Interface Nr 113 November 2007

In quarter three of 2007 I was interviewed by the Dutch magazine Interface about my DSP activities. The nr 113 November 2007 issue holds the result of the interview. Read (in Dutch) / See the pdf-version of the article (Made available by Interface).


Since many of you will not be able to read Dutch, I made a free translation of the interview text below. Keep in mind the reader of this magazine is not familiar with the Capybara-320 or Kyma.


To bad, they have written my name incorrect on the front cover and the index page as Christian. It should be Christiaan! I was also a little bit surprised to see a screen dump of a time-line in the article that I did not provide. The layout guy must have grabbed the image from the Symbolic Sound Corporation site (because it has some nice colors?).

Interview (free translation)


DSP programming for the Capybara-320.

Beautiful filters made in Holland.


If you really want to create your own sound or set-up, you will have to program everything yourself. There are companies around that can help with this task. Symbolic Sound Corporation is such a company; it can provide you with a development pack. Interface had an interview with programmer Christiaan Gelauff.


Written by Allard Krijger >


Creamware is offering a development pack for their Scope platform. This development pack will cost you +/- 5000 euros and then you are ready to start programming. We are not talking about making your own patches on the available plug-ins/synthesizers, but really programming these plug-ins yourself. You should be a skilled programmer to be able to perform this. Most of the stuff is programmed in programming language called C++.



Symbolic Sound Corporation, a less known company, is also offering a development pack, but then free of charge. This system consists of hardware and software. De software is called Kyma and the hardware is called Capybara-320, which is a big 19"-rack with up to 28 processors. A basic system has 4 processors and 96 MB of sample ram (error in text here: it says this memory is running at 1.5 Ghz ... no idea were this info is coming from). Each processor is running at a clock speed of 80 MHz. With a fully filled system, you got more sample ram (=672 MB) and 28 processors running in parallel doing only digital signal processing. It is like a separate PC, but then with multiple processor cores only doing signal processing. The processors are of the type Motorola DSP56309 24-bit digital signal processors. Although the clock speeds is not so high compared to our modern computers, one has to realize these processors where developed especially for doing signal processing. With much less instructions, or clock steps, the same is performed. Therefore, with 28 processors running in parallel this system often has more processing power available then any conventional computer.



There is not an operating system (like Windows) running on the Capybara-320; control is done using a normal laptop, desktop-pc or Mac. On the control side Kyma (user interface)-software is running. With the Kyma software, you can program the Capybara-320. Sound is outputted from the Capybara-320 via a balanced output. Up to eight in and outs are available: analog or digital. A basic system is configured with four ins and outs. The Kyma software is running on the desktop-pc that is connected to the Capybara-320 via fire wire (Christiaan is still using the old-fashioned pci-i/o card). Via Midi, one can control or influence the process (there are also exiting controllers available: like a Wacom Intuos3 4x5 USB Tablet, Continuum fingerboard (see ) or maybe you prefer a Nintento Wii interface via OSCulator (see )). To conclude, one can use the Capybara-320 as synthesizer, sound processor, or both. The fun thing is you can make whatever you like: Oscillators, FM or PD Oscilators, Bitcrushers, Vocoders, Filters etc etc anything you need.


Advanced Mathematics

To get more acquainted with this system and to hear what can be done with Kyma, we visited a Kyma-user: Christiaan Gelauff. Christiaan is one of a few which can make its one microsounds (read: plug-ins) for Kyma. These plug-ins consists of 3 major parts: Assembler code for the Capybara-320, CapyTalk for the control parameters within Kyma and a companion Wrapper Sound Class (read: simple user interface). Christiaan is developing synthesis and audio processing algorithms. Filters are his specialty.


Christiaan: " I am more a guy of the simple analog synth: a sawtooth and a filter, you know… and that was the exactly the one and only thing that was not possible with this device."

IF: "That is strange… not?"

Christiaan: " Well, it was possible - there are off coarse filters and oscillators in Kyma - but to my opinion they did not sounded good enough, especially in the earlier releases of Kyma. Therefore, I had a goal to rewrite those. I searched for filters with some different sound, maybe more analog like (what ever that may be).


Christiaan loads a few files in Kyma and explains how he created the filters and what the problems are in designing the filters. Mainly it is about advanced mathematics...

Then he plays the result and I am astonished about the beautiful sound of these filters he has created.


IF: "That Vowel filter I hear: great!"

Christiaan: "That are two band pass filters, oops sorry: three band pass filters. And another one, but in fact it is doing nothing, because I did have any useful information for it. Most of the time the vowel sound-lists only indicates three frequency bands. And yes, bandwidth of the filters: try something, just by tweaking...then putting the vowels on controllers. I did this in a sort of two-dimensional way, like in vector-synthesis. I first tried to do it in a 3 dimensional way with 8 points, like one can find in Z-plane filters of EMU. It did not turn out to work that great, so that is why I put it on to two controllers only. The controllers modulate the center frequencies in such a manor one can move from one vowel to the other."

IF: "What can we do with this?"

Christiaan: "If you own a Capybara-320 system, my filters can be used in your own Kyma projects. This system is used by different users ranging from sound designers to performance artists".


Staggering filters and oscillators

With a dizzy head full of information, I say good-bye to Christiaan. I am deeply impressed by the stuff he designs on this system, but at the same time I feel it is a pity his stuff is only available for such a small amount of users. Maybe you should judge for yourself via his website. The filters and oscillators Christiaan created should be available in a hardware box or in a VST-plug-in. They are for sure worthwhile. Or should we all go for the Capybara...


Page was updated on: Wednesday, December 05, 2007