Bitwig Melodic Filters - Scale based Filtering with Modulations
Tutorial | Oct 15, 2025
This video demonstrates how to modulate filter frequencies in Bitwig (or any modular DAW) so modulation lands on musical notes within a chosen scale, not just random frequencies, by using harmony theory and quantizers. The key insight is that most Western scales are constructed by stacking perfect fifths (seven semitones apart), so you can use a quantizer set to six steps and a modulation range of 42 semitones to achieve accurate, in-scale modulation, with an initial frequency offset depending on your root note. This method provides a musically meaningful way to randomize your sound design while always staying within your chosen key, and is applicable to any environment that allows semitone-based modulation.
You can watch the Video on Youtube
- support me on Patreon
Short Overview #
Today I explored how to keep filter modulations musically in scale, blending harmony theory with sound design. By understanding that most scales are built from stacking fifths, I showed how to use quantizers in the modulation system to ensure we only hit notes within a chosen scale. This approach allows for musical results even when using random modulation, and it's not limited to Bitwig Studio but can be applied in any DAW or modular setup. It’s a great technique for creating harmonically aware sound design and adding a musical touch to filter movements.
- Demonstrates how to modulate a filter to only allow frequencies in a chosen musical scale, using Bitwig Studio as an example.
- Explains the concept is applicable to any DAW or modular system, not just Bitwig.
- Shows how random modulation of filter frequency is usually out of scale, resulting in non-harmonic sounds.
- Describes how musical scales can be constructed by stacking fifths (7 semitones apart), relating to the circle of fifths.
- Illustrates that C major and A minor use the same notes, only differing by starting point.
- Provides a method to ensure modulation stays within a scale using quantizers:
- Choose the root note for the scale.
- Set quantizer resolution to 6 and modulation range to 42 semitones (six 7-semitone intervals).
- Adjust the center frequency to match the related note of your chosen scale.
- Emphasizes you can apply this logic to easily hit in-scale notes using modulators or quantizers in synths and effects.
- Suggests alternative method using Bitwig's voice stacking and modulation with value mapping, spacing voices by 7 semitones for harmonic results.
- Notes this approach is useful sound design knowledge blending harmony theory and technical modulation.
- Mentions presets will be available for Bitwig, making in-scale modulation easier for complex filter responses.
- Highlights the broader relevance to any environment where modulation can be set in semitone steps.
Introduction: Bridging Sound Design and Harmony Theory #
Today I want to share an interesting technique that integrates sound design with harmony theory. Although I am demonstrating this in Bitwig Studio, the knowledge and methods here are broadly applicable to any DAW or modular system that allows modulation and quantization. The goal is to make filter modulation musically relevant and tied to a chosen scale, so the filter only sweeps through frequencies that correspond to the notes of that scale.
Playing Within a Scale #
I start by playing some music within a specific scale using a piano instrument, making sure everything fits harmonically. Next, I add a filter, specifically a Band Pass Filter, and apply random modulation to the filter’s frequency using a random modulator synced to the eighth note.
Problem: Random Modulation is Not Musical by Default #
When you use a random modulator to change the filter frequency, the modulation jumps to arbitrary frequencies. These points rarely match up with the notes in the scale you are playing, so it can sound musically disconnected or even dissonant.
The Challenge: Scale-Constrained Modulation #
Naturally, you would want the modulation to align with musically meaningful frequencies , in other words, the notes of your current scale. Bitwig Studio’s modulation system does not have a built-in scale quantizer or a “diatonic transposer” for modulation signals. This presents a unique problem: How do you ensure the filter frequency is only modulated to pitches within your chosen scale?
Visualizing Notes and Scales #
To clarify this, I refer to the piano roll to visually show what I am trying to achieve with modulation. In scales like C major or A minor, all the white keys are included but different starting points create different interval structures. All minor scales and major scales are constructed from the same set of intervals, just offset, which is why C major and A minor use the same notes but start at different points.
Understanding Fifths and Construction of Scales #
Every major or minor scale is constructed by stacking perfect fifths, an interval of seven semitones. This is the foundation of the "circle of fifths." Starting at any root note and stacking fifths will generate the notes of a given scale.
- For example, beginning at C and moving up by seven semitones repeatedly will hit all the notes in C major, though sometimes those notes must be transposed down an octave to fit within a single octave range.
- This process works for every diatonic scale.
