Reaktor – Simon Hutchinson

4 February 20254 February 2025

Karplus-Strong Synthesis in Reaktor Primary

Patching up a Karplus-Strong synth from scratch in Reatkor 6 Primary.

Karplus-Strong synthesis is a digital synthesis technique that simulates the sound of plucked strings by using a feedback loop to model the behavior of a vibrating string. Developed by Kevin Karplus and Alex Strong, this method generates resonant waveforms by feeding back a short noise signal through a filtered delay line with feedback.

In this video we build a simple K-S synth from scratch in Native Instruments Reaktor 6, exploring what happens based on the design decisions that we make. By the end of this video, you should understand both the theoretical concepts and practical implementation in Reaktor, giving you a unique tool for your music production arsenal.

Check out more intermediate Reaktor Tutorials here:

10 June 2024

Reaktor 6 Matrix Mixer

Building a matrix mixer in Reaktor 6 primary, and then exploring its possibilities for sound design.

I’ve been a little obsessed with matrix mixers lately, because they feed my desire for unique sound design applications (and feedback). A matrix mixer is a combiner module that can route multiple inputs to multiple outputs, often allowing you to adjust how much of each input signal goes to each output. While sophisticated, they’re pretty easy to build in Reaktor or other software, and can maybe be useful for some next-level synthesis applications.

0:00 Intro / Why Matrix Mixers?
1:18 Starting the Build, Simple Sine Oscillator
2:50 Matrix Mixer Macro
3:55 Visible Ports for Panel Patching
5:37 First Mixer of the Matrix
9:46 Duplicating It for the Matrix
10:48 Matrix Mixer Basics
12:05 Delay and Feedback
15:29 Adding a Second Delay
18:44 END OF LESSON. Unless…
19:59 Adding Ring Modulation
21:43 Building a Complex Patch
24:45 Other Examples of Implementation
25:58 Final Thoughts, Next Steps

Beginning Reaktor 6 Tutorials:

28 November 2022

Clamping VCA in Reaktor 6 Primary

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

Thinking Beyond the ADSR, Other Envelope Generators in Reaktor 6 Primary

Adding envelopes to our synthesizer that aren‘t an ADSR.

ADSRs might be the envelope generators that we encounter most often, but they’re not the only way to shape our sound. There are a number of other musical ways to craft change in our synthesizer over time with these non-periodic TVCs.

Let’s check out what other options there are in Reaktor 6 primary.

0:00 Intro, not just ADSRs
0:24 Simple saw for testing
1:24 AR Envelope
2:47 AD Envelope
4:48 ADR
6:33 ADBDR
9:25 ADBDSR
10:41 AHDSR
12:20 Next steps

“Hard Sync” Oscillators in Reaktor 6 Primary

Creating retro sounds with hard-synced oscillators in Reaktor 6 Primary.

“Hard sync” is synthesis technique that uses two oscillators: when one oscillator (the “leader”) finishes a cycle, it resets the period of the other oscillator (the “follower”), creating a period at the frequency of the leader, but a timbre from the incomplete cycles of the follower.

This is a really easy way to create original, complex sounds, using just two oscillators.

I say “1980s”, here but check out this sound in the Cars 1979 hit, “Let’s Go” (played on a Prophet-5 Synthesizer).

0:00 Defining “Hard Sync”
0:38 Building a Single Oscillator
1:35 Adding the “Follower”
3:03 Changing the Pitch Relationship
4:40 That Hard Sync Sound
4:57 How it Works
6:30 Follower Lower than Leader
7:25 Adding an Amplitude Envelope
8:10 Adding a Filter (for a bit)
9:28 Closing, Next Steps

Reaktor 6 Beginner Tutorials here:

11 July 2022

Patch from Scratch: Reaktor Feedback Loop

Building a dynamic feedback loop in Reaktor 6 Primary.

Here’s a simple patch based off the work of composer/engineer Jaap Vink from the Institute For Sonology, Utrecht. This ensemble is a feedback loop with a delay, a ring modulator, and a saturator (with a simple sine as a “trigger” to get things started).

Each pass through the loop, the signal is delayed, then ring-modulated, significantly changing the spectrum. This can devolve into noise rather quickly, but a soft touch can lead to some interesting evolving soundscapes.

There’s no talking on this one, just building the patch, and listening to it go.

More Audio Cybernetics and Feedback:

30 May 2022

This Fundamental Frequency Is an Illusion

All sound can be broken down into individual frequency components, and the lowest frequency component of a sound is called the “fundamental” (all the frequencies above that fundamental frequency are the “partials”). By cleverly setting the relationships of the amplitude and frequencies of the harmonic spectrum, though, you can trick your ear into hearing the pitch of a sound as an octave below the lowest frequency component.

Here, I’ve built a quick demo in Reaktor 6. Listen and see what you think.

Adding “Analog Warmth” to Your Digital Synth (Reaktor 6 Primary)

Some ideas on how to add some beautiful (analog?) imperfections to your Reaktor synths in Reaktor Primary.

The definition of “analog warmth” is pretty nebulous, but it brings to mind things like tube distortion and tape saturation–imperfections to the “fidelity” of the sound. Digital sound has imperfections too, of course, but these are aesthetically different (though perhaps no less interesting). In this video, though, I talk about some ideas in how to imitate the imperfections of analog in our digital Reaktor 6 synths.

Reaktor 6 Beginner Tutorials here
More Intermediate Reaktor Tutorials here.

21 March 2022

Reaktor 6 Easy Portamento / Pitch Glide

A super-quick video on adding portamento to your Reaktor synthesizers and the theory behind it.

Portamento is a glide between notes, so, rather than jumping from pitch to pitch, we have an uninterrupted, continuous connection between the notes. Since we know our low-pass filter “rounds off” our audio waveforms, let’s see what happens when we apply that to our pitch control data.