FUNDAMENTALS IN SYNTH PAINTING - Part 1: Getting the most out of Operator with DJH

In this Lux Cache tutorial series, we dive into the essential components of synth painting, training the ability of being able to create the sounds that are in your head. In this tutorial, industrial club sound architect DJH goes over the functionalities, idiosyncrasies and unique approaches towards generating inspiring sounds with one of Ableton Live`s longest-standing stock instruments: the Operator synth. Along with this tutorial, DJH provides a pack of presets for Ableton’s FM synth, as well as a sample pack featuring all the sounds created in this tutorial.

This tutorial is available as both a Patreon text post and .pdf document format . We ask you kindly to not share Lux Cache content outside of the Patreon, our contributors rely on your donations.

All preview sounds/clips mentioned in this tutorial can be found in this private SoundCloud playlist or this accompanying Google Drive folder.

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Preface

Often overlooked in favor of its more recently implemented cousin Wavetable, I still find Operator´s stripped back, intuitive approach to synthesis utterly inspiring and surprisingly useful in yielding inspiring and varied sonic results. Ironically, I found myself returning to Operator in an increasing frequency the more external VST synths I've acquired over the years, cherishing its simplicity and excellent implementation into the Live UI ecosystem despite the fanciful Interfaces and expansive sonic possibilities of recent developments in soft-synth technology has to offer.

I hope this tutorial and the provided presets will inspire readers to engage and experiment with the stock-tools in Live and maybe discover some novel features and tricks they weren't quite aware of. I know that this tutorial is limited in its scope, exclusively focusing on Live and it´s native Operator-synth, but I'm aware of similar instruments existing within the stock libraries of other DAWs,(EFM1 in Logic,Sytrus in Fl Studio), and would be more than willing to write a follow-up guide attempting to transfer the approaches and techniques described here to those synthesizers’ distinct workflows.

FM Synthesis

I won't go into the nitty gritty details of FM-synthesis here since one could write an entire book worth of elaborations on it’s myriad of implementations and use cases.

The initial algorithm that most of today’s FM synthesis-implementations are based upon was developed by John Chowning in the 1960s and subsequently licensed to Yamaha who started releasing their first generations of digital FM-synths in the 1980s.

Basic Concepts: Algorithms, Carriers, and Modulators

The fundamental concept of FM synthesis lies in the idea of changing an oscillator’s frequency in accordance with the amplitude of another modulating signal. In the digital domain this is most commonly implemented via phase modulation.(I am by no means a mathematician or engineer so feel free to go down multiple google rabbit holes if you have further interests in these concepts since there are people out there who can explain these concepts more clearly and elaborately)

In my intuitive understanding of FM-synthesis, the concept of an oscillator in which frequency is modulated by a LFO that gradually increases in frequency has been very helpful to grasp how sounds are generated in an FM-context. Notice how the audible vibrato effect gets replaced by high encroaching high-frequency overtones when passing a certain threshold of LFO speed.

🔈🔈🔈🔈 Slowly increasing frequency modulating LFO into audio rate

These sidebands are elemental to FM-synthesis and can be controlled via the frequencies and respective volume envelopes of the modulating oscillators.

The oscillators’ relation to each other is,(in the case of Operator and an array of famous FM synths), determined by a preconfigured routing constellation that is referred to as an Algorithm.

The Oscillator that is routed to the output of the synthesizer is called carrier oscillator, while the oscillators modulating its frequencies are referred to as modulators. Different algorithms can present users with wildly different results while maintaining the same initial Oscillator Settings.

Basic Concepts: Coarse Pitch, Amplitude, Fine Tuning, Amplitude

FM Synthesis generates Sounds based on the frequencies of interconnected modulator  and carrier signals. In Operator and many other commercial Fm synths, the Frequencies of the individual oscillators are linked to integer multiples of the played frequency, influencing the frequency content of the output according to the harmonic series. In Operator, this multiplier is referred to as Coarse Pitch and can be further modified by a Fine-tuning knob, proving to be especially useful when synthesizing bell-like timbres and more abstract, natural soundscapes.

🔈 Example: Mellow Bell Timbre

🔈 Example: Plucky Bell Timbre

🔈 Example: Evolving Texture while swapping through algorithms

Shaping the Amplitude of individual modulators is vital in achieving interesting timbres with FM synthesis. Operator offers you several familiar parameters to shape it’s ADSR envelope with,(and several other more esoteric features which I will get into later).

Adjusting Amplitude Envelopes of modulators can result in dramatically different sonic results for the same configuration of Oscillator tunings, turning plucky Marimba-esque sounds into metallic stingers or disjointed pads or something in between on a whim.

Operator: Going Deeper

In addition to the basic functionalities of an FM-synth that were briefly laid out above, Operator features a variety of unique/unusual parameters that go beyond the scope of classic Hardware FM-synths such as the DX-7.

To not further boggle down the article with boring theoretical concepts, this section will be more praxis-oriented in that it will feature my usual approaches to employ the features in question to achieve interesting results concerning both abstract sound design and the creation of instrument patches.