Understanding this allows for a systematic way to select scale degrees for modulation , you don’t have to randomly guess which frequencies will fit.
Practical Solution: Quantizing the Modulation Signal #
Using a Quantizer #
To force the random modulation to “land” on frequencies corresponding to notes in the scale, I use a quantizer device. Here's the logic:
- Calculate how many unique notes you want to hit (usually six, because you already have one root note).
- Each step should span a fifth, or seven semitones. Multiply seven by the number of notes (six), resulting in 42 semitones.
- Apply modulation quantized to steps that correspond to these intervals.
- Adjust the starting offset frequency to shift the pattern to your scale’s root note. For C major or A minor, start at F; for D sharp minor, work out the correct offset accordingly.
Step-by-Step Modulation Setup #
- Set the quantizer’s resolution to six steps.
- Set the modulation range to 42 semitones.
- Adjust the oscillator or filter’s base frequency to the required starting note (e.g., B for D sharp minor).
- Modulate through the quantizer so only frequencies related to scale notes are chosen.
With this setup, even a random or generic modulation will only hit musically relevant filter frequencies.
Alternative Method: Using Voice Stacking #
Bitwig offers another powerful approach using voice stacking with unison or polyphony:
- Stack multiple voices and use voice spread or value spread to increment frequencies by seven semitones per voice.
- This creates a layered sound where each layer fits within the chosen scale, creating interesting harmonic effects.
Raising the number of voices increases the density of harmonically related frequencies , for example, giving you all the notes of a minor or major scale at once.
Applying the Concept in Other Systems #
Though I demonstrate this in Bitwig, this concept works anywhere you can modulate in semitone steps and use quantization (for example in soft synths like Vital or Serum, or even hardware systems). If your system doesn’t support direct scale quantization, you can reconstruct the scale logic using fifth intervals and appropriate quantization.
Conclusion: A Blend of Theory and Practical Sound Design #
Understanding how scales are constructed from intervals of fifths allows you to design modulation schemes that always remain in key, making your sound design feel harmonically intentional. With tools like quantizers, voice stacking, and knowledge of scale construction, you can create presets and modulations that are musically coherent across instruments and DAWs.
This technique is not only useful for filter modulation but for any scenario where you want randomness or modulation sources to stay inside a musical scale, adding depth and musicality to your sound design workflow.
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] Hey folks, welcome back. I want to show you something today. That's not only interesting for Bitwig studio users
[00:00:06] Of course, I show it how it works in Bitwig
[00:00:09] But you can use it in every door in every modular system and it's also nice knowledge to have because it blends between sound design and
[00:00:16] Harmony theory. So let's say we play here in a certain scale some kind of music and I'm using a piano take nine, which just released today
[00:00:25] So we play in a certain scale
[00:00:28] [Music]
[00:00:37] Okay, so in scale and then you say, okay, let's put some kind of filter on that
[00:00:43] So we do this we use a filter plus here
[00:00:47] Low pass filter and we switch this to band pass filter and then we say we want to randomly modulate this
[00:00:54] We use a random modulator here eight note
[00:00:58] And then we modulate you the frequency knob of the filter. So let's say here by I don't know 50
[00:01:05] 50 semi-semitones, right and to show you where we end up on the frequency spectrum here increase the resonance
[00:01:13] And of course, this is random this is not in the scale that we just played so we're just T sharp minor
[00:01:26] [Music]
[00:01:33] Okay, so it's not in the scale we end up on the random positions in the frequency spectrum
[00:01:38] So what we want to do is of course, we want to just highlight or we want to end up on
[00:01:44] Frequencies that are in the scale of the scale. We are currently playing which is T sharp minor and this is not very easy here with the
[00:01:53] Modulation system in bitwig because we don't have no scale modulator or
[00:01:58] diatonic transposer for the modulation signal
[00:02:02] so we have to
[00:02:04] do something different, okay, and I show you first how it looks like at the piano role
[00:02:10] So we have an idea what I'm actually doing what I'm modulating, right? And this is what I mean by
[00:02:16] It plans between harmony theory and sound design because we modulate here to certain degrees and
[00:02:23] We end up on a scale because of harmony theory, okay
[00:02:27] So let's say we want to play in the scale of C major and we all know C major is very easy
[00:02:33] It's just all of the white keys, right?
