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76 Cards in this Set
- Front
- Back
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Definition of sound |
VIBRATIONS propagating through MEDIUM in WAVES to which our EARS are SENSITIVE |
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Can medium affect the characteristics of sound? |
Yes, sound cannot be transmitted in a vacuum, usually in air but can be through walls, strings, water. |
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Three variables of sinusiodal waves |
Frequency (f), amplitude (A), phase (ø) |
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Significance of w in x(t) = A sin(wt +ø) |
Angular frequency (rad/s), w = 2pi * f |
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Definition of pure tone |
Single sine wave |
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Definition of complex tone |
Repeating pattern, but not simple sine wave. FUNDAMENTAL FREQUENCY |
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State Fourier's theorem |
Any PERIODIC vibration can be represented as the superpostion of PURE HARMONIC VIBRATIONS (partials), whose FUNDAMENTAL FREQUENCY is given by the repetition rate of the basic periodic vibration |
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What field is the study of auditory streaming part of? |
Auditory scene analysis |
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Types of auditory streaming? |
Direction, harmonics partial, common fate, analysis window |
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Definition of fundamental frequency |
Frequency of the partial with the lowest audible frequency that has harmonic multiples |
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Physical to perceptual conversion: Fundamental frequency Amplitude Amplitude of harmonics partials |
Pitch Loudness Timbre |
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Why is the mapping between physical and perceptual not always perfect? |
example: timbre determined by attack of a note, non-harmonic partials and other factors |
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Fourrier analysis definition |
Calculation of particular sinusoidal COMPONENTS making up a given wave over an ANALYSIS WINDOW, providing a snapshot of SPECTRAL CONTENT over that period of time as a whole, NO evolution over time |
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Describe a discrete Fourier analysis |
Histogram with the x-axis representing the bins of frequencies |
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Definition of Fourier spectrum
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Graphical plot of the intensity of each partial during a SINGLE ANALYSIS WINDOW x: frequency y: magnitude Contains both harmonic and non-harmonic partials |
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Axis of time domains |
x: time y: displacement e.g. Audacity |
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Axis of frequency domains |
x: frequency y: displacement Result of Fourrier analysis, represent overall frequency content during a window of sound |
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Limitations of time domain representations |
Specific FREQUENCIES not apparent Bad indicator of TIMBRE Perceptually similar sounds have different WAVEFORMS |
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Advantages of time domain representation |
More intuitive initially See temporal evolution in a simple way Simple representation of physical reality (although the frequency domain also represents the physical reality) Useful for basic audio editing |
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Advantages of frequency domain representation |
Closer to the information that the BRAIN actually receives from the ears Allows one to see the frequency content of a sound as SEPARATED out components USEFUL for signal analysis, signal sculpting and effects processing Gives a representation of a sound over a SET PERIOD of time |
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Axis of spectrograms |
x: time y: frequency color: amplitude of frequency Each column = single analysis window |
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Similarities between Fourier analyses and spectrogram |
Spectrogram is a set of Fourier analyses visually rotated 90 degrees and stacked horizontally |
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Harmonic sounds definition |
Emphasize partials that are multiples of the fundamental frequency |
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Noise definition |
Lack PRECISE PITCH psychoacoustically and frequency spectrum doesn't EMPHASIZE HARMONIC partials |
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Wide-band definition |
Noise containing different frequencies spanning a wide range of frequencies and no sense of pitch at all |
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White noise definition |
Sound containing all audible frequencies |
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Narrow-band definition |
Loose sense of pitch in a diffuse/imprecise sense, frequencies spread over a narrower range of bandwidth e.g. bass drums and cymbals |
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Source-filter model definition |
Models sound based on a combination of noisy sound source and filtering mechanism that modifies the frequency spectrum of the source signal (physical EQ adjuster, gives the sound its characteristic timbre and pitch)
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Example of source-filter model |
CELLO Source: bowing generates noisy sound Filter: strings and cello body filter this scratchy sound HUMAN VOICE Source: vocal chords vibrate to generate a noisy sound Filter: vocal tract emphansizes certain frequency regions (formants) |
