Post on 10-Feb-2018
7/22/2019 FY Seminar Acoustics
1/55
First Year Seminars:Music and the Mind
&
Music Mediated
The Acoustics of Music
7/22/2019 FY Seminar Acoustics
2/55
Music AcousticsI suspect that many people share the
romantic sense that music is a product ofnuminous inspiration, and are apt to feeldisheartened, even appalled, when it isfragmented and seemingly reduced to a matter of
mere acoustics, of the physics and biology ofsound and audition. I don t intend to apologize for a digressioninto the mathematics, physics and physiology of
acoustic science by justifying it as an unavoidableintroduction to the raw materials of music.It is much more interesting than that.
~ Philip Ball
7/22/2019 FY Seminar Acoustics
3/55
What is SOUND?
7/22/2019 FY Seminar Acoustics
4/55
Sound
If a tree were to fall on anuninhabited island,and no one were around to hearit,
would it make a sound?
7/22/2019 FY Seminar Acoustics
5/55
Sound: Definitions
A DISTURBANCE OF AIRMOLECULES THAT IMPINGES UPONTHE EARDRUM .
Scientific def: Sound = Compressionand rearefaction within a medium.
What
s a medium?
7/22/2019 FY Seminar Acoustics
6/55
Sound WavesSound travels as a wave.Sound Waves can: carry a little energy or a lot. be short or long. travel fast or slow.
All waves (Sound, light, X-ray), share basiccharacteristics:
1. amplitude2. wavelength3. frequency
7/22/2019 FY Seminar Acoustics
7/55
7/22/2019 FY Seminar Acoustics
8/55
Sound travels as a wave:Compression
Decompression, expansion orrarefaction
7/22/2019 FY Seminar Acoustics
9/55
Sound WavesBasic characteristics: Amplitude: The higher the wave moves
up-and-down as it vibrates,
the larger the amplitude of the resultingwaves.
7/22/2019 FY Seminar Acoustics
10/55
Sound WavesBasic characteristics: Wavelength: Def.: The distance
between two consecutive crests ortroughs of a wave.
The wavelength can be measured frompoint to point.
7/22/2019 FY Seminar Acoustics
11/55
Sound Waves Wavelength:
short wavelengths = High Frequencies
long wavelengths = Low Frequencies
7/22/2019 FY Seminar Acoustics
12/55
Sound WavesBasic characteristics: Frequency: Def.: Number of complete waves,
or complete cycles, per unit of time. Frequency is measured in hertz (Hz). Hz = # of Vibrations per second.
7/22/2019 FY Seminar Acoustics
13/55
Sound waves: musical
? Music = what kind of sound waves? ? Noise = what kind of sound waves?
The factor that makes the differencebetween
music
and
noise
is called: _______________ ?
7/22/2019 FY Seminar Acoustics
14/55
Sound waves: musical
? Music = what kind of sound waves? Regular/Repeating
? Noise = what kind of sound waves?Irregular
The factor that makes the differencebetween
music
and
noise
is called: periodicity
7/22/2019 FY Seminar Acoustics
15/55
Sound waves: musical
Periodic i ty is the factor whichmakes the difference between
~ one ~vs
Noise
7/22/2019 FY Seminar Acoustics
16/55
Sound waves: musical
High Pitch/short wavelength: travel in STRAIGHT LINES will hit an obstacle ( e.g. wall ) and be reflected in another
direction (bounce back); reflect ion (physics)
7/22/2019 FY Seminar Acoustics
17/55
Sound waves: musical
Low pitch/long wavelength: will BEND when hitting an obstacle
and keep going; refract ion
7/22/2019 FY Seminar Acoustics
18/55
4 Properties of Musical TONE Scientific Term Definition Objective Term
Frequency # of cycles persecond,measured inHertz (Hz)
Pitch
Amplitude Intensity Loudness
SpectralEnvelope
Timbre Quality; Tonecolor
Duration Length Time
7/22/2019 FY Seminar Acoustics
19/55
Spectral Envelope/Timbre
Musical Sound, a.k.a
tone
: Complexper iodic v ibra tions
The lowest, slowest and strongest frequency:
Fundamental: F 0
Frequencies over F 0: Overtones, Harmonics* *preferred term
7/22/2019 FY Seminar Acoustics
20/55
Harmonics
7/22/2019 FY Seminar Acoustics
21/55
Harmonics
Harmonics : Frequencies which occur at wholenumber multiples* of the Fundamental (F 0); ex.: x1, x2, x3, etc.term: Consonance(con = with ; - sonance = sonar/sound) Partials: frequencies which occur above F 0 butNOT at Whole number multiples* of the F 0.term: DissonanceDis- against; - sonance = sonar/sound
7/22/2019 FY Seminar Acoustics
22/55
Overtones: 2 types
Harmonics Whole numbermultiples of the F 0
Part ialsNot Whole numbermultiples of the F 0 Interfere withsound, createroughness Noise
7/22/2019 FY Seminar Acoustics
23/55
Harmonics
Harmonics are what give anymusical instrument its particulart imbre.
Timbre is an identifier: a
sonicfingerprint,
unique to each instrument.
7/22/2019 FY Seminar Acoustics
24/55
Harmonics
Every musical intrument has someharmonics which are: Emphasized- boosted -
louder
and Reduced attenuated -
softer
This sonic
fingerprint
is called: spec t ra lenvelope
7/22/2019 FY Seminar Acoustics
25/55
Clarinet A 440
7/22/2019 FY Seminar Acoustics
26/55
Flute G 4
7/22/2019 FY Seminar Acoustics
27/55
7/22/2019 FY Seminar Acoustics
28/55
Human Voice (Singing)
7/22/2019 FY Seminar Acoustics
29/55
7/22/2019 FY Seminar Acoustics
30/55
Harmonics
Harmonics are: Frequencies whichoccur at whole number multiples* ofthe F 0; ex.: x1, x2, x3, etc.This series of Frequencies is called theHarmonic Series.
