CA149 First Midterm Lecture Notes
Week 1:
Slide 2:
· John Cage (1912-1992)
o One of the best composers of the 20th century
o Explored other possibilities with sound from musical instruments
o Prepared Piano Sonata V (1946-1948)
§ Prepared piano piece: Put bolts, erasers, all sorts of materials in between/in the strings of a grand piano (opened up piano)
§ Goal: To get new unique sounds from playing the piano
o Active meditator of sound
Slide 3:
· 4’33” : 4 minutes and 33 seconds
o John Cage delayed its release saying it would be a big problem
o The piece: 4 minutes and 33 seconds of silence
§ Organized way to make people listen to the sounds around them during the silence
o Activates different ways of thinking and considering it music
· Pauline Aleveros (spelling could differ): developed idea of deep listening
· Things to consider when listening
o Focusing our brain on what is making sound around us
o Ex. Shirt rubbing, seat moving, noise outside the room, etc
Slide 4: (Slides 5-7 are instruments)
*Instruments used in demonstrations of sound:
· Theremini (Video lecture only)
· Viola (Slide 7)
o Used many ways of playing, such as normally, back of the bow, plucking, etc.
· Bells (Slide 5)
o Sharp sound
o Long decay
· Waterphone (Slide 6)
· How to tell sound apart?
· How do we recognize voices and instruments?
Slide 8: (Bernie Krause video)
· Three basic sources of soundscape:
o Geophony
§ Non-biological sounds that occur in any given habitat
· Ex. Wind in the trees, water waves
o Biophony
§ All the sound generated by organisms in a given habitat at one time and one place
o Anthrophony
§ Sound humans generate
· Some controlled (music, theatre), most noise (chaotic, inherent)
· Careful listening gives us valuable tools to evaluate the health of a habitat across the entire spectrum of life
· Soundscape ecology: recording of sound
o 4 decades ago: 1 hour recording can give enough material for a whole album track
o Nowadays, 1000 hours needed to get the same amount of material
§ Causes of decrease: Global warming, human interference, etc
o Ex. Lincoln Meadow
§ 3 ½ hr drive out from San Francisco
§ 2000 meters altitude
§ Selective logging done
· Before: lots of noise
· After: much more quiet
o Biophony differed lots
o Ex. Mono Lake
§ Home to Great Basin Spadefoot Toad
· Vocalise together in sync
o To mate
o To ward off predators so they can’t tell where each toad is
§ Favored by US navy pilots
· Planes masked the sound of the toads even 6 ½ km away
o Spectrogram: graphic illustration of sound
Slide 9:
· Three categories of soundscape (Bernie Krause)
Slide 10: Sounds while starting your day
o Be aware of how many + what sounds are around you at all times
Slide 11: Sounds as you’re preparing to leave the house
Slide 12:
· How do the items in your space affect the sound you hear?
o ex. Sound bouncing off walls in shower, bed absorbing sound, etc
· How can that change your behaviour?
o trying not to wake someone, etc
Slide 13:
· How does sound change as you leave the house?
o Headphones in? Listening to anything?
· Own sound world?
Slide 14:
· How much of the outside world do you hear when wearing headphones? Concerns?
· What sounds marks signal progress throughout commute?
Slide 15:
· Do you think about your own voice? Changing it?
Slide 16:
· Soundscape (definition): term that covers all the sounds you hear in a space
Slide 17:
· Buckminister Fuller: Defined and stated the quote on slide
Slide 18:
· Quote by R. Murray Schafer
· Canadas most important composer
· Brought up noise pollution, taking in different sounds
Slide 19:
· Quote by Barry Traux
· Cognitive, how brain accepts what we listen to
Slide 20:
· Ways people have classified sounds
Slide 21:
· Classifying sound according to aesthetics
· Can think about beautiful sounds vs Ugly
· Aesthetics is all personal choice
Slide 22:
· Classifying sound according to contexts
o Acoustics
§ What sounds are (Physics, Engineering?)
o Psychoacoustics
§ How sounds are perceived (Psychology, Physiology?)
o Semantics
§ What the sounds mean (linguistics, comms?)
o Aesthetics
§ Do the sounds appeal to an individual (arts; poets, composers?)
