Make a sound compatible with itself
Tutorial | Jan 20, 2025
In this video, I explain how the order and rhythm of overtones are crucial in determining whether a sound is perceived as a single note or a chord. By using devices like the comb filter, we can manipulate and organize overtones to create harmonious sounds when playing chords. I demonstrate various techniques for improving sound quality and harmony, especially when using noise samples and synthesizers, and show how these approaches can lead to better-sounding pads and textures.
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Summary #
Maybe you don't watch the video, here are some important takeaways:
In this video, I discussed an interesting concept I encountered during sound design sessions: the significance of overtones in determining whether a sound is perceived as a single sound or multiple sounds when playing chords. I begin by describing a common problem in sound sampling. When a sound is played as a single note, it often sounds fine, but when multiple notes are played to form a chord, the sound becomes unpleasant or doesn't fit as expected. This phenomenon occurs because of the rhythm and order of the overtones.
The human brain is highly attuned to the harmonic series, where overtones are multiples of a fundamental frequency. This helps us differentiate between a single sound and a chord. When the overtones align perfectly in multiples of the fundamental, it is perceived as a single sound. However, if the rhythm of these overtones is disturbed or the overtones are out of tune, it can make a sound feel like a dissonant chord.
To illustrate, I explored techniques such as voice stacking and using a stack spread, which involve playing multiple notes. By manipulating these elements, I demonstrated how changes in overtone alignment could turn a single sound into a cacophonic one and vice versa.
One method I explained involves using a sampler loaded with a noise sample, paired with a bandpass filter and key tracking. By enhancing the resonance and using techniques like exponential FM, we can bring certain frequencies into focus and suppress others, transforming noise into playable lead sounds. The goal here is to manipulate the fundamental frequency and align the overtones correctly.
A crucial tool I introduced is the comb filter, which is particularly adept at ordering overtones. Unlike a simple bandpass filter, a comb filter can amplify a series of harmonics evenly based on the fundamental frequency, producing natural-sounding results, akin to string instruments like guitars. This feature makes the comb filter very effective for creating sounds that resonate well together and for playing chords that do not clash harmonically.
I highlighted practical applications by setting up a sound design environment where sine oscillators modulate each other, with the final sound processed through a comb filter. This setup showcased how adjusting certain settings alters the amplification of specific overtones, proving the importance of hitting the right frequency alignments.
To emphasize the point, I compared sounds processed with and without a comb filter. Without one, sounds were scattered and messy, whereas with the comb filter, they were significantly more cohesive and harmonious. This demonstrates how comb filters organize frequencies in a chromatic fashion, allowing for musical and structured sound production.
I concluded by creating pad sounds with rich overtones, modulating them with random or LFO-based pitch changes. With the comb filter in place, these sounds are coherent and pleasing; without it, they revert to a chaotic state.
I also provided a practical example using a sampler with a noise sample, demonstrating how turning off key tracking and applying a comb filter in the FX grid can dramatically improve the sound quality when playing multiple notes together.
In essence, my video aimed to show how understanding and manipulating overtones with tools like comb filters can transform the quality and perception of sounds, enabling more creative possibilities in sound design.
Transcription #
This is what im talking about in this video. The text is transcribed by AI, 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.
[00:00:00] Hey, folks, today I want to talk about something you probably already found out for yourself in a way.
[00:00:05] So let's imagine you sample a sound or you created a sound in a sound design session and you put it into the sampler and then you discover that it sounds okay or exactly the same.
[00:00:17] But then you play multiple notes, you want to play a chord and then it sounds horrible. It doesn't fit. It doesn't work anymore. Right.
[00:00:27] So the reason for this is the overtones, the rhythm of the overtones. They are pretty important to a sound. So we can have this one sign partial
[00:00:37] and your brain says clearly this is one sound playing a melody. Okay. And then we have something like this.
[00:00:50] And your brain says, Oh, this is actually three sounds playing. This is a chord. This is not just one sound. Your brain could say
[00:00:57] this is one sound. So all these harmonics belong together. Right. But that's not what your brain says. It says it's clearly three sounds. And the reason for this is that it's because of the order of these overtones.
[00:01:12] So let's imagine we have this sound now.
[00:01:17] We have multiple overtones here and your brain says, Oh, this is one sound.
[00:01:21] Clearly, this is one sound playing a melody.
[00:01:27] Oh, sounds like a chord. So this is actually three sounds playing together.
[00:01:39] And the brain does this because of the overtones. So we have here one fundamental. This is the note actually I'm playing. Then we have all these overtones and the overtones are in a clear orderly rhythm. So this is here two times the frequency of this. This is three times the frequency of this. This is four times the frequency of this.