Example: Low C = 130 Hz, where (atwhat frequency) should the harmonicsoccur?
7/22/2019 FY Seminar Acoustics
31/55
Harmonic SeriesC 3 = 130 (F 0 and H 1 are the same)2nd H = C 4 = Hz?3rd H = G 4 = Hz? 4th H = C 5 (
middle C
) = Hz?5th H = E 5 = Hz?
7/22/2019 FY Seminar Acoustics
32/55
Harmonic SeriesC3 = 130 (F 0 and H 1 are the same)2nd H = C 4 = 261 Hz 3rd H = G 4 = 392 Hz 4th H = C 5 (
middle C
) = 523 Hz5th H = E
5= 659 Hz and so on
7/22/2019 FY Seminar Acoustics
33/55
Harmonics: 2 types
Harmonics Whole numbermultiples of the F 0
Part ialsNot Whole numbermultiples of the F 0;
Other
Interfere withsound, createroughness Noise
7/22/2019 FY Seminar Acoustics
34/55
Harmonics:
Take-Home MessageThe more HARMONICS in the tone, the more:
Musical, pleasing, in
tune IT SEEMS.The more partials in the tone, the more noisy, alarming(exciting!), out-of-tune it SEEMS.
7/22/2019 FY Seminar Acoustics
35/55
Terms
ConsonanceDissonance
7/22/2019 FY Seminar Acoustics
36/55
Equal Temperament
The tuning system used in modern,Western music, in a 12 tone scale:
Based on pure, mathematical ratios ofonly the octave and 5th intervalsbut not for the other intervals (2nd, 3rd,
4th, 6h and 7th)
7/22/2019 FY Seminar Acoustics
37/55
Harmonics
The Amplitude of Harmonics often (notalways) diminish in frequency (Hz) as theygo higher
??: What does this mean re:
loudness
of harmonics?
7/22/2019 FY Seminar Acoustics
38/55
The Ampli tude of Harmonics diminishin frequency (Hz) as they go higher
7/22/2019 FY Seminar Acoustics
39/55
Coupled Acoustics
1. Musical Instruments/3 Elements in Common
2. Actuator3. Vibrator 4. Resonater
7/22/2019 FY Seminar Acoustics
40/55
3 Elements: VOICE
1. Actuator: AIR
2. Vibrator: VOCAL FOLDS3. Resonater: LARYNX, PHARYNX ,
AND ORAL CAVITYLaryngeal, pharyngeal, oral (or
buccal
)
7/22/2019 FY Seminar Acoustics
41/55
3 Elements : Violin
1. Actuator: bow
2. Vibrator: string3. Resonater: body
7/22/2019 FY Seminar Acoustics
42/55
3 Elements : Piano
1. Actuator: hammer (finger)
2. Vibrator: string3. Resonater: body
7/22/2019 FY Seminar Acoustics
43/55
3 Elements : Clarinet
1. Actuator: air (lips)
2. Vibrator: reed3. Resonater: body
7/22/2019 FY Seminar Acoustics
44/55
3 Elements : Trombone
1. Actuator: lips
2. Vibrator: lips3. Resonater: body
7/22/2019 FY Seminar Acoustics
45/55
Resonance: Definitions
The amplification, reinforcement, or prolongation of vibration when anothervibration of the same frequency isapplied to it. Text: page 72)Merriam-Webster Dictionary:
theintensification and enriching of amusical tone by supplementary
vibration
(see also Glossary in Text)
7/22/2019 FY Seminar Acoustics
46/55
Resonance: 2 Types
1. Forced (ak.a. conductive ) Depends upon direct, mechanical connection ofactuator to vibrator
2. Free (a.k.a. sympathetic)Depends upon reflections of soundwaves within avoid3 conditions:
1. Structure must be hollow2. Have enough space3. Have an opening for exit of soundwaves
7/22/2019 FY Seminar Acoustics
47/55
7/22/2019 FY Seminar Acoustics
48/55
Resonance Clarification: 3 main resonators:
1. Pharynx
2. Larynx
3. Oralcavity
(not
mouth
)
7/22/2019 FY Seminar Acoustics
49/55
Resonance: factors
3 factors affect resonance:1. Size2. Shape3. Texture
These factors affect all 4 properties of musicaltone* (Some more than others).
(REVIEW: WHAT ARE THE 4 PROPERTIESOF A MUSICAL TONE?)
7/22/2019 FY Seminar Acoustics
50/55
4 Properties of Musical TONEScientific Term Definition Objective Term
Frequency # of cycles persecond,measured inHertz (Hz)
Pitch
Amplitude Intensity Loudness
SpectralEnvelope
Timbre Quality; Tonecolor
Duration Length Time
7/22/2019 FY Seminar Acoustics
51/55
Resonance: 3 factors1. Size
Affects Frequency & timbre; how/why?Voice: How might this relate to gender?
7/22/2019 FY Seminar Acoustics
52/55
Shape
Affects Frequency &timbre how/why?
7/22/2019 FY Seminar Acoustics
53/55
Affects on Resonance of:Texture?
7/22/2019 FY Seminar Acoustics
54/55
Venues
7/22/2019 FY Seminar Acoustics
55/55
Pavarobotti