·
Slide 23:
· Think about hearing a sound during a time in an event in space, whats important?
Slide 24:
· Causes of sound
Slide 25:
· Ex. Tap shoes
Slide 26:
· Sound will entirely fill any room its in
Slide 27:
· Ambient sound: creek
o Making sound throughout entire length of creek
Slide 28-30:
· Sounds can have
o A distinct source
o No source we can find
o Ambivalent source
§ Unsure of where its coming from, but seems to be coming from there
Slide 31-34:
· Sounds can be
o Extinct
o Endangered
o Imagined (not heard yet)
o Described (using language)
Slide 35:
· List of what sounds can do
o Ex. Shriek, rumble, crash, boom, etc
Slide 36 :
· Onomatopeia
o Sounds used to described sound
Slide 37:
· Cultural specifications for onomatopoeia:
o How different languages have different ways to describe the sound coming from something
§ Ex. Dog barking
· English: bow-wow
· Chinese: Wang-Wang
· Swedish: Voff-Voff
Week 2:
· Sound is movement of air
o Bounces off surfaces, walls, etc
· Sound is the first sense we experience as babies
o In womb, we just hear sounds, not knowing where they’re from
§ Can invoke anxiety when we hear sounds but don’t know where they’re coming from
· “To listen is an effort and just to hear is no merit. A duck hears also.” Igor Stravinsky
· No way to turn ear off
· “What comes together through sound is emergent and passing time – a sense of duration, the field of memory, a fullness of space that lies beyond touch and out of sigh, hidden from vision” D. Troop
· How od sound travel to our brain
o Sound waves in air caught by outer ear (pinna)
o Travels through the ear canal (auditory canal)
o Waves reach eardrum (tympanic membrane)
o Eardrum vibrates, which makes the three bones (malleus, incus, and stapes) vibrate as well
o The bones amplify and send the waves to the cochlea (shaped like a snail)
o Fluid in the cochlea ripple from the vibrations, which creates waves
o Stereocilia (hair like structures) sit on top of hair cells and grouped inside cochlea, rides the waves which moves the hair bundles
o Hair bundle on top of hair cell turns waves into electrical signals
o Ions run into top of hair cells, causing chemicals to release into bottom of hair cells (neurotransmitters)
o Connects to auditory nerves and create a electrical signal which go from ear to brain
§ NOTE: Base of cochlea get higher frequencies of sound, top of spiral detects lower pitched sounds
· NOTE: 1000-3000 Hz : consonants are in this range
o Design of pinna enhances this level
· Ear is incredibly sensitive
o Threshold of hearing: Less than 1 billionth of atmpspheric pressure
§ Amaazing range
o Threshold of pain: 10,000,000,000,000
· Human hearing frequency range: 20 Hz à 20,000 Hz
· The same sounds will sound different at different volumes
· You can hear sounds by touching something that is vibrating
· Sound is mechanical disturbance of a medium (oslid, liquid, gas)
· Sound has physical properties
· Psychoacoustic properties: what we perceive
· Acoustics (classical physics): Study and analysis of sound properties
o Three aspects:
§ Production/Generation: Object vibrates, mechanical energy transferred into acoustic energy
· What makes a sound
· Ex. Speaker
§ Propagation: sound travelling from source to receptor
· Variations in atmospheric pressure which are propagating
§ Perception: Sound is received and interpreted
· Ex. Human ear
· Sound: variations of atmospheric pressure in the sonic (relation to waves and speed of sound) range
· Vibration: back and forth movement of an object
· Sound moves quickest in a solid
· Speed of sound depends on temp of air
· Water: Molecules closer than in gas
· Higher density material à faster speed of sound
Compression:
· Air particles close together
Rarefraction:
· Air molecules far apart
Acoustics:
· Sounds waves: represented in waveforms
o Waveforms help analyze characteristics
§ Wavelength
§ Frequency
§ Amplitude
§ Envelope
§ Harmonics
· Fourier theorem: All waveforms can be thought of as a sum of sine waves
· Hertz: cycle per second
Two halves of sound
· Acoustics: scientific analysis
o Frequency (Hz)
§ Doubling frequency goes up an octave
o Amplitude (dB)
§ How high the middle to top/bottom of a wave is
§ Corresponds to loudness
o Spectrum
· Psychoacoustics: how our brain perceives sound
o Pitch (in octaves)
§ Tied to western music
§ Corresponds to frequency
o Loudness (phone)
o Timbre (recognizable quality)
§ Fletcher Munson curve:
· Sound pressure level vs frequency graphed, produced loudness level phons
Decibel definition:
· Measure of the relative intensity/power level of a signal
· Alexander graham bell
Too loud?