[00:02:01] So all these overtones are just a multiple of this fundamental frequency. This is how the brain knows when you play one sound or multiple sounds. It's so tuned to this order to this rhythm that it can clearly distinguish between multiple sounds or, you know, just one sound playing.
[00:02:22] So if you bring this order out of rhythm in a big way, then this doesn't work anymore. So let's say instead of using your one sound. I'm using voice stacking.
[00:02:36] I'm using a stack spread and then I increase here. This by one. So now I'm playing one sound. You get this kind of song.
[00:02:51] Something we had just before. So maybe you're like this. So again, your brain says, oh, this is one sound because the structure is here in a perfect rhythm. It's just a multiple of the fundamental frequency, which works. But then we can bring this order out of tune.
[00:03:16] So now it doesn't sound like one sound anymore to your brain. It could be a very weird chord.
[00:03:43] So the rhythm is kind of out of tune. I mean, you can still hear it's one sound in a way, but it doesn't sound that pleasing anymore. If you play also your multiple notes.
[00:03:53] All the overtones move basically with the fundamental in the same, yeah, in the same space on the same frequency space. So when you play a melody, it sounds for your brain still like one sound.
[00:04:11] But if you just hear one sound, it could be a chord. Yeah, and this is because of the rhythm of the overtones. So if you have like a noise sample, and you want to bring in some or you want to use it as a lead sound, I made a video about this here with the sampler.
[00:04:31] So you use a sampler, put a noise sample in there, use then here bandpass filter or sleep bandpass filter, use key tracking, crank up here the resonance, right, put this to C3, and then it brings in a fundamental frequency and you play like a sign partial below the noise, and the noise is kind of damped down or goes through the filter here and excites the filter in different ways.
[00:04:57] So this is one way of making like a noise sound to a lead sound or a sound that you can play. But here we just focus on one on the fundamental. It's the most important. It's the fundamental frequency, of course, but there are other ways. So let's say we have here.
[00:05:18] Let's put this back. No voice stacking. We don't need it anymore. And then we use maybe a second sign. So let's say we use exponential FM, something like this.
[00:05:39] You get very wacky overtones.
[00:05:50] Let's say you want to make this something you can play as a chord if you play your multiple notes.
[00:05:58] This is a major chord. It sounds very horrible. Sounds horrible. You could try and use a bandpass filter.
[00:06:13] You put this here, C3, key tracking is on, bandpass 4, and then we can crank up here the resonance, right? So you can hear all the overtones are quieter, and we only focus here on the fundamental frequency.
[00:06:36] Then you can kind of play it with multiple notes.
[00:06:45] So yeah, this is kind of one way of doing it. But if you have some of the partials here, actually not being at the center frequency of this bandpass filter, you can see they are just muted or pulled down in volume.
[00:06:59] But some of these frequencies here exactly this frequency to make it sound a bit louder. But you get the idea. We have just one bandpass, and this bandpass is at the center frequency here, and it tries to amplify this and pulls down all the other frequencies in volume a bit more.
[00:07:18] So it would be nice to have multiple of these bandpass filters stacking on top of each other and then amplifying all the harmonic series. So the multiple of the root frequency here. So two times, three times the frequency and so on.
[00:07:39] So we can do this. But turns out we have actually here the comforter for this. The comforter does exactly this. It's evenly spaced. You have the center frequency here, and then all the overtones of the comforter are actually exactly in this harmonic series rhythm.
[00:08:00] I can show you this here, maybe with the noise thing, because every time I show the comforter, it's probably because of the physical modeling, right? We have a very short noise burst going into the comforter here with a lot of feedback.
[00:08:21] So maybe we need an AD at the end.
[00:08:48] And it sounds so nice because you can see this here. This is the fundamental frequency. All the overtones are perfectly in rhythm of the harmonic series. And it sounds like a guitar.
[00:09:02] So this is how I showed usually the comforter for physical modeling, but you can also use it more in a tamed way. You don't need to crank up here the resonance all the way. You don't need the filter here for a moment.
[00:09:15] So we can use this to filter out certain frequencies we don't want and amplify certain frequencies we do want in the sound.
[00:09:24] So here's kind of some similar setup. We have multiple sine oscillators here feeding audio into the pitch input of the other. And this one, the last sine oscillator here is actually producing the sound.
[00:09:38] And then we go into an envelope and then I go here into two Comb Filters having the same frequencies here just to amplify the right harmonics.
[00:09:50] And I also have here a dry path so you can switch between the original sound and what comes out of the Comb Filter so you can see the difference. So this is how it sounds here with the Comb Filter.
[00:10:01] (guitar playing)
[00:10:15] And this is without.
[00:10:17] (guitar playing)
[00:10:26] So you can bring order to the overtones with these kind of devices in a more like more amplified way or subtle way. So it depends on you how much you want to influence the sound actually.
