the sounds of music
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The Sounds of Music. The Musical Sound Sound concepts parameters: duration amplitude frequency harmonics phase direction Analog representations Digital representations ADC-DAC sampling quantization format. The Sounded Music music as performance live vs. recorded expression - PowerPoint PPT PresentationTRANSCRIPT
The Sounds of Music
The Sounds of Music
• The Musical Sound– Sound concepts
• parameters:– duration– amplitude– frequency– harmonics– phase– direction
– Analog representations– Digital representations
• ADC-DAC• sampling• quantization• format
• The Sounded Music– music as performance
• live vs. recorded• expression
– tempo– dynamics– vibrato– timbre
• Instruments and Technique
• The Sight of Music– the performer– the environment
Olivier Messiaen
(1908–92)Quatre études d
e rythme, 1949–502: Mode de valeu
rs et d'intensités, 1949
Pierre Boulez (1925–
)Structures, bo
ok 1, for 2 pianos, 1951–2
premiered by Messiaen & Boulez in, Paris, 1952
The Musical Sound
• Hearing: changes in pressure
frequency=~20Hz–20kHz[Heinrich Hertz 1857–
94 (telegraph)]
intensity ratio=~20–100dB[Alexander Graham Bell,
1847–1922 (telephone)]
ffffffffff
mfmp
ppp
ppppppp
Sound Concepts
• A=amplitude – max. elongation
• λ=wavelength– distance between two points of the same ph
ase• f=frequency=1/λ
– cycles per second (Hz)
overtones-harmonics-partials
tone
sound
noise
Phase
• phase shifted by 180º– phase distortion,
audio image out of focus
Analog
• air pressure analogous to electrical voltage
• continuous-time signals
• problem: mechanical noise, multiplies in copying
Digital
• air pressure-electrical voltage-binary digits (bit)
• discrete-time signals
• ADC• DAC
Analog
Digital encoding
Analog decoding
Binary vs. Decimal
base two (0–1) base ten (0–9)
1001 9
1010 10
1011 11
1100 12
1101 13
1110 14
1111 1516 bit
Sampling
• distortion caused by too low a sampling rate– original– reconstructe
d
Foldoversampling:
8x 2x <2xreconstruction:
good min. highlow (lowpass filter!)
Quantization
• 1-bit vs. 4-bit – 1-bit=2 amplitude
levels– 4-bit=16 amplitude
levels
Quantization
• 4-bit vs. 8-bit• the higher the b
it-rate, the greater the dynamic range (from loud to soft)
• 1-bit=6 bB, 16-bit=96 dB
Quantization and Sampling Rates
• CD: 16 bit/44.1 kHz/stereo, 12 cm Disc: 650–700 MB– Red Book standard 1980
• DVD: 24 bit/96 kHz, 4.7 GB– 1998
• SACD: 2.8 MHz, 4.7 GB– 1999
MD, mp3, DAT…
– compressed format, not recommended for research• MD• mp3
– DAT: good but magnetic…
Graphical Representations of Sound
2-D
3-D
• temporal representation– amplitude vs. time
• spectral representation– amplitude vs. frequency
– frequency/intensity vs. time (spectrogram)
Flute
Singing
Speaking Voice
Bird
Bat
Timbre as Expression
• bel canto vs. pop• musician vs. singer• traditional vs. authentic • counterpoint vs. Klangmotiv
Sound of Music
• “sol do la fa mi do re, sol do la ti do re do”“But it doesn’t mean anything!”“So we put in words, one word for every note, like this…” (Sound of Music)
• “Thus, music no longer in need of words now seems more than ever in need of words.” (Scott Burnham)– 侯珅譯 : 現在不需要文字的音樂似乎比有文字的音
樂還要多 )!?• “A picture is worth a thousand words.”
Literature• Clarke, Eric F., and Nicholas Cook, eds. Empirical Musicol
ogy: Aims, Methods, Prospects. Oxford; New York: Oxford University Press, 2004.
• Parncutt, Richard, and Gary McPherson, eds. The Science & Psychology of Music Performance: Creative Strategies for Teaching and Learning. Oxford; New York: Oxford University Press, 2002.
• Rink, John, ed. Musical Performance: A Guide to Understanding. Cambridge; New York: Cambridge University Press, 2002.
• Day, Timothy. A Century of Recorded Music: Listening to Musical History. New Haven: Yale University Press, 2000.
• Rink, John, ed. The Practice of Performance: Studies in Musical Interpretation. Cambridge; New York: Cambridge University Press, 1995.