I am a final year student on the Electronics with Music B.Eng. degree at Glasgow University and began using CSound this year as part of our Software Synthesis and Composition Systems (SS&CS) course. Having worked previously with hardware synthesizers, I found that CSound offered a much more flexible approach to sound synthesis. The diversity of synthesis techniques which can be employed allows the realization of sounds which could not be created with most hardware synthesizers. The additional sound mixing and sound processing capabilities also make CSound attractive as so much can be achieved without the use of additional software and external effects processing units.
I have studied classical and contemporary drums and percussion since the age of 8 and have been performing in public since age 9. I currently play regularly around Scotland with a number of different jazz groups, including performances at the Glasgow International Jazz Festival, Dunoon Jazz Festival, and a recent tour promoted by Assembly direct. I have played live on national radio on several occasions and recently appeared in STV's "High Road" as a body percussionist. I have also composed numerous small band jazz pieces, two pieces for jazz big band, and an arrangement for saxophone quartet.
I was a Scottish Finalist in the Louis Award for Young Jazz Musician of the Year in both 1996 and 1997. In 1996 I was awarded a partial scholarship to Berklee College of Music, MA, USA. In 1994 I won the Daily Telegraph Young Jazz Award for composition and was a runner up in the soloist category. I recently received the Farnell prize for the best final year electronics hardware project for the design of a wireless MIDI interface, under the supervision of Dr Miranda and Dr Muir.
In this composition I brought together a number of different synthesis techniques which I have been experimenting with over the last year in our course; Amplitude Modulation, Frequency Modulation, Subtractive Synthesis, Waveguides, and Granular Synthesis techniques were used. I was interested in creating sounds which were reflective of the real world in some way but which also had an unnatural quality. Some of these sounds were created by developing a CSound instrument which imitated a real instrument and then modifying it in such a way such that the resulting sound was quite different from that originally intended.
The piece is 60 seconds long and is comprised of six 10 second sections. Each sound event was created separately in mono and then all sounds were mixed and panned in the stereo field using the CSound soundin unit.
The piece begins with a whining drill-like sound in the left stereo channel. Although now unrecognizable as such, this sound began its life as a human voice instrument created using Subtractive Synthesis to model the human vocal tract. The length and shape of a real vocal tract are varied to create different resonances in the frequency spectrum of the voice and thus form different vowel sounds. This instrument uses filters with different resonant frequencies to model the resonances of the vocal tract. The instrument is capable of producing the vowel sounds "a", "E", "I", "O", "u" and the words "wa", "we", "ow" using a combination of these vowels. The vowel is selected using a single pfield in the score file which can have value from 0 to 7.
I created this particular sound by having a high "I" (note value 10.08) and a low "wa" (note value 6.07) play simultaneously. I then increased the vibrato rate to 100Hz, which actually created amplitude modulation, and applied an envelope to the fundamental frequency so that it drops off towards the end of the sound. The resulting sound is like that of a drill, spinning very fast and then being turned off and slowing down suddenly.
The second section uses two instruments. The first is a simple Amplitude Modulation bell instrument with one carrier and one modulator. The second is a combined Amplitude/Frequency Modulation instrument with a time varying frequency modulation index. The carrier frequency is therefore both frequency and amplitude modulated. By using different parameter values I was able to create some interesting buzzing and bubbling sounds, which give the impression of flying electronic insects. Separate score files for the left and right stereo channels were used.
Section 3 uses a very similar AM/FM instrument to that of the previous section. However, in this case the score files were generated using a random score generator to create a granular synthesis effect. Where previously, long notes were used, here all notes have a very short duration. Three different score generators (programmed by myself in C) were used. In each case the duration, amplitude, fundamental frequency, modulation frequency, FM modulation index, and AM modulation index were randomly generated. However, for each case the range of these parameters was different, as was the tempo and number of events used. The resulting sound is like that of insects scurrying and wriggling around.
The random score generators used were "beasts1.c", "beasts2.c" and "beasts3.c". The ".c" file must be compiled and then used to create the score file. When the ".c" program is run, it asks for "number of events: ". The user then types the number of events required and hits RETURN. This generates the score file which can then be used in the standard way. Three example score files, "beasts1.sco", "beasts2.sco" and "beasts3.sco" are included and all of these use the same "beasts.orc" orchestra file.
In section 4 a variety of sounds were used. There is a burst of white noise in the right channel (just a simple random generator: "asig rand iwhite") and the insect sound of section 2 returns briefly. Then there is a sequence of vowels, produced using the human voice instrument described earlier. However this time, no amplitude modulation was used and there was no envelope applied to the fundamental frequency. A random score generator was used to generate the score file. The frequency, duration and vowel sound were randomly generated. Once the sound file was created, the entire sequence of vocal sounds was processed using a resonant filter (reson) with swept centre frequency. This is another example of a fairly natural sound which was processed to produce something almost unidentifiable. The random score generator used was "randvce.c" which operates similarly to "beasties.c".
In the left channel a flute instrument was used. This was created using Waveguide synthesis and was based on Perry Cook's slide-flute program for the NeXT computer. The Csound files for this are not included, here. Two notes were used, one very high and the other very low. The result is therefore quite unlike that of a real flute.
After the flute-like sound, the drill sound of section 1 returns. This time it stays at the lowest frequency once it has been reached and gradually crescendos until the end of the piece.
Sections 5 and 6 In the last two sections various sounds from the earlier sections return almost like a recapitulation.