal. The difference between the two states will be reconciled as you next move the knob, and you probably won't notice.

If however this difference is large, you'll see these 'pickup' lights lit brightly. The control will no longer respond to your immediate touch, and you'll need to move the physical control toward the light until the link to the parameter is regained. Often a small nudge will be enough, but you may have to move up to halfway in the extreme case.

When the physical state is fully caught up, the lights will be extinguished.

Pickup behaviour is most notable when loading patches. You can simply ignore these indicators until you need to move that specific parameter.

External Modulation

External modulation is described in full in the On Connections sections for MIDI and Control Voltage.

For now we'll just mention that both control voltage and continuous MIDI sources are distributed through this same mapping system. Everything you've learned above will be equally useful in that extended context.