[00:02:40] So C to C all of the white keys is C major very easy
[00:02:45] Also a minor turns out uses the same notes
[00:02:50] We just start on a different note
[00:02:53] So we start on a all of the white notes
[00:02:59] Up until a and you can see it uses basically all of the same notes just here is
[00:03:06] That's actually B is also here and then C is also here
[00:03:11] So all of the white notes just on a diff we start on a different point
[00:03:15] Which gives us different intervals, right for the first quartier. We have different intervals than for this first quartier
[00:03:21] So same notes very easy
[00:03:25] But the thing is all of these scales so C minor D minor E minor a major
[00:03:34] Whatever scale you can think of is actually constructed by just stacking fifths on top of each other
[00:03:41] That's why we also have the circle of fifth, right?
[00:03:43] So all of these scales are constructed out of just stacking fifths and fifths are
[00:03:49] Just seven seven semitones apart seven notes seven semitones apart
[00:03:56] very easy to remember and
[00:03:59] You probably say wait for that really actually here you can see that's clearly not seven semitones here
[00:04:04] We have two semitones here. We have two semitones here. It's just one semitone. Yeah, but that's just a compressed form of the scale
[00:04:11] So you can say let's start on C
[00:04:14] And then we use the first interval which is a fifth so we go up seven semitones
[00:04:20] One two three four five six seven right we end on G look it's in the scale
[00:04:27] One two three four five six seven look it's in the scale. It's D, right?
[00:04:32] One two three four five six seven. It's in the scale
[00:04:37] One two three four five six seven. It's in the scale
[00:04:41] One two three four five six seven. It's in the scale
[00:04:46] One two three four five six seven. It's not in the scale. So this one is not in there. It turns out
[00:04:54] Next note is actually seven semitones lower. So one two three four five six seven. It's F
[00:05:00] So with this we have to extend it or the real scale
[00:05:04] How the real scale looks like what you can see here is the compressed form
[00:05:09] It's basically just using all of these nodes and pulling down one octave one two three
[00:05:15] this one
[00:05:17] This one goes down right this one goes up
[00:05:20] So it's just skipping around an octave. So it's the compressed form
[00:05:24] So all of these nodes are within one octave. That's the idea behind it. So let's let's go back here
[00:05:31] Okay, so we know for C major
[00:05:36] We have to actually go down
[00:05:39] to F which is four semitones lower
[00:05:42] from C is it is it actually
[00:05:46] Yeah, we have to go down. I think
[00:05:50] One two three four five six and you have to go down seven, of course. Yeah makes sense
[00:05:56] So yeah, anyway
[00:05:59] So we have to start on F and then we can say seven semitones seven seven seven okay six until we have six nodes
[00:06:06] And then we end up basically on the scale of C major
[00:06:10] So it's very easy because we can just use a quantizer for that and say just
[00:06:17] Put a give us seven semitones each time and we are good, right?
[00:06:21] So we can do this here with the modulation system in different ways
[00:06:26] Maybe I yeah, I just leave this opening. So you can see it
[00:06:31] So what we can do now here is we can use a quantizer
[00:06:36] Quantizer and to use a calculator for now so you can see what I'm calculating
[00:06:43] This one
[00:06:45] Okay, so we have seven semitones and we need six nodes of why we have
[00:06:54] Of course, we have the first note here, which is F and then we have one two three
[00:07:00] Four five six nodes we need, right?
