How to Make Interesting Generative Music

[rofilm]

After more than 40 years of workingwith modular synths I´ve got the idea of writing down my experiencesand the knowledge that I´ve gained over the years and produce ane-book trilogy about how to make generative music. The first twovolumes are finished, some hundreds of page, legions of videos andpresets, and right now I´m working on volume 3 of the trilogy.

I think that generative music is animportant part of working with modular synths, perhaps one of themost important ones. Therefore I´ve decided to make the main ideasand techniques of my work public – not everyone can afford to buythe books.

I´m going to rework volume 1 into aseries of articles / posts and will even add most of the videodocumentation, and I hope you´ll find my posts interesting andperhaps they will initiate an in-depth discussion of the matter.

And that´s what I´m going to writeabout here (I´ll try to post one article per week):
(more about it all on my websitehttps://dev.rofilm-media.net)

Enjoy your day!
Rolf


Chapter0: About This Course And Some Words About
WhatGenerative Music Is
Chapter1: Real Randomness vs. Complex Cycles
(andthe combination of both)
Chapter1.1: LFOs
Chapter1.2: Other Devices Generating Regular
Cycles
Chapter1.2.1: Looping Envelopes
Chapter1.2.2: Sequencers
Chapter1.2.3: Shift Registers With Feedback
Chapter1.2.4: Sequential Switches
Chapter1.2.5: The Turing Machine – Part 1
Chapter1.2.6: Samples and Recordings
Chapter1.3: Randomness, Probability and
Stochastic
Chapter1.3.1: Some Basic Definitions
Chapter1.3.2: Sample & Hold
Chapter1.3.3: A Short Glimpse at the Turing Machine
Andat Shift Registers Again
Chapter1.3.4: Perfect Pseudo Randomness:
GrayCode Modules
Chapter1.3.5: Imperfect Pseudo Randomness:
EuclideanSequencers
Chapter1.3.6: Random Trigger (Percussion) Sequencers
with Different Amounts of Randomness
Chapter1.3.7: Stochastic Sequencers
Chapter1.3.8: Probability Gates
(RandomClocked Gates)
Chapter1.3.9: Bernoulli Gates

Chapter 2: What to Modulate And to Trigger
Chapter 2.1: Pitch
Chapter 2.2: Timbre
Chapter 2.2.1: Filter
Chapter 2.2.2: Shapers
Chapter 2.2.3: Partials (additive)
Chapter 2.2.4: FM/PM
Chapter 2.3: Voices
Chapter 2.4: Rhythm
Chapter 2.5: Effects
Chapter 2.6: Envelopes
Chapter 2.7: Quantizers
Chapter 2.8: Grains
Chapter 2.9: Sample (Player)
Chapter 2.10: Slew Limiter
Chapter 2.11: Comparators
Chapter 2:12: Pitch Shifter
Chapter 3: Compositional Aspects of Generative Music
Chapter 3.1: General Thoughts, Strategies And
BasicCompositional Decisions
Chapter 3.2: Basic Compositional Techniques
Chapter 3.2.1: Contrasting
Chapter 3.2.2: Repeating, Modifying and
InvertingRelations
Chapter 3.2.3: Basic but Exclusively
GenerativeTechniques
Chapter 3.3: Specific Compositional Techniques
Chapter 3.3.1: Pitch Dependency
Chapter 3.3.2: Rhythm
Chapter 3.3.3: Tension and Layers
Chapter 3.4: Certain Patch Techniques
And Examples
Chapter 3.4.1: Switching Voices and Larger Parts
oft he Patch
Chapter 3.4.2: Sculpture Randomness and
SettingBorders
Chapter3.4.3: Jumping between certain BPM and
Inverting Pitch Lines
Chapter3.4.4: Mixing Stable and Random Elements

Chapter 4: Some Building Blocks of Generative Patching
Chapter 4.1: The Instrumentation of Envelopes
Chapter 4.2: 5 Faces of Randomness
Chapter 4.3: Random Harmonies

 

[rofilm]

Welcome to part 2 of thisseries of articles taken from the e-book (seehttps://dev.rofilm-media.netfor some background information). Today we start patching, and I haveintegrated even video in this article to make things audible andvisible.

Chapter1:


RealRandomness vs. Complex Cycles


(andthe combination of both)​

​

Chapter1.1:


LFOs​

Whenwe hear “permanently changing” most of us will surely think ofsample and hold units at first.


And,yes, S&H units are important engines to drive our generativepatches. But what about clock generators and LFOs (the latter beingable to serve as clock generators as well)?


“Why,LFOs generate regularly repeating cycles?” you may say. And: “Nopermanently changes will be going on. All changes repeat exactly thesame way, when the next LFO-cycle starts.”


Youare true. Of course you are. But such LFO cycles can be quite longones. The lowest frequency of the VCV rack LFO-1 for example is0.0039 Hz, which means a cycle of 4 minutes and 16 seconds beforethings start repeating again. And there are LFOs with even lowerfrequencies and longer cycles out there. But even 4 minutes may giveus – as listeners – at​

leastthe illusion of “permanently changing”.


