Digital audio and computer musicOverview1. Sound and musicWhat is sound?What do we hear?PsychoacousticsPowerPoint Presentation2. Representations of sound and musicSlide 9Digital representation of musicCompressionChoosing a representation3. Using technology to analyze sound and musicAnalyzing speechComputational Auditory Scene AnalysisMusic information retrievalMachine learning for analysis4. Using technology to create music and soundCreating music: SynthesisThree approaches to synthesisSlide 21Some continua of computer music creationPerformer-Computer InteractionQuestions: How can we….Final remarksSlide 26Digital audio and computer musicCOS 116: 2/26/2008Overview1. Sound and music in the physical world and in human experience2. Representations of music3. Analyzing music with computers4. Creating music with computers1. Sound and musicWhat is sound?Discussion Time“Pressure wave”What do we hear?Video: http://www.youtube.com/watch?v=0svoQcMQNYgFrequencyPitchLoudnessTimbre…PsychoacousticsRelationships between physical phenomenon of sound and our perceptionFrequency : pitch20-20,000HzAmplitude : loudnessIdentities and strengths of frequencies present : timbre+ =Discussion TimeWhat is music?“Organized sound” • Psychoacoustics play an important role• Also dependence upon history, culture, experience• Engages listeners’ psychological mechanisms for expectation/reward2. Representations of sound and musicScore: Audio samplesSpectrumDiscussion TimeHow do you represent music?Digital representation of musicCompressionA “better” representation with fewer bitsWhy? Security, transmission, storageHow?Psychoacoustic principlesMP3: MaskingPhysical principles of sound production (uses modelsof sound source)Choosing a representationRepresentations are compromisesStandard representations are somewhat arbitraryAppropriate representation is task-dependent3. Using technology to analyze sound and musicAnalyzing speechReal-life apps:Customer service phone routingVoice recognition softwareComputational Auditory Scene AnalysisApplications: Archival and retrieval, forensics, AIMusic information retrievalAnalyzing musical dataQuery, recommend, visualize, transcribe, detect plagiarism, follow along with a scoreSites you can trymidomi.comThemefinder.comPandora.com (human-driven), last.fmMachine learning for analysis4. Using technology to create music and soundA whirlwind tour of the 20th century, with a focus on computer technologyCreating music: SynthesisThree approaches to synthesisAdditive synthesis1. Figure out which frequencies are present, and in what proportions2. Synthesize a sine wave at each frequency, and superpose them.1. Physical modeling1. Start with knowledge about how physical systems oscillate2. Simulate oscillation of an arbitrary system. (RecallLecture 4)+ + …=Three approaches to synthesisCross-synthesisChoose filter for speech (vowel)Choose source to be another soundSome continua of computer music creationSynthesisControlling synthesisCompositionlowhighLevel of controlRunning a programComputer follows performerLive coding, special controllersInteractivityPerformer-Computer InteractionAugmented instrumentsSoftware and hardware interfacesDemo: PLOrk video, PBSDemo: using a Wii-mote to control soundDemo: SMELTNew instruments Demo: Perry’s MugLive codingDemo: Max’s drum machineQuestions: How can we….develop new ways to synthesize sound?give user control over synthesis parameters?make machines interactive in a musical way?augment human capabilities?design new instruments that are easy to play? allow expert musicality?create music that is emotionally and aesthetically compelling?Final remarksDistinctions in this presentation are superficialAnalysis, representation, and creation interactTechnology draws on and contributes to our understanding of the physics and psychophysics of soundComputer music is interdisciplinaryHCI, AI, programming languages, algorithms, systems buildingAlso psychology, music theory, acoustics, signal processing, engineering, physics, performance practice, library science, applied math & statistics, …Technology is constantly complicating and changing the landscape of our musical experiences as creators, participants, listeners, and consumers.http://soundlab.cs.princeton.edu/QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.QuickTime™ and aTIFF (LZW) decompressorare needed to see this
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