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.