· > 85 dB: only 8 hours per day
Distortion
· Analog ear
o Warmth, non linear
· Digital distortion
o Very bad
o Avoid
Power of 10
· Sound measurement
· Change in dB à exponentially increasing by 10
· Double source itself: ~ +3dB
Sound in time (envelope of sound: variation of intensity of this sound through time)
· Attack
o When you first hit the key
o Key depress
· Decay
o When you first hit the key
· Sustain
o How long you hold the key
· Release
o Let go of key
o Key released
Illusions
· Graphic illusions
o Image illusions
· Aural illusions
o Ex. Girk illusion
§ Perception of something is different between different systems
· Ex. Auditory vs Visually
§ Our senses work together to help us experience our world
o Ex. Phantom words
o Ex. Sheperd tone illusion
§ Overlapping sine tones
§ Sound sounds like it’s going upwards
· Spatial illusions
o Ex. Binuarl recordings
§ Recreation of how our ears hear
§ Stuck mics inside fake made ear canals
§ Recreate sounds going around us
Week 3:
Reverb, echo, spatialization
· Think about hearing instead of vision: compare them
Reverb vs Echo:
· Reverberation:
o Sound reflected so many times that no singular discontinuous repeat of the source is perceived
o Reflective surfaces are too close to listener to allow for subjectivity
· Echo:
o Sound source is distinctly reproduced
o Can be single or multiple
Absorption of sound
· Hard walls vs soft furniture:
o Hard walls reflect sound much clearer, not much absorption
o Soft beds or couches absorb sound, less sound reflected back
· Hard surfaces allow more bouncing, more reflection
o Ex. Large stone churches allow more reverb
· Softer surfaces absorb more sound, less reflection
Time and reverb
· Reverberation time: time it takes for sound to die away to a level 60 dB below its original level
Sound hitting a surface (three things that can happen to sound waves hitting a surface)
· Reflection
o Reflected sound almost as loud as incoming sound
o Hits off surface n another direction
· Absorption
o Absorbing power determined by material used
o Some sound will travel through material instead of bouncing back
· Diffusion
o Scatters sound off surface
Low frequency sound vs high frequency sound travelling
· Low frequency (pitched)
o Really big sound waves
o Moves everywhere, can go around surfaces
o Nothing can really block it
· High frequency
o More directional
o Don’t diffract as much
o Can’t wrap around objects the same way as low frequency
Different types of reverb:
· Chamber reverb
o Put speaker in a very reverberant room (hard surfaced walls)
· Spring reverb
o Put a mic next to springs
o Play sound through spring
o Vibrate spring
· Plate reverb
o Put a mic on plate
o Play sound through plate
· Digital reverb
o Done through technological system
o Done by math
o Control through how sound works
· Convolution reverb
o You make a whoosh, use math to multiply frequency of that sound with any other sound
Parameters (what we can control)
· Roomsize: how soon early reflections of sound will come back to you
· Reverb time: how long does sound actually bounce back and forth
· Damping: how much high frequency sound we lose
· Input bandwidth:
· Dry signal level (dB): works with tail level, how much og sound you hear
· Early reflection level (dB):
· Tail level (dB): works with dry signal level, how much whoosh from air you hear from tail
Week 4:
History of how people thought about sound
· Anything that vibrates causes sound -Plato
· Octave of 7 tones, Orpheus’s lyre given by Apollo, produced harmonies that joined all nature together, Pythagoras playing strings of different lengths, discovered sound vibrations – Stephen Ian McIntosh (the harmonic lyre)