[00:07:04] So we have seven semitones times six ends up on 42, which is the maximum
[00:07:12] Value we want to modulate okay
[00:07:16] So we take here the sample and hold or the quantizer not the sample or the quantizer here and modulate this by
[00:07:24] exactly
[00:07:25] 42
[00:07:27] Semi tones 42 is actually 42. Yeah, it's 42
[00:07:33] 42 semitones and you want to
[00:07:37] Change the resolution to six because we have six nodes and then instead of using here the
[00:07:42] Random modulator modulated the frequency directly we modulate here actually the quantizer by exactly one and
[00:07:49] now
[00:07:51] We have here the root frequency which is C
[00:07:54] Which is not what we want. We just want to start on F
[00:07:58] Okay, so we go to F here F1 for instance and then we modulate this here by 42
[00:08:04] Which we have and then we should end up
[00:08:07] on
[00:08:09] Yeah C major maybe
[00:08:14] So this is how you do this actually it's not
[00:08:21] Easy maybe to get what I did here
[00:08:25] But you can see all of the scales are just stacked fifth or stacked seventh
[00:08:30] stacked fifth and sorry and
[00:08:33] We can do this easily with the quantizer here or maybe with some other tools
[00:08:39] So all I have to remember is basically that I have to use a quantizer with the resolution of six and I modulate this frequency knob by
[00:08:50] 42 semitones and it's true for every scale
[00:08:55] The only thing that changes now is basically the initial center frequency. I'm using F here
[00:09:03] so
[00:09:04] I'm basically
[00:09:06] Creating with this the nodes of a minor and C major
[00:09:11] There's no difference. We just random modulators and we end up on the same notes because
[00:09:18] a minor or C major and a minor just shares the same notes
[00:09:23] There is no difference there
[00:09:25] It's just important for melodies basically where you start and where you end to actually create a sense of having a minor or C
[00:09:32] Major, but you use basically the same frequencies. It's the same notes. It's the same frequencies all the same
[00:09:38] So when I want to change this for a different
[00:09:42] let's say scale and I use of course all the time
[00:09:47] D sharp minor we can see a minor is here and from a minor to F
[00:09:53] It's actually four semitones one two three four
[00:09:57] Which means when I want to play in a
[00:10:01] D sharp minor, right? I have to go down
[00:10:03] Four semitones, which is one two three four, which is B one, okay?
[00:10:11] So if I want to use B D sharp minor or F
[00:10:15] Sharp major, which is the same notes. I use I need to go down to B one
[00:10:22] Or B two whatever it needs to be a B note and then I end up basically in the scale of D sharp minor
[00:10:30] okay
[00:10:32] Okay, so it's perfectly in scale
[00:10:53] It's very easy
[00:10:55] All you need to remember is basically other quantizer setting that you have six here and that you modulate this by
[00:11:01] 42 and then you need to remember basically the offset frequency which is B for D sharp
[00:11:07] But you can also just save this as a preset and call it today, right?
[00:11:11] And then you modify it for different scales and you have it ready to go
[00:11:15] another way of doing this is
[00:11:19] When you use for instance here the voice stacking, right? We can use fit or plus here with voice takings
[00:11:25] We have this multiplied and we use your stack
[00:11:29] stack spread and
[00:11:32] We can switch this to value
[00:11:34] So value is interesting because it not only modulates between zero and plus one it modulates actually in
[00:11:41] Decimals, so we have one two three four five and so on so what we can do with this is
[00:11:48] So let's say we have your voice taking on three three voice decks and you modulate this here by exactly seven semitones
[00:11:56] So that's a bit easier
[00:11:59] Right so the first
[00:12:02] The first voice is actually on C here and the next voice is seven seven tones higher and
[00:12:08] Second voice is again seven seven tones higher and so on so we have here a stack of
[00:12:16] Seven fifths and seven semitones a part of each of these frequencies, which is also nice to have
[00:12:23] So we go down here again to be one maybe
[00:12:26] And we increase here the voice decks to eight so we have eight different frequencies. We have basically a nice harmonic
[00:12:34] modal
[00:12:37] You
[00:12:39] Maybe use a test tone here test tone
[00:12:57] EQ plus
[00:13:07] Right all the notes here of the sharp minor maybe more voice decks
[00:13:15] So as you can see if you know what's going on
[00:13:35] then
[00:13:37] Then yeah, you can play around with this so you need to know
[00:14:01] How these scales are constructed and you can create modulation signals that are easily in the scale
[00:14:06] So this is how I do it and I want to show you this because I just create some presets
[00:14:11] Coming to bitwig. I don't know when it's coming
[00:14:16] but I'm creating some presets here for the filter plus and for some of the filters and
[00:14:21] Sometimes you need to end up on a scale
[00:14:24] It you just want to have a nice harmonic response from the filter and you can do it in this kind of way
[00:14:31] So I want to show you this and like I said, it's not only interesting for bitwig
[00:14:35] You can use this anywhere where you can modulate in
[00:14:39] Semi-tone steps and you have a modulation system maybe in vital maybe in serum or whatever
[00:14:44] some of these
[00:14:46] Systems or synthesizer actually use scales for the modulation system or for the modulation
[00:14:52] Signals in bitwig. We don't have it, but sometimes it's nice to know how everything comes together
[00:14:58] how everything works together and
[00:15:01] Yeah, that's it basically. Thanks for watching. See you next video leave a like leave a subscription
[00:15:06] See you then bye