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Sound Basics

ANTH 576L, Jennifer CoolWeek 4 Lecture

Fall 2010

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Sound Envelope

Time Plot of an Actual Sound

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Wavelength, Frequency, Amplitude

Speed of Propagation = Frequency x Wavelength

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Sound Spectrum

o Most sounds are a complicated mixture of vibrationso 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.

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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

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Human Hearing

• Frequencies • Sound pressure level in dB

Audible range about 20 Hz to 20 kHz

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Human Hearing

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Equal Loudness Contours

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Example of an harmonic spectrum: the sawtooth wave

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Perceptual Qualities of Sound

o Loudnesso Physiological description of the magnitude of an auditory sensation

o Pitcho Perceived attribute of sounds, which enables an ordering of sounds

on a scale extending from low to higho Fundamental frequency (f0) = corresponding physical (not

perceptual) term. Pitch & frequency often (mis)used as synonymso Timbre (tone color)

o "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.

o Some important acoustic parameters of timbreo Brightness (spectral centroid)o Attack time and typeo Formant structureo Spectral fluctuation during the playing of the soundo See: http://www.zainea.com/pitchtimbre.htm

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Perception is interpretation.

Cocktail Party Effect o 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.

o A microphone cannot “filter” noise from signal and, thus, placed at the party, records a babble of sounds.

o Ear-brain system: moves us from acoustics to psychoacoustics.

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Sound in Documentary

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Listening

o Richard Leacock’s anecdote about working with Robert Flaherty on Louisiana Story.o “the most difficult discipline” — never stop

looking, never stop listening, never stop responding to the world around you.

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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

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Alan Lomax

o 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.

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Free Cinema (late 1950s)

o Filmmakers as observers, reject role of promoter (Griersonian style documentary)

o New light-weight equipment made intimate observation possible

o Intent on both listening and watching, fascination with sound and speech rhythms

o Focus on people and places society was inclined to ignore or keep hidden

o Films were ambiguous, leaving conclusions to the viewers

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Free Cinema Examples

o On the Bowery (1956)o Momma Don’t Allow (1956)o O Dreamland (1953)

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1960s

o New focus on speech—talking people—had revolutionary impact

o It was to these people—including people whom audiences had not counted as part of their world—that viewers reacted

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Portable Synchronous Sound

o Drew Unit at Time, Inc.; Drew Associateso Robert Drewo Richard Leacocko D.A. Pennebakero Peter Bogdanovich

o Cut the cord between camera, sound recorder, and microphoneo Synchronization established through use of

“Accutron” watch

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Effects of Synchronous Sound

o Mobilityo Changed role of voice-over narration

o “When the field footage began to talk and assumed human dimensions, it raised problems: the commentary was in the way.” (Barnouw, 251)

o Changed style of editingo “Real time” asserts itself over “Film time”

o Subjects begin to “speak for themselves”

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Intersecting Aspectso Technical

o Subject is in frame, in focus, and well illuminatedo Camera, sound, and editing as crafts that support narrative and

aesthetic aspects.o Narrative

o Film time is not clock time. It is story time, time is condensed, expanded, elided.

o Narrative time is configured. Time governed by plot.o Plot: drawing a “sense of whole” out of a chronologyo Characters: agents who both act and suffero Classic Three act structure: beginning, middle, and end

o Aesthetico Technical craftsmanship does not detract from message.o Form and content work together o Be especially aware and reflexive of the aesthetic to which you

appeal.

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Poetics of Documentary

o “The end of writing is to instruct; the end of poetry is to instruct by pleasing.”

— Samuel JohnsonThe Preface to Shakespeare (1765)