Going with the Grain

Oct 1, 2008 12:00 PM, By Dennis Miller

           
 

TEN GRANULAR-SYNTHESIS PROGRAMS TO SLICE AND DICE YOUR SOUNDS

Judging by the number of hits you get when you Google it — several hundred thousand — granular synthesis would appear to be a very hot topic. You can also measure its popularity by looking at the large number of programs that either are dedicated to granular synthesis or include it as a feature. Though it's not the best way to produce cutting lead lines or thumping bass parts, granular synthesis has a vast range of musical uses, including slowing down sounds without changing their pitch, adding reverb or other ambient qualities to a sound, and, of course, producing all manner of amorphous sonic textures.

Granular synthesis is a technique intended to create clouds or clusters of small sonic events called grains (see “A World in a Grain of Sound” in the November 1999 issue, available at emusician.com, for an introduction to granular synthesis). Grains are typically in the realm of 5 to 100 ms long and are created from either synthetic waveforms or samples. When clumped into massive groups, individual grains are virtually indistinguishable, but the overall impression can be like rain or falling rocks, or more rhythmic, even pitched sounds, perhaps with recognizable bits of a source sample popping through.

In this article, I'll cover representative programs from the world of granular synthesis. Many dozens of programs support the technique, and the ten chosen for this roundup are just examples of what you'll find if you go looking. I'll focus only on software, acknowledging that hardware-based systems such as the Symbolic Sound Kyma System are extremely capable in this area. There are also hundreds of Native Instruments Reaktor patches that employ granular synthesis, not to mention patches designed for Csound, James McCartney's Super Collider, Cycling '74 Max/MSP, and other programming environments, so be sure to check out their users forums if you own any of those programs.

The programs I'll look at are Sinan Bökesoy's Stochos V6, CDP GrainMill 1.1, Karlheinz Essl's REplay PLAYer 3.2, Nicolas Fournel's Granulator 1.1, Tom Gersic's Atomic Cloud 1.0, Nikola Jeremic's Organik 1.2, Christopher Keyes's Granular Cloud Generator 2003, LowNorth RTGS-X 2.4, Stefan Smulovitz's Kenaxis 2.2, and Jörg Stelkens's crusherX-Live 3.51. (See the sidebar “Manufacturer Contacts” for contact info on each program and the sidebar “Other Options” for a list of some granular apps that are not included in this article.) I won't go into detail on the sonic results each can produce, so be sure to check out the Web Clips and, where available, the demos for each program to get a sense of the sounds it can make.

In View

The granular-synthesis programs covered here share a number of features, though as you might expect, each also has its own take on the technique. All of the programs except GrainMill produce audio in real time in response to user input, and all except Stochos can record output to disk. All run as standalone applications, but Organik also includes a VST plug-in version. (CrusherX-Live includes a VST Bridge component that you load in a host if you want to use the program as a plug-in.) All but Organik let you load samples for granulation, and crusherX, Granular Cloud Generator, Organik, RTGS-X, and Stochos include one or more synthetic waveforms for use as grain sources. CrusherX, Kenaxis, and RTGS-X allow you to granulate real-time audio input.

Flexible granular synthesis involves controlling aspects of both individual grains and overall granular textures (often called grain clouds), and all of the programs have capabilities of those types. For example, you can modify both the pitch (frequency) and duration of individual grains in all the programs. Most of the programs use common and intuitive increments for these two parameters — hertz or MIDI Note Number for pitch and millisecond for grain duration — but Granulator only provides a range of 0 to 127 for both of these controls, with no indication of what precise values that span represents, and Atomic Cloud's controls read simply “0 - 100.”

The range of available grain durations varies quite a bit, with some of the programs providing a more limited range than others. Organik, for instance, tops out at 80 ms for maximum grain duration, while Kenaxis and Stochos have no limit on the length of grains. GrainMill's maximum duration is 3.2 seconds, but the actual size you get depends on the size of the source file (see Web Clip 1). Its minimum size is fixed at 12.5 ms. As for all its parameters, GrainMill lets you apply a simple linear envelope to vary the value over time or build complex multisegment envelopes for that purpose (see Fig. 1). Note that grains of 1 second or more tend to retain the characteristics (pitch and timbre, for example) of their source. That could be an appealing creative option if, say, you're working with speech and want to retain some semblance of the original text.