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Bitwig Keytrack Plus Modulator - Modulation based on Pitch and Notes

Bitwig Guide | Apr 14, 2023

KeyTrack Plus allows you to create custom modulation curves by mapping keyboard notes to modulation values using a simple graph interface, where each key's position is visually represented. You can easily adjust the modulation amount globally and draw unique curves to control how parameters like cutoff respond to different keys, enabling highly expressive modulation. This flexible system lets you apply nuanced or unconventional modulation to any input, making creative sound shaping straightforward and intuitive.

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Short Overview

With KeyTrack Plus, I can easily map keyboard notes to any modulation target using a customizable curve. By drawing directly on the graph, I decide how each key position influences modulation, whether it's opening up a filter as I play higher notes or creating more complex patterns. The central C3 key acts as my reference point, and adjusting the curve is as simple as sketching with a pencil tool. This gives me flexible, intuitive control over how my keyboard playing shapes the sound.

Introduction to KeyTrack Plus

In this video, I demonstrate and explain the functionality of KeyTrack Plus, a modulation device that essentially acts as a transfer curve for node (note) inputs. The main feature is a customizable graph interface that allows me to map keyboard notes to modulation values, providing highly detailed and creative modulation control over synthesizer parameters.

The User Interface

The Graph Editor

At the heart of KeyTrack Plus is the graph editor. This editor visualizes note input as a horizontal range, with a white dot representing the key currently being pressed. For example, C3 appears in the middle of the graph, higher notes (such as C4) appear to the right, and lower notes (like C2) appear to the left. This layout lets me see exactly which part of the curve will be affecting my sound depending on which note I play.

Modulator Output

The device includes a modulator output that sends the resulting modulation value to whatever parameter it is assigned to. In the inspector panel, there's also a global output amount control, allowing quick adjustment of the modulation strength for the entire modulator, making it easy to scale the effect up or down.

Applying KeyTrack Plus to Parameters

Customizing Modulation Amounts by Note

In practice, I use this module by mapping it to parameters such as a filter cutoff. The modulation value for each key is determined by the curve I draw in the graph editor. For instance, if I create a curve that rises as you move right, higher notes will open the filter cutoff more as I ascend the keyboard. C3 (the midpoint) will have no effect when the value is zero, while notes above C3 increase the modulation value, and those below can do the opposite, depending on how I draw the curve.

Flexible and Creative Sound Shaping

I can freely redraw the curve using the pencil tool or other drawing tools. If I reverse the curve, higher notes will decrease parameters like the filter cutoff instead of increasing them. I can also clear the grid and create step patterns or irregular shapes, so every key can have its own unique modulation value, lending itself to complex and evolving effects.

The Concept of a Transfer Curve

A transfer curve, in this context, is a mathematical mapping from input values (here, MIDI note numbers) to output values (modulation amounts). By shaping this curve, I decide precisely how different notes influence whatever sound parameter I am modulating. Unlike standard keyboard tracking, which is a linear mapping, this lets me define non-linear, stepped, or even random-like behaviors.

Practical Applications

Sound Design Versatility

By having direct control over which key sends which modulation value, I can push the creative boundaries in sound design. For example, I can make only certain keys trigger special effects, or set ranges where nothing happens and others where the parameter jumps or morphs dramatically. This workflow is far more detailed and flexible than traditional key tracking, making it ideal for atmospheric patches, experimental tones, or simply for more nuanced, expressive playing.

Conclusion

KeyTrack Plus turns the keyboard into a customizable modulation source. By allowing me to paint precise relationships between played notes and modulation targets, I can easily shape expressive sound responses or invent new playing articulations. This approach leverages a simple visual interface for detailed and limitless sound design possibilities, making it an easy yet powerful tool for musicians and producers seeking more interactive control over their instruments.

Full Video Transcription

This is what im talking about in this video. The text is transcribed by Whisper, so it might not be perfect. If you find any mistakes, please let me know.
You can also click on the timestamps to jump to the right part of the video, which should be helpful.

Click to expand Transcription

[00:00:00] KeyTrack Plus is basically a transfer curve for node inputs.
[00:00:05] We have a graph, we can change or customize here, and we have a modulator output.
[00:00:11] And we have in the inspector here an output amount where we can change the modulation
[00:00:15] amount globally for this modulator.
[00:00:19] So when we apply this here to Polysyn, you can see we have already graphed in here.
[00:00:24] And we can open up the editor by just clicking on the space.
[00:00:29] And you can draw in anything you want.
[00:00:32] And the input key or the key on your keyboard is basically represented here by a white dot.
[00:00:38] So when I press C3, it's right in the middle.
[00:00:43] C4, one octa fire, it's here.
[00:00:47] C3 or C2 is one octa floor, it's here.
[00:00:51] Right, you can see here C3 is in the middle.
[00:00:55] Every key that you're pressing this higher goes to the right side and everything that's
[00:00:58] lower goes to the left side.
[00:01:01] And then with this curve, you can draw in how much modulation you want to apply.
[00:01:06] So when we use this here on the cutoff, right, we modulate the cutoff with this, the higher
[00:01:11] we go on the keyboard with the keys, the more we open up here the frequency.
[00:01:16] So C3 does nothing because we're staying here at zero.
[00:01:24] But the more we go up, the more modulation value we apply because of this curve.
[00:01:28] You can also draw this completely in the opposite direction here by using a pencil, maybe doing
[00:01:34] something like this.
[00:01:36] And now C3, or let's actually do this here better, let's remove all the keys.
[00:01:51] So now C3 is in the middle, does nothing, but when we go up, the cutoff actually closes.
[00:02:00] Right.
[00:02:01] And then we go down, we open up.
[00:02:06] So we can paint in here how much modulation you want to apply on each key you are pressing.
[00:02:12] So we can also do certain things, something like this here, or maybe change the grid editor
[00:02:20] here or the grids and then paint in very weird things.
[00:02:28] And each key then gets a different, different modulation value.
[00:02:40] Okay.
[00:02:41] So it's a transfer curve and you can map input notes to modulation value and then modulate
[00:02:47] something, easy peasy.
[00:02:49] [BLANK_AUDIO]