Built in Oscillators and Custom Oscillators

While traditional FM-synths only used pure mathematical sine waves as oscillators, Operator provides you with the ability to approximate a variety of waveforms such as saw- square and triangle-waves using a bank of up to 64 individual sine waves per oscillator.

Use the 3 buttons to the right of the sinebank to toggle between 3 different magnitudes(16,32,64).

Right clicking will open a context menu which allows you to toggle between editing either all partials or exclusively focusing on even harmonics,(more “pleasant sounding, great for adding subtle upper harmonic content to basses),or odd harmonics,(great for more natural sounding timbres which require a hint of dissonance to appear believable, especially bells/flutes).

The Normalize toggle is on by default to prevent you from blowing out your speakers in the act of summing up 64 individual sine waves per oscillator, but i found that turning it off and chugging a clipper/limiter into the effect chain makes sounds appear a bit more punchy.

The use cases for this are as varied as they are fun.

Here I used the oscillator partial menu to draw in some subtle upper harmonics for an 808 sub. Even small amplitudes go along way, especially when smashing subs into distortion plugins

🔈 Slowly dialing in upper harmonics to enhance sub

Drawing in random higher harmonics and leaving the fundamental(first partial) out can be loads of fun and result in some crazy, “squelchy” sounds, especially when picking wildly different harmonics for each of the 4 oscillators and flicking through all the available algorithms while resampling the synth`s output.

🔈 Drawing arbitrary high harmonics while changing algorithms to generate textural glitches

Drawing partials in while recording can produce unpredictable results and make these jams very rewarding when recording long sound design “takes” to harvest particularly interesting passages from. I often end up creating everything from one-shot drums and stingers to long loopable textures from these FM-jams. (The methodology will be further elaborated upon in the following tutorial)

Operator’s LFO

Operator’s LFO section may not look incredibly special upon first glance but I found it to possess certain features that make it unique within the roster of Live’s stock synths.

By default, the LFO is routed to the pitch of Operator’s 4 oscillators and can be selectively toggled on and off by clicking on the numbers 1-4 in the LFO section. Another hardwired routing to Operator’s filter cut-off Frequency can be enabled by clicking on the “FIL” toggle which is disabled in the default configuration. The LFO is also capable of modulating a variety of other parameters selectable from the “DEST B” drop-down menu. Unfortunately, there’s currently no way to freely route the LFO to multiple parameters within the synth via a Matrix-like in Ableton’s Wavetable synth, a fact I would love to see addressed in a (fingers crossed) future update for Operator.

The control section allows you to choose the LFO’s speed and global modulation amount. In contrast to most of the other built-in Live Synthesizers which feature hard-capped LFO-speeds, Operator allows you to toggle between a “Low” and “High” Speed mode for its LFO, with the high-speed mode going up to 12,5 kilohertz, essentially rendering the LFO a fifth Oscillator and opening up additional avenues for shaping the synthesizers sound that go way beyond simple vibrato or pitch bend effects.

I often factor the LFO into my FM-jams, dynamically changing the routing to different Oscillators while adjusting the frequency rate. Only modulating a specific modulator’s pitch while disabling the routing to the carrier can introduce an additional layer of complexity into a sound. I also encourage you to play around with the DEST B drop-down and explore all possible routings. The SHAPER DRIVE and VOLUME destinations can result in gnarly ring-mod like sounds when paired with high LFO-rates while the FILTER MORPH destination,(given you changed the filter mode to Morph), yields organic and “wet sounds when modulated fast enough.

🔈 Modulating SHAPER DRIVE with high speed LFO

🔈 Modulating Filter Morph with high speed LFO

One of my favourite tricks for leads and pads is to put the LFO into high mode and use the NOISE waveform on a simple 2-3 sine wave setup, slowly automating the LFOs rate depending on the melodic. It results in a haunting vibrato-esque sound that constantly appears to be on the edge of being sucked in by a tornado of white noise. S&H(sample and hold) can also yield interesting sounds, especially when choosing the high rate setting

🔈 Sine Wave noise LFO jam, slowly increasing and decreasing lfo amount

Envelope Looping and TIME

Each individual Oscillator features an ADSR envelope that can be used to shape the amplitude. Especially for plucky bell like tones, playing with the decay and attack of one or several modulators is really exciting, as even little changes can result in pretty drastic departures from the original setup.
(audio example, bell pluck morphing into noisy pad via attack adjustment)
So far, so standard FM-synth.

However, Operators ADSR Envelope features 4 different additional modes that can be selected from a drop down menu on the lower left corner of the envelope view and enable the synth to go beyond the familiar concept of one-shot envelopes.

Envelope Modes:

Loop: Retriggers Envelope at the end of the decay phase (specified in milliseconds)

Beat:  Loops the envelope according to a specified time signature (1/16, 1/12 etc.)

