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In the World of Grains – Part 8

granular synthesis

In the World of Grains – Part 8

(contains embedded video – excerpt from my e-book about sonic grains: https://www.dev.rofilm-media.net/node/332). If you want to support my work, please make use of the "PayPal" button - thank you very much indeed!

I´m a big fan of practical approaches, and suggest the following schedule, well knowing, that each individual category needs a lot of further investigatons. But it may well serve as a first orientation, and as a stable fundament to build your own systematic in more detail.

  1. sine waves

  2. pulse waves of different duty cycles with subcategories of different filter attachments)

  3. triangle waves with subcategories of different filter attachments

  4. saw waves with subcategories of different filter attachments

  5. noise with subcategories of different filter attachments

  6. complex synthesized sounds with subcategories of used basic waveforms 1.-4., and a short description of the synthesis method

  7. extracts from recorded musical instruments with subcategories of different recorded instruments, as well as the lowest, the highest, and the average frequencies in the extract

  8. extracts from recorded voices with subcategories of male, female, and children, as well as the lowest, the highest, and the average frequencies in the extract

  9. extracts from recorded wildlife with subcategories of the kinds of animals, as well as the lowest, the highest, and the average frequencies in the extract

  10. extracts from recorded sounds of nature with subcategories of the kinds of natural events (rain, river...), as well as the lowest, the highest, and the average frequencies in the extract

  11. Extracts from recorded machine sounds with subcategories of the kinds of machines, as well as the lowest, the highest, and the average frequencies in the extract

granular synthesis

You may find even more categories, or a different schedule according to your individual needs. All in all we could categorise a grain by the following “personal description”:

a. duration in ms

b. duration in percentage of the longest contained wavelength, with 101% and more meaning at least one complete cycle fits in the grain´s lifetime

c. grain window

d. grain´s origin (1. - 11.)

granular synthesis

Well, so far the level of single grains. Now for the level of groups of grains, of clusters. Those of you, who like to go deeper and increase their studies shall be warned of an ambiguity in literature: some authors use the term “cluster” as a synonym for “texture”, whereas others think of larger structures, when talking of “texture”.


The first new – and obvious – parameter when entering the level of clusters is a cluster´s density, the number of grains, which are sounding at the same time. Some authors describe the number of grains, which are generated per time unit (e.g. per second) with the term “density”. I don´t agree with that view, because it leads us into a number of problems.


Every progression of sonic events in time is a rhythm, regular or irregular. Rhythm is a compositional aspect. Defining “density” by saying (e.g.): “1 grain per second” is talking about a property of the (whole) composition, the whole musical work (or at least a macroscopic part of it), and doesn´t categorise the (microscopic) material, the piece is composed of.


Classifying a cluster does need to take into account, that there are time-dependent aspects. Sure. But “time-dependent” doesn´t mean “repeatedly”. Defining “cluster” as a grain-per-time unit forces us to talk about “how” grains repeat over time, forces us to talk about things like synchronous (regularly) or asynchronous (irregularly, without a noticeable pattern) granular synthesis, which abducts us from categorising microstructures far into the land of composing (which is going to be the matter in chapter 4).


The situation “number of generated grains per time-unit” can include “only one grain every x (milli)seconds” - and we are back to the attributes of single grains. To say it again: I´m not (not yet) talking of making a composition, nor of finding some systematics or rules of doing so, but I´m (still) only talking about a possible system of categories of grains and short granular structures. It´s like making a list of (classic) acoustical instruments and instrumental groups, and describing their character. It´s not about writing the whole score these instruments will have to play. mWell, back to density of a cluster as the number of grains, which can be heard at the same time. In his article “Introduction to Granular Synthesis” (in Computer Music Journal vol. 12 no. 2 from 1988) Curtis Roads names the following 12 properties of what he calls an “event” (which is not the same as a “cluster”)

  1. Beginning time

  2. Duration

  3. Initial waveform

  4. Waveform slope (he means the transition rate between different waveforms)

  5. Initial center frequency

  6. Frequency slope (as he talks about simple waveforms like sine, pulse etc. it´s possible to describe, how the change of frequency is developing)

  7. Bandwidth

  8. Bandwidth slope

  9. Initial grain density

  10. Grain density slope

  11. Initial amplitude

  12. Amplitude slope

granular synthesis

I suggest using the event properties Duration, Bandwidth, Bandwidth slope, Initial grain density, and density slope also to categorise a cluster. The property “Initial waveform” will need a more detailed description, when we use more complex sonic content, more complex than the standard waveforms sine, square, saw etc. The Beginning time is – again – an aspect of the whole composition (where in the composition does a certain event start). Instead of only one frequency property I suggest using two, namely the lowest frequency in the cluster and the average frequency of the cluster (given, that I know these from categorising the individual grains, that build the cluster). Therefore there will be also two frequency slopes to take into account. Amplitude! Amplitude is systematically more complex a thing, than it seems at first view. On one hand it seems to belong more to the region of composing, as amplitude isn´t an inner property – a violin is a violin, no matter how loud it is played (ok, things like the pressure of the bow on the strings determines the sound as well – no example fits 100%, does it?) , and the “cluster” of bowed string instruments in an orchestra stays the same, independently from the amount of amplitude they produce – on the other hand there is a direct dependency between density and amplitude: the amplitude increases with the number of simultaneously sounding grains.

As long as the cluster contains only grains of the same kind we won´t need the property of amplitude, because it directly results from the density. But with inhomogeneous clusters containing different kinds of grains the parameter of amplitude gets meaning on behalf of our categorising work. Let me use the string example again. One and the same string ensemble sounds differently, when the amplitude, which is produced by an individual member of the ensemble changes in relation to the volume the other members produce. What we need to determine is how amplitude is distributed, is spread across the different kinds of grains in a cluster. In the next article I try to find an even more practical approach.

to be continued

to part 1: ("A Short History of Granular Synthesis - Part 1"):https://www.dev.rofilm-media.net/node/340

to part 2: ("A Short History of Granular Synthesis - Part 2"): https://www.dev.rofilm-media.net/node/342

to part 3: ("A Short History of Granular Synthesis - Part 3"): https://www.dev.rofilm-media.net/node/346

to part 4: ("A Short History of Granular Synthesis - Part 4"): https://www.dev.rofilm-media.net/node/356

to part 5 ("In the World of Grains - Part 1"): https://www.dev.rofilm-media.net/node/364

to part 6 ("In the World of Grains - Part 2"): https://www.dev.rofilm-media.net/node/373

to part 7 (“In the World of Grains – Part 3”): https://www.dev.rofilm-media.net/node/378

to part 8: (“In the World of Grains – Part 4”): https://www.dev.rofilm-media.net/node/385

to part 9: (“In the World of Grains – Part 5”): https://www.dev.rofilm-media.net/node/390

to part 10: (“In the World of Grains – Part 6”): https://www.dev.rofilm-media.net/node/398

to part 11: ("In the World of Grains - Part 7"): https://www.dev.rofilm-media.net/node/407

to part 12: ("In the World of Grains - Part 8")   https://www.dev.rofilm-media.net/node/414

to part 13: ("in the World of Grains" part 9)  https://www.dev.rofilm-media.net/node/421


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