Harmony of the spheres – Plato
· Way to tie in music and science
· All spheres of the solar system (planets) creating one large harmony
Harmonics
Music is a tool to scientifically explore the world: circles, spheres, etc
Cymatics: pattern of sounds in liquids, resonance happens
Timbre: Quality of a sound
· Ex. Makes each voice sound different
Filters:
· Only passes some frequency ranges
· Types of filters:
o Low pass: only allows frequencies belw a limit
o High pass: only allow frequencies above a limit
o Bandpass: filters frequencies between two limits
o Notch (Band-Reject): Passing all frequencies outside a range between two limits
Resonance: Frequencies that amplify each other, phases that line up with each other
Eingentone: In certain spaces, certain frequencies will resonate louder than others than any other frequencies
Week 5:
Quote: “Music was the main poetic metaphor for that which could not be preserved” - Walter Murch
· Before recording, music only existed if you put a band to work
· When finished, moment was gone, doesn’t exist anymore, never to be seen again
· Emphasizes how recording really captured music and sound
Signals and Storage
· Signal
o Converting sound waves into a form that can be captured
§ Ex. Using a transducer
o Useful forms: Mechanical energy, voltage
o Used little needles to etch into wax or vinyl, or computer from analog to digital
o Signal to noise ratio
§ Signal: one’s voice (main things)
§ Noise: background noise
§ Used to measure how good a mic is
· Uses Dynamic Range (or SNR)
o Ratio of loudest possible undistorted sound to quietest possible undistorted sound OR to noise level of mic/speaker
§ Higher the ratio, the less obtrusive the background noise is
§ Human hearing: ~120dB SPL
o Max Possible Dynamic range: given by audio bit depth
§ How many numbers we’re using to record highest and lowest sound
· Storage
o Medium that allows signal to be stored
§ Ex. Magnetic tape, optical track, digital encoding
Quote: “Recording technology changed the way we hear. Neutral technology does not exist.” – David Byrne, How music works
· Suddenly, you could replay something again
· Able to capture moments
History of audio recording
· Analogue representation
o The idea was that horn collects sound waves, imprint waves, then play it back
§ Ex. Edouard-Leon Scott de Martinville recording « Au clair de la lune »
· Phonautograph to get sound waves, put it through a horn attached to a diaphragm, stiff bristle vibrated which inscribed an image
· Sold many phonautographs to scientists, but made no profit
§ Ex. Thomas Edison
· Did it on metal foil, then used soft wax (1877, 1888)
§ Then came the reord player
· Vinyl, sturdy
· Less susceptible to changes
· Better medium for storing sound
· Needle traces sound waves
· Idea: Sound is a physical force
· Back in older days, one recorder records everything
o Modifications had to be made
§ Singer in front
§ Instruments behind
§ Stole horn stuck on violin to make it louder
§ Vibratos on violins because they could be louder
· Magnetic sound recorders
o Piano wire and wire ribbon, then magnetic tape
§ Magnetic tape: used from WWII up to the 1990s to record
· Casette reel tapes
· How it works: move transducer, generates electrical signal, run current through electromagnet, rearrange magnetic field (on recording setting), and draw it out
· Play: read field on tape, send as electrical impulse
o Ex. Rebox tape recorder
§ Did a lot of those original recordings
§ See page 21 on slides to see how it looks like inside
§ See page 22 to see how it’s edited (need to cut the tape, then tape back together!)