Yournext argument will be:


“Butthese changes are going on THAT slowly, that the result is boring atthe least, and some of our listeners may even think, that there areno changes at all.”


Andyou are true again. But if my LFO is equipped with a CV-in jack tomodulate its frequency, well, then things start to get interesting.





Inother words: let´s talk about frequency modulating LFOs, aboutmodulating the modulation strength (the “volume” of an LFO´soutput), about feedback loops consisting only of LFOs, and aboutadditive mixing of different LFO outputs.
​

Youcan imagine what complex networks we can build with these fourbuilding blocks.





Andif we use different LFOs of such a network to modulate or triggerdifferent sources of sound, we are able to construct a “super-cycle”(which consists of a set of “sub-cycles”) that lasts a very longtime until it returns to its beginning.





Andwhen we further take into account, that frequency is not the onlyparameter, which we can modulate, things get really exciting:modulating the LFO´s amplitude, the LFO´s phase and even the LFO´swave shape (if our LFO is equipped with a CV in jack allowing us tomodulate the shape).​

Asimple example shall explain what I mean:


Let´stake two LFOs, LFO A and LFO B. LFO A runs at a frequency of 0.03 Hz,which is a cycle length of 33 seconds. LFO B runs at 0.04 Hz, whichleads to a cycle length of 25 seconds.


LFOA modulate the frequency of a VCO, let´s call it “VCO X”, andLFO B modulates the frequency of a VCO called “VCO Y”. We can usetwo quantisers and two VCAs to make things more comfortable to hearand to listen to.
​

Let´snow say, that both LFOs start their first cycle at the same time.





Touse the aforementioned terms: we have one “super-cycle”consisting of two “sub-cycles”.





Pleaselook at the following table now: it lasts all in all 825 secondsuntil both LFOs begin their cycles at the same time again. LFO Aneeds 25 cycles to get there, and LFO B needs 33 cycles.


Thelength of our “super-cycle” is 825 seconds, even if the“sub-cycles” are only 25 seconds and 33 seconds long.





Thevideo “Video C1_1 SupercycleVideo” (just follow the link:) demonstrates the patch.


Wellthen, let´s set up some typical LFO networks now.
​

Theeasiest group of LFO networks – easy in terms of predictability –are additive ones, networks in which all LFOs work parallel on oneand the same (ore more than one) modulation target. Let me start with1 VCO as the target and 2 modulating LFOs. In those cases theabsolute values of the LFOs add to each other: when the phase of thewaves of both LFOs are positive the sum is a higher positive one, ifboth are negative the sum is a higher negative one, and if one waveis in its positive phase, the other in its negative phase, then weget a subtraction, and in case the waves differ by 180°we get a complete phase cancellation.



​

Theresulting summing wave may look like in the following picture (justan example). And patching a quantizer between the LFOs and the VCO weget the following melody (given that we have chosen the outputstrenght of the LFOs adequately (later more about adequate modulationstrengths).
​

Inthe region marked in yellow the patch will play


h2-#a2-a2-#g2-g-#f2-f2(will be held for a while given, that the local minimum is stillnearer to f2 than to e2) and then continue with#f2-g2-#f2-f2-e2-#d2-d2-#c2-c2#c2-d2-#d2-e2-f2 (will be held for awhile again) and then back to e2-#d2-d2-#d2-e2-f2





Withboth LFOs running at different frequencies we get random soundingmelodies with patches like that one.





Usinga suitable mixer for the two LFOs we can adjust the wanted frequencyranges by adjusting the “volume” of the LFOs – what isadjusting the Cvs, which are sent by the LFOs.
​

Andwe can – of course – adjust the LFO output strength differentlyfor both LFOs.





Ifthe channels of our mixer are equipped with CVins, we can modulatethe relative strength of each LFO by other modulation sources –e.g. using more LFOs. And if our mixer doesn´t have CV ins, we canpatch VCAs between each LFO and the mixer.
​

ButI´m anticipating what will be talked about later.


Thefollowing link leads you to a video, which shows me messing aroundwith the patch (and explaining a bit more about it). In the video I´musing other LFO waves than only sine waves as well.








Letme add a third LFO. But instead of just another sine wave this newLFO shall produce a square wave, a wave that simply jumps between twovalues. We will have to attenuate the output of this LFO a lot toavoid long periods of silence, when it´s at its low level.
​

Witha patch like that we get “unexpected” jumps in the melody, whichhad been simply going up and down so far – continuously up and down– and the only “randomness” was in the different lengths of therises and falls.


Andwith this third LFO, which – or course – runs at a thirddifferent frequency, the overall length of the aforementioned“super-cycle” increases dramatically, which increases theimpression of randomness even more. With frequencies of 0.025 Hz,0.035 Hz and 0.25 Hz our “super-cycle” gets a length of 1,160seconds, what is nearly 20 minutes. Surely long enough to cause theimpression of real randomness.


Thevideo, which is hiding behind the following link demonstrates (andexplains) the patch in detail.








Inthe next article I´ll leave the field of purely additive combinedLFOs, build up some rather complex networks and introduce a generalLFO block system to make it easier to construct and to document LFOnetworks of infinite complexity.





…tobe continued
​

 

[prodbyedren]

Dope thank you