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Sound Basics

Sound Basics. ANTH 576L, Jennifer Cool Week 4 Lecture Fall 2010. Sound Envelope. Time Plot of an Actual Sound. Wavelength, Frequency, Amplitude. Speed of Propagation = Frequency x Wavelength. Sound Spectrum. Most sounds are a complicated mixture of vibrations

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Sound Basics

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  1. Sound Basics ANTH 576L, Jennifer Cool Week 4 Lecture Fall 2010

  2. Sound Envelope Time Plot of an Actual Sound

  3. Wavelength, Frequency, Amplitude Speed of Propagation = Frequency x Wavelength

  4. Sound Spectrum • Most sounds are a complicated mixture of vibrations • A sound spectrum is a representation of a sound in terms of the amount of vibration at each individual frequency, usually presented as a graph of either power or pressure as a function of frequency. The sound spectrum of the flute playing this note has a series of peaks at frequencies of 400 Hz, 800 Hz,1200 Hz, 1600 Hz, 2000 Hz, 2400 Hz, etc., which we can write as: f 2f 3f 4f .. nf where f = 400 Hz is the fundamental frequency of vibration of the air in the flute, and where n is a whole number

  5. Frequencies Sound pressure level in dB Human Hearing Audible range about 20 Hz to 20 kHz

  6. Human Hearing

  7. Equal Loudness Contours

  8. Example of an harmonic spectrum: the sawtooth wave

  9. Perceptual Qualities of Sound • Loudness • Physiological description of the magnitude of an auditory sensation • Pitch • Perceived attribute of sounds, which enables an ordering of sounds on a scale extending from low to high • Fundamental frequency (f0) = corresponding physical (not perceptual) term. Pitch & frequency often (mis)used as synonyms • Timbre (tone color) • "The quality of a sound by which a listener can tell that two sounds of the same loudness and pitch are dissimilar.” (ANSI, 1973) Defined by what it is not. • Some important acoustic parameters of timbre • Brightness (spectral centroid) • Attack time and type • Formant structure • Spectral fluctuation during the playing of the sound • See: http://www.zainea.com/pitchtimbre.htm

  10. Perception is interpretation. Cocktail Party Effect • The ability in perception to select one desired sound from a background of ambient noise. e.g., at a party, where many voices speak simultaneously, we can “focus” our ears on one conversation and “filter out” voices and sounds which are equally strong. • A microphone cannot “filter” noise from signal and, thus, placed at the party, records a babble of sounds. • Ear-brain system: moves us from acoustics to psychoacoustics.

  11. Sound in Documentary

  12. Listening • Richard Leacock’s anecdote about working with Robert Flaherty on Louisiana Story. • “the most difficult discipline” — never stop looking, never stop listening, never stop responding to the world around you.

  13. Sight and Sound “We gestate in Sound, and are born into Sight. Cinema gestated in Sight, and was born into Sound.” — Walter Murch “Film is fifty-one percent sound” — Jean-Luc Godard

  14. Alan Lomax • Alan Lomax (1915 – 2002) was an American folklorist and musicologist. He was one of the great field collectors of folk music of the 20th century, recording thousands of songs in the United States, Great Britain, Ireland, the West Indies, Italy, and Spain.

  15. Free Cinema (late 1950s) • Filmmakers as observers, reject role of promoter (Griersonian style documentary) • New light-weight equipment made intimate observation possible • Intent on both listening and watching, fascination with sound and speech rhythms • Focus on people and places society was inclined to ignore or keep hidden • Films were ambiguous, leaving conclusions to the viewers

  16. Free Cinema Examples • On the Bowery (1956) • Momma Don’t Allow (1956) • O Dreamland (1953)

  17. 1960s • New focus on speech—talking people—had revolutionary impact • It was to these people—including people whom audiences had not counted as part of their world—that viewers reacted

  18. Portable Synchronous Sound • Drew Unit at Time, Inc.; Drew Associates • Robert Drew • Richard Leacock • D.A. Pennebaker • Peter Bogdanovich • Cut the cord between camera, sound recorder, and microphone • Synchronization established through use of “Accutron” watch

  19. Effects of Synchronous Sound • Mobility • Changed role of voice-over narration • “When the field footage began to talk and assumed human dimensions, it raised problems: the commentary was in the way.” (Barnouw, 251) • Changed style of editing • “Real time” asserts itself over “Film time” • Subjects begin to “speak for themselves”

  20. Intersecting Aspects • Technical • Subject is in frame, in focus, and well illuminated • Camera, sound, and editing as crafts that support narrative and aesthetic aspects. • Narrative • Film time is not clock time. It is story time, time is condensed, expanded, elided. • Narrative time is configured. Time governed by plot. • Plot: drawing a “sense of whole” out of a chronology • Characters: agents who both act and suffer • Classic Three act structure: beginning, middle, and end • Aesthetic • Technical craftsmanship does not detract from message. • Form and content work together • Be especially aware and reflexive of the aesthetic to which you appeal.

  21. Poetics of Documentary • “The end of writing is to instruct; the end of poetry is to instruct by pleasing.” — Samuel Johnson The Preface to Shakespeare (1765)

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