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Description of separation of source-filter model |
Stochastic component: noisy part Deterministic part: harmonic part Useful for sound synthesis |
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Parts of human auditory system |
Ears: Outer, middle, inner ear Central auditory system: Brain processes information provided to it by our ears |
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Description of outer ear |
Pinnae: determine direction of sound by filtering frequency spectrum depending on direction, focus sound over large areas into ears Enters ear/auditory canal, amplifying sounds in the frequency range of 3 to 12 Hz |
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Description of middle ear |
Eardrum/tympanic membrane: air coming from auditory canal vibrate eardum Ossicles (hammer, anvil, stirrup): transmit vibrations to OVAL WINDOW of inner ear (amplify 20x, acoustic reflex tightens/loosens to protect ear damage) Eustachian tube: connect middle ear to nasal cavity, allows same pressure in middle ear as atmospheric |
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Description of the inner ear |
Cochlea: convert vibrations to electrical signals via auditory nerve Basiliar membrane: inside cochlea, vibrate due to oval window, rubs agains hair cells (Organ of Corti) [Fourier analysis + time domain] Vestibular system: balance, focus eyes while head move, based on movement of fluid in SEMICIRCULAR CANALS |
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Central auditory system description |
Pre-processes sound to extract descriptive information to interpret sound Brain sends instruction to cochlea to refine sensitivity/frequency selectivity by causing outer hair cells to release chemicals interacting with inner hair cells |
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Primary auditory cortex description |
Brodmann areas 41 and 42, however music processed by many parts of brain |
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Sensations associated with musical sound |
Pitch: sonic height Loudness: strength/intensity Timbre: sonic color Directionality: where sound is coming from |
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Examples of oversimplification of preceptual mappings |
Pitch can be heard without corresponding fundamental frequency (illusion of MISSING FUNDAMENTAL) Sensation of loudness of a tone will VARY according to change of frequency Spectrums not enough to describe timbres (ATTACK/transients) SPECTRUM of instrument can change yet timbre will still remain recognizable |
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Loudness definition |
Expressed in intensity (Sound Pressure Level in air) or power (sound energy/second by source) Based on windows as long as 600-1000ms, not peak amplitude Root Mean Square: averaged out representation of amplitude |
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Examples of 30, 50, 70 and 120 decibels |
30dB: soft whisper 50dB: average background sound in a home 70dB: freight train 120dB: jet takeoff |
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Other units of loudness |
Sones, phons; more perceptually based |
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Amplitude envelope definition |
Shows overall amplitude of sound changes over time |
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Parts of sound (amplitude envelope)
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Attack: start of sound, chaotic transients (timbre perception) Sustain: stable part, source still producing energy; pitch and timbre perception Decay: amplitude drops to zero as energy stops; environment charac. perception (reverb) |
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Neurological reconstruction |
Sensory mind reasing fMRI |
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Commercial functions of music |
Influence people to BUY: - ASSOCIATING mood/feeling or musicians with product - JINGLES; subconscious association with product - Product placement in LYRICS Profit in music made INDIRECTLY now (concert ticket, merchandising, alternative media, ads, licensing) |
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Entertainment functions of music |
Cause pleasure, prevent boredom Beleived to be most important function of music by Westerners, but naive Function usually found in cultures with surplus of resources; prevent boredom and distract from social/personal problems Sound recording and amplification technology makes entertainment economically viable |
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Participatory music functions |
Everyone takes part in performance, no passive Part of everyday life in many cultures Dancing often inseparable Reinforcing social bonds, sense of community (act in the interest of others) e.g. Celtic ceilidhs, musical family gatherings, rap circles |
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Music in the reinforcement of group identity |
Reinforcy GROUP UNITY through making and experiencing music, learn to cooperate Reason why people still go to CONCERTS Political leaders: national anthem, campaign songs Sub-cultures: emphasizing differences between themselves and society (rap, punk, goth) |
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Functions of music as an artistic achievement |
COMMON goals: personal expression, beauty, originality, pursuit of greatness (not relevant in some cultures) Art itself, or SUPPORTING role (opera/ballet/film) Arts/crafts Asserting PERCEIVED greatness of a culture/social class (pyramids, Versailles), means of claiming SUPERIORITY (European > African); RELATIVE, determined SELF-REFERENTIALLY |
