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Flashcards

PSY247 Lecture 2 Audition 1

mark k English 45 cards

Cards in this deck (45)

  1. 1Sound WavesVibrations causing waves in the air consisting of
    Compressions &
    Rarefactions
  2. 2PeriodicComplex waveforms which repeat
  3. 3FrequencyAmount of full waves in a second (Hz)
    -Pitch
  4. 4AmplitudeMaximum distance of the wave from the mean position (axis)
    -Loudness (dB)
  5. 5Unit of LoudnessDecibels (dB)
  6. 6PhaseLocation in the wave (degrees)
    -Complete cycle is 360 degrees
    -Waves start at mean position at 0 degrees
    =Changes in quality percept of sound??
  7. 7LinearitySound waves add together logically
    -Sum of values at each point
  8. 8Fourier analysisDeconstructing a complex sound into its component sine waves
  9. 9FundamentalLowest frequency in a complex wave
    -Pitch percept
  10. 10HarmonicsPartials in a complex sound with wavelengths that are multiples of the fundamental
  11. 11SpectrumScatter plot graph of complex sounds
    (X) - Frequency
    (y) - Amplitude
  12. 12PinnaOuter ear
  13. 13MeatusEar canal
  14. 14Effects of PinnaShape and size amplifies mid frequency sounds (1600-7000Hz)
  15. 15EardrumTympanic membrane
    -Collects sound energy
  16. 16OssiclesMalleus, Incus, Stapes
    (Hammer, anvil, stirrups)
    3 bones that transfer sound energy from the tympanic membrane to the oval window
  17. 17Outer earPinna & Meatus
  18. 18Middle earEardrum & Ossicles
  19. 19Inner earCochlea
  20. 20Cochlea is filled with...Fluid (Perilymph & Endolymph) which cannot be compressed easily
  21. 21Round WindowFlexible membrane which allows energy to leave the cochlea
  22. 22Oval windowFlexible membrane that allows energy to enter the cochlea
  23. 23Vestibular CanalCompartment of the cochlea attached to the round window, filled with perilymph
  24. 24Reissner's membraneMembrane between vestibular canal and middle canal
  25. 25Middle CanalMid compartment of the cochlea
    filled with endolymph
  26. 26Tympanic CanalCompartment of the cochlea connected to the round window
    Filled with perilymph
  27. 27Basilar membraneMembrane between middle canal and tympanic canal,
    Thin and stiff near the base and floppy and wide near the apex,
    Contains the organ of corti
  28. 28Range of human hearing20-20,000Hz
  29. 29Intensity codingAuditory nerves have a spontaneous rate
    -High spontaneous rate fibres respond to lower intensities, at higher intensities they become "saturated" and cannot increase firing
    -Low spontaneous rate fibres respond to higher intensities
    -Outer hair cells amplify low intensity sound
  30. 30Tonotopic organisationPrimary auditory cortex is organised in an orderly progression of frequency (corresponding to basilar membrane)
    (Low frequencies at the bottom)
    (High freqs at the top)
  31. 31Fourier theory (3 rules)-Output must not contain new frequencies
    -Amplitude changes must be preserved
    -Output A+B+C must equal output A + output B + output C
    => filters meeting these rules are linear
  32. 32Non-linearity of the ear (3 properties)-Very close tones are merged by the ear (Two-tone suppression)
    -Extra frequencies added (otoacoustic emissions)
    -Outer hair cells amplify low intensity sounds
  33. 33Otoacoustic emissionsfrequencies added by the inner ear to the perceived sound
  34. 34Two tone suppressionThe ear merges two very close tones into one
  35. 35EfferentNerve travelling outward from the CNS
  36. 36AfferentNerve fibre travelling inward to the CNS
  37. 37Outer hair cellsReceive efferent projections from auditory cortex, change their length in response
    (motile response)
    =>Involved in auditory attention and amplification
  38. 38Problems with place theory-Basilar membrane must have different tension along its length
    => Basilar membrane has no tension
    -Cannot explain pitch discrimination at high freqs
  39. 39Missing fundamentalPeople perceive the fundamental pitch of complex sounds, even when the fundamental is removed
    =>place theory cannot account for this
  40. 40Timing theoryPhase locking for tones of up to 1Hz for individual fibres (max rate individual fibres can fire)
    Up to ~4Hz, multiple phase locked fibres determine pitch using the Volley principle
    -Freq is perceived as the firing rate or combined volleying rate of hair cells
  41. 41BeatingAt higher frequencies, two harmonics can fit into the wider bandwidths of auditory filters
  42. 42Unresolved harmonicsHigher frequency waves that fit into the same auditory filter, causing beating
  43. 43Residue pitchThe frequency of beats from unresolved harmonics, same as the fundamental
  44. 44Problem with timing theoryMissing fundamental heard from artificial waveform containing one fundamental for resolved (lower) waves and one for unresolved (higher) waves was from the resolved waves.
    The theory cannot account for this
  45. 45Pattern theory of pitch perception-Complex sounds analysed using place code
    -Brain finds best fitting harmonic series
    =>Accounts for missing fundamentals and preference for resolved harmonics
    =>Cannot account for residue pitch

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Flashcards on PSY247 Lecture 2 Audition 1, created by mark k on 18/04/2015.
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mark k
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