[00:10:38] But we can also hear when I change some of the settings here in front that we amplify certain partials in here so they come up in volume and certain partials go down in volume.
[00:10:50] And this is because we don't always hit with the sound processing or the sound generation here. Always the right overtones that align with the Comb Filters.
[00:11:02] So we sometimes hit exactly the right frequencies and sometimes not. So it sounds like this. Just one sound here.
[00:11:10] (guitar playing)
[00:11:11] Then we change something here.
[00:11:13] (guitar playing)
[00:11:19] As you can see now we don't hit any overtones or any specific frequencies of the Comb Filter so everything is down in volume.
[00:11:30] (guitar playing)
[00:11:36] Now we hit exactly the right frequencies.
[00:11:39] (guitar playing)
[00:11:56] And here I wanted to amplify the effect a bit with using two Comb Filters but you can also try to invert the signal, phase invert the signal and then combine it here with the Comb Filter to actually get rid of some of the frequencies in between.
[00:12:11] This is also possible. But in my opinion here this is kind of a nice setup or the Comb Filter is a nice device or module. There's also here device.
[00:12:22] But this one has no key tracking here. But negative also negative feedback. And I think this is here is oversampled. It sounds a bit better than this one here.
[00:12:32] So the Comb Filter device or module is actually a nice way of ordering the overtones to make the sound compatible with each other so you can play multiple notes.
[00:12:47] You have the right overtones, the right order, the right rhythm and it sounds more like a single sound instead of a chord and you can combine then these sounds with multiple notes and play actually chords or chord progressions and it sounds nice.
[00:13:02] (guitar playing)
[00:13:07] And I was discovering this here. That's actually a nice setup here to create pad sounds with different overtones. So I use here Valhalla, right, drown everything into reverb.
[00:13:21] (guitar playing)
[00:13:38] And then use an LFO or maybe a random mod and then slowly modulate here the pitch modulation.
[00:13:52] (guitar playing)
[00:14:09] Maybe a bit too fast. That's the second one.
[00:14:19] (guitar playing)
[00:14:48] And it sounds kind of okay and nice because we ordered the overtones if I disable this here. It sounds like a complete mess.
[00:14:58] (guitar playing)
[00:15:05] And because of the comfort you can do whatever you want in front here, right. It's kind of ordered like a pitch, like a chroma, but not for keys. It's more for frequencies for what are harmonic series.
[00:15:21] (guitar playing)
[00:15:42] (guitar playing)
[00:15:59] (guitar playing)
[00:16:16] So kind of a cool way of creating interesting sounds just with the setup here.
[00:16:23] So this is more like a practical example here. We have a sampler and I just recorded here a bit of noise crackle into the sampler.
[00:16:32] And I probably want to switch off here the key tracking so every note plays the same original pitch.
[00:16:41] So we could take here the bandpass filter. Key tracking is 100%. This is C3 and then we crank up here the resonance.
[00:16:51] (guitar playing)
[00:17:00] And then we excite more or less here the fundamental frequency. But you can also switch this off and go into the FX box here and use an FX grid.
[00:17:10] In here we use a comp filter. There is a comp filter device, but it's not key tracked. So I always use this one here.
[00:17:20] In my opinion this also sounds much better. The key tracking is on. The device, the FX grid here goes to polyphonic voices, maybe 12, I don't know.
[00:17:30] And then we can play now multiple notes and crank up here the resonance.
[00:17:36] (guitar playing)
[00:17:42] Maybe use your auto gate. A bit longer, 2 seconds.
[00:17:47] (guitar playing)
[00:17:50] We have more like a fade out. The voices are staying alive until this auto gate here takes off the voice.
[00:18:00] (guitar playing)
[00:18:25] Maybe texturize and pull down here the speed.
[00:18:29] (guitar playing)
[00:18:40] You can see it sounds much, much better because you also take all the overtones into account instead of just the fundamental with the bandpass.
[00:18:49] So that's it. Reboot, yeah.
[00:18:54] (guitar playing)
[00:19:18] And if you play just one sound here, maybe C.
[00:19:23] (guitar playing)
[00:19:26] Let's go knock the fryer here.
[00:19:29] (guitar playing)
[00:19:32] Or something like this. And then you record it here.
[00:19:36] (guitar playing)
[00:19:54] And then take this here, master recording, put it into the sampler, then you can use pitch tracking.
[00:20:04] It's probably C3.
[00:20:07] (guitar playing)
[00:20:22] And then you can play chords with this and it sounds much, much better than having just the bandpass filter.
[00:20:29] That's it for this video. Thanks for watching, leave a like, leave a subscription and have fun with the combo filter of course. See you next time.
[00:20:37] (guitar playing)
[00:21:06] (guitar playing)