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Arts vs crafts |
Art: seen as exalted Crafts: seen as commonplace To outsiders, art and craft is arbitrary and meaningless Socially stratified: important Socially egalitarian: not |
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Music as an emblem of personal social status |
Personal superiority; complex music; patron/sponsor; operas with fake audience |
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Music as a religious ceremony |
Most commonly function - Group identity (singing) - Memorization - Psychological awe and ecstatic - Focus attention (prayer/meditation) Similar to drugs |
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Music as a way to transmit knowledge, values and culture |
Education of children Moral Enjoyable memorization Add emotions to stories |
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Music as a way to express social rebellion |
Dissatisfaction and desire to change (lyrically or programmatically) Stylish differences Rallying point by sub-cultures/political groups alienated by establishment Censorship, subtle/hidden messages, blowing off steam |
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Relationship between social rebellion and high arts |
Financially dependant, Commercial publish (but changing) Direct protest: sponsors agree or criticism hidden |
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Music as a way to select mates |
Animals Love and sex Show off physical worthiness (voice health/strenght, musical virtuosity, dancing skill) Lyrics demonstrating devotion/sensitivity/intelligence Romantic mood |
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Music, sexuality and advertising |
Easy to sell Music/dance associate sex to product/services Tango: Buenos Aires prostitutes |
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Music as a way to coordinate work |
Syncronization, steady pace, prevent boredom
Call and response pattern Used in field hollers (banning of music in fear of coded messages) |
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Military uses of music |
Coordiate movement, inspire courage, intimidate enemy forces, instil unity and loyalty, dehumanize enemy forces |
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Music as a weapon |
e.g. force Manual Norriega to surrender from Vatican by playing rock 'n' roll, prevent eavesdropping by press with long-range parabolic microphones Long Range Acoustic Device: spatial disorientation 2004 siege of Fallujah: soldiers - strong music; civilians - demeaning music for enemy |
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Mosquito device |
Constant 17kHz tone Lose sensitivity after 20-30 |
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Stun grenades |
Loud sound + bright light 170-180 dB within 5 feet Temporary deafness, ringing in head, lack of balance |
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Music and interrogation |
Acoustic blasting + sensory deprivation, sexual/religious humiliation, sleep deprivation, extreme temperatures, stress postures Barney I Love You |
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Healing and health |
Encourage physical/mental activity Encouragement, brighten one's mood Music therapy |
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Music and manipulation |
Artistic reasons: mood for scene in movie Commercial advertising, political manipulation |
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Manipulation in the news |
615music, create sense of authority/excitement, cutting edge, trust, branding Manipulative moods, propaganda |
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Manipulation in advertising |
Calming effect, increase susceptibility, association with mood, earworm/jingles, product placement, sell-out, political |
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Manipulation of musical taste |
Sex (Miley, Timberlake) Want & idol Sexuality in lyrics, sounds evoking, visual imagery in videos/concerts, physical characteristics of artists, personal impressions of artists during interviews Associations with lifestyle, champion (political/personal rebellion), respect/fear gangsta, virtuosic master of refined tradition |
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Example of manufacture of extra-musical associations |
t.A.T.u., fake lesbians, marketed differently to both straight males and lesbians |
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Manipulation of musical tastes by limiting exposure |
Payola schemes Media concentration Internet: easier access Modern listeners less variety than before 2000s TTKP |
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Example of censorship of music |
Shostakovich's Lady Macbeth of the Mtsensk District |
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Example of music specializing in social rebellion |
Lowkey - Obama Nation |
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Example of occasional musical protesters |
Blue Rodeo - Stealin' All My Dreams |
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Example of subtle protest music |
Haydn - Symphony No. 45 |
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All the social functions of music |
Commercial, entertainment, group identity (participatory), artistic achievement, emblem of personal social status, religious ceremony, transmission of knowledge/values/culture, social rebellion, selection of mates, coordination of work, military, healing/health |
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Manipulation and music list |
Artistic, commercial, political, news, advertising, musical tastes |