§ Studer A800 sound machine: arguably one of the most beautiful sounding tape machines
o Modulated by sound waves
· Digital wave/computers
o Used after 1990s to record
Overdubbing & Multitrack recording
· Created by the same person who invented the (I think electric) guitar (Les Paul)
· Record multiple tracks
o Useful for recording different instruments separately
Editing
· Art of editing: being able to “see” and build towards the whole while it’s still in parts
· Linear editing:
o Had to do this with analog tapes, films, digital tapes, destructive editing
§ Destructive quality: loss of quality at each copy
· Noise level got higher at each dubbing
· Non linear editing
o Edits can be made in any order
o Done by software editing tools (Ex. Protools)
o (Usually) Non destructive editing
· Audio editing
o Various operations on sound files
o Distortion effects
o Time domain effects
o Frequency domain effects
§ See slide 28 for detailed list of examples of above
Vibrato
· Used to colour a note
· Oscillations above and below the pitch of a note
o Consider age and style of music when deciding when to use vibrato, speed of vibrato, narrow or wide range is
Steps to recording, editing, mixing, mastering
· Recording
o Set up mics
o Record the sound (action)
· Editing
o Loading sounds
o Cutting sounds
o Preparing sounds
o Sequencing sounds
· Mixing (many tracks)
o Mixing sounds over many tracks
o Adjusting levels, pans
o Introducing effects
o Finalize track levels
o Equalize audio between tracks
· Mastering (final step, final trap)(essential to final edit a track, to make sure listeners get the experience we want them to)
o Apply noise reduction to certain sounds so that we can eliminate them (hums, hisses)
o Adjust stereo width
o Add local or global ambience
o Add reverb
o Dynamic expansion
o Dynamic compression
o Pead limit the tracks
Digital recording media
· Quality of Digital vs Tape
o Digital
§ No degradation (unless scratches or something physically damages your CD)
§ Always gets 0s and 1s (perfect replication)
o Tape
§ More degradation
· Ex. Magnetic Substance will wear tape down over time
· Ex. Needle may damage vinyl tracks
· Tape can have dust, cracks, etc
*Think about our experience of music now, how its different after recordings became so common
· John Philip Sousa (1854-1932)
o Critiqued how recording supplements performae
o Recording making people lose real, shared experience
Influence of world music
· Changed how people absorbed, were influenced by, and learning music
Important questions to consider about recordings
· Ownership of recordings
· Distribution of recordings
· Intellectual copyright
· Cultural Appropriation
o “Sound Crimes”
§ Ex. Led Zeppelin: took a lot of blues tunes, never gave credit
Tape recorder as a new instrument
· Ex. Étude aux chemins de fer
o Impressive for its ability to recreate train sound very nicely
Discreet Music
· By Brian Eno
· Originally intended for Robert Fripp (guitar player) to use as background music
· People enjoyed it, so he released on its own
· Added layers through delays
Week 6:
Sampling beats
· Classical composers take themes, use them to make other pieces from original pieces
· Creative act of reusing material
DJ Spooky
· Sampler
· Creates beats out of things
· “Patterns of your mind with patterns in the world around you”
· “Music in information, information is music”
· “Walking down the street, listening to music, all this stuff is in the air”,
o Idea that we can’t comment or use this stuff in the air that we live with, music that surrounds us, we can’t use it as artistic material is very restrictive
“When sampling, transform things enough so it doesn’t sound like the original”
· Ethics, morals involved
· No stealing from others financially
Kenaxis
· Digital board used to play sound
· Control board plays sound from laptop software
Microphones
· Kind of transducer
o Sound vibrations hit the mic
o Spring goes back and forth
o Pressure waves into electric signals
o Mic plays these signals
· Different kinds of mics
o Pickup for a guitar
o Contact microphones
o Arm of a retro player
· Transducer
o Mic to speak, mic to produce sound
§ Apartment telecoms work as both a mic and a speaker
§ Headphones can also be both
· Three types of microphones
