Building a comb filter in Pure Data Vanilla from scratch.
A comb filter is a filter created by adding a delayed signal to itself, creating constructive and destructive interference of frequencies based on the length of the delay. All we have to do is delay the signal a little bit, feed it back into itself (pre-delay), and we get that pleasing, high-tech robotic resonance effect.
There’s no talking on this one, just building the patch, and listening to it go.
0:00 Playing back a recorded file 0:35 Looping the file 1:00 Setting up the delay 2:08 Frequency controls for the filter 2:52 Setting the range 3:48 Automatic random frequency 4:25 Commenting the code 5:39 Playing with settings
Talking through the concept of an artificial neuron, the fundamental component of artificial intelligence and machine learning, from an audio perspective.
I’ve made a few videos recently with “artificial neurons” including in Pure Data and in Eurorack, and, in this video, I discuss the ideas here in more detail, specifically how an artificial neuron is just a nonlinear mixer.
An artificial neuron takes in multiple inputs, weights them, and then transforms the sum of them using an “activation function”, which is just a nonlinear transformation (of some variety).
Of course just making a single neuron does not mean you’ve made an artificial intelligence or a program capable of “deep learning”, but understanding these fundamental building blocks can be a great first step in demystifying the growing number of machine learning programs in the 21st Century.
More music and sound design with artificial neurons:
I set out to make a tutorial about making a simple sequencer in Reaktor 6 Primary, and got way too long-winded, so this first part is just about making a low-pass gate (LPG).
A low-pass gate is a low-pass filter that is functioning as a VCA. When it isn’t triggered, the filter’s cutoff frequency is subaudio, not letting any audio pass. When triggered, though, the cutoff frequency goes up, letting all frequencies through. In analog, too, this motion of the cutoff frequency is performed by vactrols, adding a quick attack and release that some compare to the sound of bongo.
In this video, I make a digital LPG, talking through the best numbers for an effective result.
0:00 Let’s make a sequencer! 0:54 Making our usual sawtooth synth 1:24 Explaining a low-pass gate (LPG) 2:06 Starting with a low-pass filter 2:35 AR envelope 3:01 Modifying the envelope 4:25 Multiplication 5:14 Subtraction 6:12 Switching to 1-pole filter 7:26 Resonance (not usual for an LPG) 8:21 Talking through the macro
Part 2, where I actually make the sequencer, here:
A Pure Data interactive system that plays hardcore drumbeats when it’s not receiving any audio input.
At the start of winter break, I wanted to make some music and burn off some steam. The “Interactive Hardcore Music System” was the perfect solution for both. Here, I talk through the Pure Data patch explaining how it works and how I’ve used it, and waxing philosophical about how things don’t need to be complicated to be sophisticated (and musically expressive).
Get the “Benjolin Synthcore” album on bandcamp:
More Pure Data Tutorials on YouTube:
0:00 Intro/What is this thing? 1:41 Input section of the patch 4:30 Interaction with Logic Pro X 4:53 Compression as secret sauce 6:03 Creating the beat (probability gates) 7:34 The results 8:13 Other examples 9:25 Closing: Sophisticated ≠ Complicated
Creating an ambient music machine in Pure Data Vanilla with a “clamping VCA” that adds subtle distortion, imitating the envelopes in Roland TR-808.
I made a clamping VCA in Reaktor a few weeks back, and now here’s another example in Pd. Normally, amplitude envelopes in synths are a control envelope on the amplitude of the signal. When we use a “clamping VCA”, though, instead of controlling the amplitude of the waveform, we clip it at the desired maximum envelope. This means, when the VCA is all the way up, it sounds the same, but during the attack and release, we’ll get the addition of subtle (or perhaps not-so-subtle) distortion to our waveform.
I use [clip~] in Pd to achieve this effect, stealing the idea from Noise Engineering’s “Sinclastic Empulatrix” module, which, in turn, stole the idea from from the Roland TR-808 drum machine’s cymbal envelopes.
Using the latency from videoconferencing software as a delay for feedback loops, this time with Kyma 7 processing the signal at both ends, creating (noisy) evolving sonic textures.
During the pandemic, conferencing software quickly became a required part of work and education culture.
Of course, this technology’s ability to keep us connected has been and important part of keeping people safe, but we’ve also discovered the quirks of this mode of communication. Being bound to this remote interaction inspires curiosity about its potential for collaborative creativity. Musicians have know for a while about the issues of internet latency in coordinating remote ensembles, but what if, instead of attempting to recreate the conditions of a traditional performance in this new medium, we embraced the “space” created by this conferencing software?
In this performance, the audio signal is sent between the two Kyma systems, creating a feedback loop.
Feedback loops, such as when we put a microphone close to a speaker, emphasize the resonant frequencies—the imperfections—of a system. As we know, the audio of conferencing software is an imperfect connection, with latency, filtering, and audio compression artifacts.
This conferencing-software feedback loop, then, emphasizes these imperfections, bringing out the character of this communication medium as an emergent soundscape.
Doing some live processing of sleigh bells in Pure Data to create an “Interactive Holiday Noise Music System.”
Since it’s mid-December, let’s make some holiday music. If you’re sick of the standard cloying Muzak fare, though, you can make your own feedback delay sample-crushing interactive music system in Pure Data in an afternoon.
The main point here is getting a “trigger” from audio input crossing a loudness threshold. Once we have that trigger, we can use it to make changes in live-processing of a sound and trigger other sounds too. This is a simple idea, but its effectiveness is going to depend on what these changes are and how we play with the system.
0:00 Demo 0:26 Introduction / Goals 1:23 Input Monitoring 2:41 Direct (“Dry”) Output 4:08 Feature Extraction with [sigmund~] 6:55 Amplitude as Trigger 8:43 Triggering Changes in Delay 12:44 Sample-Crushing 17:03 Triggering an Oscillator 19:37 Oscillators into Harmony 23:35 Putting it all together 25:33 Closing Thoughts
Building a “clamping VCA” in Reaktor for subtle distortion, imitating the envelopes in Roland TR-808.
Normally, an amplitude envelope for your synths are just that: a control envelope on the amplitude of the signal. When we use a “clamping VCA”, though, instead of controlling the amplitude of the waveform, we clip it at the desired maximum envelope. This means, when the VCA is all the way up, it sounds the same, but during the attack and release, we’ll get the addition of subtle (or perhaps not-so-subtle) distortion to our waveform.
I use the “Mod. Clipper” in Reaktor 6 to achieve this effect, stealing the idea from Noise Engineering’s “Sinclastic Empulatrix” module, which, in turn, stole the idea from from the Roland TR-808 drum machine’s cymbal envelopes.
0:00 The “Mod. Clipper” 0:33 Clamping VCA 1:25 Simple Sine Oscillator 2:03 Mod-Clipping the Sine Wave 3:51 Standard VCA for comparison 4:58 Pulse Wave 5:41 Sawtooth Wave 6:34 Adding a Filter 7:35 Next Steps