1. Audio Scene Analysis and Music Cognitive Elements of Music Listening
Kevin D. Donohue
Databeam Professor
Electrical and Computer Engineering University of Kentucky

2. What is Music?
1 a : the science or art of ordering tones or sounds in succession, in combination, and in temporal relationships to produce a composition having unity and continuity b : vocal, instrumental, or mechanical sounds having rhythm, melody, or harmony
Merrian-Webster Online Dictionary:

3. Auditory Scene: Input
Sensory organs (ears) separate acoustic energy into frequency bands and convert band energy into neural firings
The auditory cortex receives the neural responses and abstracts an auditory scene.
Time
Frequency

4. Auditory Scene: Perception
Perception derives a useful representation of reality from sensory input.
Auditory Stream refers to a perceptual unit associated with a single happening (A.S. Bregman, 1990) .
Acoustic to Neural Conversion
Organize into Auditory Streams
Representation of Reality

5. Auditory Stream Experiment
Bergman & Campbell (1971)
Streams tend to form by grouping notes close in time and frequency (similarity and proximity).
Click on spectrograms to play tone sequence. Identify changes in tone grouping based on separation in time and frequency.
Note change in grouping/phrasing from inserting a pair of closely spaced tones around the lower tone.

6. Circularity in Pitch Judgement
Shepard’s Scale (1964)
(Auditory Demonstrations CD, from the Acoustical Society of America)

7. Perceptual Organization
Organization properties:
Belongingness – a sensory element belongs to an organization (or stream) of which is a part.
Exclusive allocation – a sensory element cannot belong to more than one organization at a time.
Bregman & Rudnicky (1975)
Click on spectrogram to listen to tone sequence. Note in first case the later tonal group sounds as one stream due to time proximity. In the second case flanking the lower tones with a sequence at same frequency, separates the lower tone from the upper tones creating 2 separate streams.

8. Perceptual Organization
Organization properties:
Closure – perceived continuity, a tendency to close strong perceptual forms, response to missing evidence.
Click on time waveform plots to listen. In the first case a low level tone is playing and then stops, but the gap is covered by a white noise mask. Most will hear the tone playing through the mask.
Tone pattern first spectrogram
White noise only, used in masking

9. Sequential and Spectral Integration
Sequential Integration
Grouping sensory elements over time or events at different times and considered as from the same source.
Melody, rhythm
Spectral Integration
Fusing simultaneous sensory elements over frequency into one
Timbre, harmony

10. Timbre and Spectral Integration
The time harmonic structure (spectral envelope) and time envelope give rise the timbre of the sound.
Click on spectra to hear sound. Note Impact of spectral and time envelopes

11. Timbre and Spectral Integration
Simultaneous tones grouped by timbre
Click on spectrograms to play sounds. Note that different spectral bands do not sound like different streams. Just one stream is heard.
Same Note (A)
2 Notes (F and A)

12. Auditory Scene Organization
Primitive Stream Segregation
Inherent constraints in auditory scene analysis (perceptual organization demonstrated by infants/children)
Music: Organization of musical sensory units
Schema-based segregation
Learned constraints in auditory scene analysis (differences in perceptual organization resulting from training and culture)
Music: Differences between musicians and non-musicians
Music: Differences resulting from acculturation
(A.S. Bregman, Auditory Scene Analysis, MIT Press 1990, pp. 1-45)

13. Music Related Terms
Pitch – Perceived frequency/fundamental tone (20Hz-20kHz Range)
Melody – Pattern of tones identified by the intervals between consecutive pitches
Contour – Shape of the melody without regard to intervals
Loudness – Perceived intensity of sound (0dB to 120dB)
Timbre – Nature of a sound defined mostly by its harmonic structure and time envelope
Rhythm – Repeated pattern of strong and weak sounds
Tempo – Rate of the rhythm

14. Melody Invariance
A melody can typically be recognized over changes in pitch, loudness, timbre, tempo, spatial location, and reverberations.
Contours are typically recalled better than actual melodies (intervals) for unfamiliar tunes. (Massaro, Kallman, and Kelly 1980).
(Daniel J. Levitin, Memory for Musical Attributes, in Music Cognition and Computerized Sound, ed. P.R. Cook, MIT Press, 1999, pp )

15. Primitive Musical Perception
Distinguish between cognitive components present at an early age and those resulting from acculturation.
Infant: Grasp of musical structures
Adult: Develop cognitive strategies for applying musical structures
(W. Jay Dowling, The Development of Music Perception and Cognition, The Psychology of Music Academic Press, 1999, pp )

16. Summary
Innate perceptual organization separates sounds from different sources. Grouping by pitch, contour, rhythm (phrasing), and timbre are exhibited by infants.
Acculturation refines melody distinctions and its relationship to harmonies and rhythms based on cultural scales and patterns.
Melodic memory is enhanced for melodies following note of a known scale.
Auditory scene analysis operations apply broadly to all sounds (speech, noise, music). Why some auditory streams become pleasurable/stimulating/interesting (music), and others are simply used to form a perception of reality is still not clear.

17. How many streams are there?

18. Interesting Websites Mind, Music, and Machine
Auditory Scene Analysis
Joe Wolfe’s Web Page