o Dynamic
§ Sound waves cause movement about a thin metallic diaphragm coil of wire, that moves a magnet changes acoustic energy to electronic energy
§ Identifying factors
· Inexpensive
· Durable
· Not sensitive to changes in humidity
· Don’t need external power to operate
· Resonant peak in mid frequency response
· Weak in high frequency beyond 10 kHz
§ Applications
· Sound reinforcement
· Snare drum miking
· Guitar miking
· Voice Overs
· Broadcasts
o Condenser
§ Two electrically charged plates, one moves, one fixed, sound wave varies through electric charge instead of moving through magnet
§ Responds faster
§ Good for high frequency sounds
§ Two versions
· Small diaphragm
o Single pickup pattern
o Relatively lower frequency response
· Large diaphragm
o Multiple pickup patterns
o Relatively higher frequency response
§ Need internal or external power to operate
· Phantom power
· Vacuum
§ Identifying characteristics
· Extended low and high frequency response
· (Good ones) Are somewhat expensive
· Need internal or external power
· Large diaphragm models can be bulky
· (Cheap ones) Can suffer from poor or inconsistent frequency response
· Humidity and temperature affect performance
§ Applications (used for miking)
· Cymbals
· Drum overhead
· Piano
· Acoustic guitar
· Vocals
· String sections
o Ribbon
§ Similar to a dynamic mic
§ Uses aluminum foil instead of coil of wire
§ Moves quickly and responds to acoustic & high frequency sound well
· Mic has a weaker output signal than dynamic as a result because foil is so thin
§ Very fragile
§ Identifying characteristics
· Relatively flat frequency response
· Have better high frequency response than dynamic mics
· Don’t need external power to operate
· Fragile
· Moderately expensive
§ Applications
· Miking cymbals
· Miking piano
· Miking bass
· Electric and acoustic guitars
· Brass instruments
· Patterns
o Directional response of microphone
§ How a mic responds to sounds coming from different directions around it
§ Recorded on a polar diagram (think polar curves in calc)
· Shows signal pickup level in dB in different frequency ranges
· All mics have different patterns
· 4 common patterns
o Omnidirectional mics
§ Mics up sound in all different directions
§ Frequency different though
§ 0 degree (circle)
o Cardioid mics
§ Picks up best from front of mic, but still picks up in all directions
§ Heart shape pattern
§ 131 degrees
o Supercardioid mic
§ Heart with a oval at bottom middle
§ 115 degrees
o Hypercardioid mic
§ More directional version of cardioid mic
§ Less sensitive to sound from its sides
§ 105 degrees
o Figure 8 (bidirectional)
§ Pick equally up from front and back, nearly nothing to side
§ 90 degrees (figure 8)
· Accessories
o Shock mount
§ Used to prevent vibrations from excess sound
o Boom pole
§ Enables you to hold mic up high
§ Gets sound from someone talking
§ Commonly used in films
§ Person holds pole
o Wind screen
§ Stops big waves of sound made by certain sounds from entering the mic as really loud sounds
§ Examples
· “p”s (big puff of air when saying “p”s)
· Placement
o Mic mistakes
§ Too many
§ Using wrong mic
§ Hanging mic in front of amp
§ Using old mic clips
§ Improper mic storage
§ Not cleaning vocal mic
§ Not knowing what sound you want
§ Bad mic placement
§ Cupping the mic head
o Go and hear from same position as mic
§ Mic is bionic ear
Preamp
· Amplify sound
Mixing board
· Mixes sound assigned to various track
Cables
· Maximize signal to noise ratio
o Strength of signal relative to background noise
· Two types
o Unbalanced
§ Signal transported by only one core per channel
§ Positive and ground only
§ Tip and sleeve
o Balanced
§ Positive, negative, ground
§ Signal transported by two cores per channel and out of phase
§ Tip, ring and sleeve
Audio connectors
· Adapters
DAC (Digital to Analog Converter)
· Device used for converting a digital code (normally binary) to an analog signal (current, voltage, electric charge)
o Filters (smoothing) help make a waveform sound like the original
· Digital
o Rectangular lines
o Similar to a Bar chart
· Analog
o Smooth wave
ADC (analog to digital converter)
· Box used to convert back and forth
DAW (digital audio workstation)
· Software that allows you to play with audio waves