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CHAN Joshua Kam-biu / 陳錦標


Unknown journey / 未知旅程
[wei zhi lü cheng]

Birth Y: 1962 Birth C: HONG KONG Gender: Male

Dest: Concert

Media Specification: Tape (stereo)

First perf.: University of Hong Kong, Hong Kong, 13 April 1992.

Duration: 9:45

Perf. Country: HONG KONG

Instruments: Stereophonic tape

Perf media: Software: Turbosynth. Sampler: Emulator III. Synthesizer: Roland WaveStation, Yamaha TX81Z. MIDI.

Publisher: Unpublished. Reproduced from Hong Kong Music Collection's donated score, 1991, c2002, Hong Kong Central Library, 002240949, PVCHA MC1956.

Media: CD

Prog. notes: The first step in the production of Unknown Journey was the creation of original voices (sound units). Several approaches were used:
1) The software Turbosynth was used to create waveform sequences constructed with Fourier synthesis techniques.
In working with Fourier synthesis, one creates a harmonic spectrum by determining the combination of amplitude levels of various harmonics. In other words, the user is free to select which harmonic, how many harmonics, and how big the amplitude is to be for each selected harmonic (Turbosynth uses a range of harmonics from partials 1 to 64). With the aid of the computer, the result of this harmonic combination is calculated and presented as a graphic waveform whose sound can be heard through the internal speaker of the computer. These waveforms can be played as a long sustained tone or as short slices of sound lasting for tenths of a second.
After creating a library of these waveforms, my next step was to connect different waveforms into a meaningful sequence so as to create a more realistic sound. The result of this waveform 'composition' was then subjected to various kinds of digital and analogue enhancements such as applying an amplitude envelope and/or pitch envelope, modifying its pitch, adding pitch-detune chorusing effect, compressing or stretching its production time, and so on. This process is often called modular synthesis: new sounds are created by designing a particular routing through various modules for a given sound to go for various sound treatments.
2) The software Turbosynth was again used, this time to enhance and modify samples of my voice and other sounds.
The most striking aspect of this facility is that one can re-order, duplicate, reserve, magnify, diminish, etc any segments of the original sample (short or long) and turn it into something totally unrecognizable, especially when segments of different originals are combined. The manipulation of these segments, similar to the waveform combination mentioned above, is a very creative process, not unlike the act of composition, with one's personality, artistic conception, and cultural influences all contributing. With Turbosynth , the product of this manipulation can also subjected to modular synthesis of any kind.
Voices created using this approach (sample modification) and the previous one (Fourier synthesis with waveform sequencing and modular synthesis) were sent to the Emulator III sampler as new samples, and stored as Emulator III voices.
3) The third approach was to create waveform-sequencing sounds by programming the Roland WaveStation synthesizer.
Inside the WaveStation, we have 365 waves to work with. Each wave has a unique timbre. Waves can in fact either be single-cycle or few-cycle waveforms that loop continuously; sampled transients followed by loops; or sampled transients which play only once.
4) Another group of voices was created using FM synthesis techniques. These voices, generated by the Yamaha TX81Z synthesizer, tended to produce metallic sounds because of the use of inharmonic spectra and of modulations where one frequency generator (operator) affected another.

The second step of the production was to programme the effect unit QuadraVerb, a multi-effect system which allows the user to decide on the amount and routing of the audio signal which goes through various effect modules (within QuadraVerb). These effects include:
1. Reverberation
2. Delay (mono delay, stereo delay, ping-pong delay)
3. Equlization (increasing or reducing the amplitude of any frequency range of a sound)
4. Pitch modification (enriching the quality of a sound by adding detuned shadow)
The combinations of these effects can be very interesting. For example, the sound of a screaming can be followed by 2 echoes coming back at different time on the left and right channels, respectively. The sound qualities of these echoes can be modified by adding pitch detune, or reducing its high-frequency component. The overall effect can also be spacialized by adding reverberation. Each specific combination of these effects is stored as a programme. QuadraVerb is capable of storing 99 programmes in total. These effect programmes can be triggered at any precise moment by the computer with MIDI commands.

In the production of this piece, the software sequencer Performer was used to control all the sound modules and effects units, sending MIDI commands such as information concerning pitch, volume, starting time, duration, programme change (asking a particular synthesizer or effect unit to change from one voice type or effect programme to another), etc. The great timing precision of this idiom had enabled me to created some complicated rhythmic effects which cannot be created with acoustic means.

The actual stage of composition could not begin until I got most of the voices and effect programmes created. During the composition stage, new voices and effect programmes were constructed when needed, which means I went forward and backward between composition and voice creation. For compositional reasons, adjustments of original voices or effect programmes are always needed. The most typical cases are the delay speed and reverberation decay time: the impact of a delay will vary as the speed of the music changes; sometimes it is necessary to control the delay time so that the appearance of the echo(es) does not disrupt the musical outcome.

In this composition, the actual presentation of musical materials in terms of phrasing and form assembles those found in acoustic music. For example, the introduction consists of three statements of a simple texture of sustained sounds. Each statement is answered/disrupted by a percussive sound which is enlarged at the third statement by ping-pong echoes. Then the music progresses with a new section that has a more subtle phrasing structure. In the overall form of the piece, several technical & artistic elements are essential: gradual transformation of timbre; the use of silence; rhythmic accelerando (which turns macro-rhythm into micro-rhythm); and the texturally complicated human-voice ensemble.

這首樂曲中聲音設計的另一個重點是製造聲波系列﹐使持續發聲的樂音在時間空間中不斷變型﹐形成一系列的音色變化。另一類的音色單元是利用頻率變動合成法在電子合成器 TX81Z 上製造聲音。這種比較金屬化的聲音揉合了不協調泛音和頻率產生器的自我影響法兩者的特徵。

Editor: Ka Lun CHEUNG

Phono: CD1:

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