Fantasy Birds in Yazi's Dream
Lydia Ayers
Tower 14, Flat 7A, HKUST
Clear Water Bay, Kowloon, Hong Kong
email: layers@cs.ust.hk
Abstract
Yazi's Dream celebrates the life of Yazi, our first cat.
This project uses the dizi, a Chinese transverse flute
that often imitates bird songs, to make tremolos for the
fantasy birds used in Yazi's Dream.
1 Introduction: Yazi's Dream:
Yazi's Dream
celebrates the life of
our cat. The recorded
birds represent the birds
Yazi watched and tried
to talk to through the
window. Synthesized
- tremolos on the dizi, a
Figure 1. Yazi and Dizi Chinese bamboo
membrane flute (see
Figure 1), represent Yazi's bird fantasies. Yazi's
panting breath becomes the wind whistling in the
shadows of a mountaintop. Muyu, buddha gongs and
qing (see Figure 2) play a parade of memories honoring
her life.
slide a tremolo across a large interval. Joining dizi
sliding tremolos to other notes produces bird melody
fragments. Figure 5 shows a dialog among the cat,
the real birds and the dizi sliding tremolos and pitch
bend representing the fantasy birds. The dialog
among the cat, the birds and the dizi returns at the
end of the piece, when the cat sound is stretched,
lowered and granulated.
Figure 3. Additive Synthesis Design
-A
Figure 2. Muyu, Buddha Gong and Qing
(Clockwise from Left)
2 The Additive Synthesis Instrument:
Inspired by the bird songs that dizi performers often
imitate, the new additive synthesis design uses up to 30
harmonics (see Figure 3), each with slight random
inharmonicity, vibrato, amplitude interpolation, slow
and fast amplitude noise, and a very small amount of
filtered breath noise (Ayers 2005). The large random
variation in the spectral amplitudes better simulates the
instability of the dizi timbre, and makes the tones sound
more lifelike than wavetable synthesis does (see Figure
4). Frequency and amplitude modulation for each of
the harmonics of a single signal make dizi tremolos for
Yazi's fantasy birds.
3 Fitting the Model into the Piece:
In the 'Looking at Birds' section of Yazi's Dream, dizi
fantasy birds dialog with recorded bird sounds. Once
we completed the dizi tremolo model, it was quite
interesting to vary it to produce effects more like birds
than dizi sounds. For example, it is possible to slide
from one dizi pitch to another by moving the fingers
slowly across the open holes, but it is not possible to
Figure 4. Synthesized Dizi Tone
Figure 5. Dialog Among Cat, Real Birds
and Fantasy Birds with Dizi Sliding
Tremolos in Yazi's Dream
References:
Ayers, L. 2004 (remixed). Yazi's Dream.
Ayers, L. 2005. "Synthesizing Chinese Flutes Using
Csound," Organized Sound, 10(1).
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