Sync: Same as beat but synchronized to Ableton’s Global Transport while Beat operates non-quantized

Trigger: Ignores note off, similar to how drum pads behave in drum rack(useful when synthesizing drums from scratch and trying to aim for a consistent sound each time the envelope is triggered

Both the Beat and Sync modes are amazing for percussive synths and rhythmic timbres, especially when set to different time signatures on each oscillator, resulting in an unpredictable polyrhythmic interplay between carriers and modulators.

In terms of generating abstract sound design and organic textures, the Loop mode presented itself as nothing short of an epiphany when I first discovered it.

The fact that it loops the envelope according to the length of the decay time makes it really easy to set up a stack of modulators with arbitrary decay times and just hit record while playing with the Time knob to create ever morphing, unpredictable walls of sound that can sound surprisingly organic and varied. (make sure to turn down the sustain to 0 so the envelope loops around as soon as it reaches the terminal decay time)

🔈 changing time knob on a set of simple interlinked sine waves set to Loop mode

🔈 changing time knob on a set of simple interlinked sine waves et to loop mode and beat mode

🔈 changing time knob while going through different algorithms on a similar setup as before

🔈 changing time knob with pitch envelope set to loop-mode, run through vocoder and saturator

The Time knob, which is present in multiple Ableton devices,( Multiband Dynamics, Wavetable etc.), dynamically scales all envelope rates across the entire synth, including decay which determines the length of the envelope's looping cycle.
Especially sets of short envelopes with small decay rates can sound really cool when paired with automations of the Time knob, turning polyrhythmic beatings into walls of chaotic noise and vice versa. There’s no right or wrong when playing with this technique, just try different algorithms while messing with the Time knob and I can assure you that you will stumble on some interesting sounds and timbres

Fixed Mode, Static Oscillators, Exploiting Beatings

In addition to its regular mode in which the oscillator's initial pitch is determined by incoming midi notes and then dynamically scales according to the coarse and fine parameters, Operator features a fixed mode which can be toggled via the eponymous button left to the level-knob.

The coarse knob turns into a frequency dial which determines the frequency of the oscillator independent of incoming midi notes. The fine knob turns into a multiplicator which can be used to scale the oscillators frequency by a fixed set of numbers.

By default the multi knob is at 1 which leaves the oscillators frequency unchanged.

The Fixed Oscillator mode is great for a variety of use cases. On very slow multi-settings ,(0,01 and below), oscillators can be used as additional LFOs which can creep into audio rate on a whim.

Especially for drum synthesis, the fixed mode is perfect because it enables precise adjustment to a kick drums fundamental or a snare drums “body” frequency. (i will further elaborate on this in a future tutorial)

One of the more out there uses of Operators fixed Oscillator mode lies in its ability to reach extremely low frequencies that lie way below the hearing threshold of the human ear. While these waves are inaudible on their own, they can serve as a great tool to exploit the peculiarities and artefacts of distortion- and limiter plugins.
In this recording, I slowly dial up the level of a 8hz sine wave in an instance of Operator that sits in the same sub-group as the drum-loop. The sub-group has a generic Ableton Saturator on it.

🔈 crushing drum loop with deep sine wave

As the saturator gets hit with the low frequency information, the oscillator’s rate becomes audible as a “pulsing” pattern of distortion periodically eclipsing the drum loop, making the sound appear seemingly disintegrating / falling apart.

I enjoy sending random samples into a clipper while playing low frequency sine waves underneath and listening for interesting overtones in the resampled results.

This technique can yield especially beautiful results when paired with sv1’s brilliant approaches to organic sound designing via the Ableton Vocoder laid out in a previous installment of the Lux-Cache tutorial series.

3rd Party FM-Synths

Although this tutorial exclusively focused on techniques related to Live’s Operator, some of the broader concepts carry over to other commercially available FM-synths.

To conclude this tutorial I want to provide a list of FM-synths, both free and commercially available, that allow you to experiment with this exciting approach to synthesis if your DAW of choice happens to not be Ableton Live.

Dexed - Freeware synth, closely modelled after the Yamaha DX-7. A bit finnicky UI-wise, but a ridiculous amount of free preset packs makes up for that.

FM8 - Native instruments’ take on FM-synthesis, ridiculously deep Matrix with advanced envelope Looping that, while sacrificing it’s readability and sleekness, go way beyond Operator in some regards.

Sytrus - An FM-synth integrated into FL-Studio, also available as 3rd party plugin on Windows. Features an expansive matrix and an additive oscillator function similar to Operator’s.

EFM1, Retro Synth, ES2 in Logic - Although none of these Synths match FM8 or Sytrus in Terms of interconnectivity, they are still capable of producing interesting FM-timbres. For more info on the ES2 make sure to check out Christy Carey’s article from last month

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DJH is a music producer and sound artist based in Germany. His recent projects ‘Inflicter’ and ‘Unfinished Bizznizz’ are available on Bandcamp.

You can follow them on Twitter @DjHeroyn and Instagram @1djheroin1