1 / 27

Auditory Perception

Auditory Perception. Class 8, Auditory Processing, Part 3. Outline. Oral Presentation Lab 2: Midway point Midterm Q&A class before exam. n/a. Review. How does the ear recover sound intensity loss from the air to water interface in the ear?. Text. Minimum audible field.

carolyn-ray
Télécharger la présentation

Auditory Perception

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Auditory Perception Class 8, Auditory Processing, Part 3

  2. Outline • Oral Presentation • Lab 2: Midway point • Midterm Q&A class before exam n/a

  3. Review • How does the ear recover sound intensity loss from the air to water interface in the ear? Text

  4. Minimum audible field Minimum audible pressure p 180

  5. Absolute Thresholds • Loudness • A sound cannot be loud • Our perception of the sound can be loud p 181

  6. Conversational speech What’s up here? Absolute Thresholds p 182

  7. Fundamental Concept • Psychometric vs Psychophysical functions • Psychometric • Function of a physical quantity and behaviour • Shows one threshold • Psychophysical • Function of two physical quantities • Shows how threshold on one physical quantity varies as a function of the other n.i.t.

  8. Question • What are these functions? Text

  9. Loudness • Other factors • Spatial integration: Binaural vs monaural presentation accounts for 6 dB difference • Temporal integration: Duration of sound: Threshold increases below 200 ms Text

  10. Fundamental Concept • Spatial and temporal integration • Any sensor must integrate (add up) signals across a certain range of space and time • Longer integration provides greater sensitivity but lower acuity (details are lost) • Recall the idea of “receptive fields” Text

  11. Difference Thresholds • Also vary with frequency • More than that: The Weber fraction also varies with frequency • Weber fraction also varies across intensities • Only constant? Across moderate intensities Text

  12. Difference Thresholds • Increased intensities create greater traveling waves on basilar membrane • Affects more neurons p 185

  13. Loudness • Closely related to intensity • Metric of loudness: sone p 186

  14. Loudness vs Frequency Text

  15. Masking • How hearing one sound affects the perception of another • Intensity and frequency masking Text

  16. Text

  17. Noise Masking • 2 methods: • Tonal masking Constant target frequency, varying noise frequency • Noise masking Varying target frequency, constant noise frequency Text

  18. Tonal Masking • Fixed test tone, say 1000 Hz at 40 dB • Series of masking tones of different frequencies presented • For each mask, the observer adjusts its intensity until it just drowns out the test tone Text

  19. Tonal Masking • Results shown for 1000 Hz test tone • Most effective mask = same frequency as tone • Masking not symmetric! Text

  20. Noise Masking • Constant mask is used • “Narrow-band” white noise • E.g., noise of 410±45Hz. Centre frequency of 410 Hz and a bandwidth of 90Hz Text

  21. Noise Masking • Effect of 410±45Hz noise mask on the absolute threshold • Done for test tones across frequency spectrum • Threshold most elevated for test tones near the frequency of the noise • Again, not symmetric Text

  22. Masking Asymmetry • How come? • The answer is on the basilar membrane • Characteristics of traveling wave: gradual build-up and sudden decay Text

  23. Perceptually... • Responses to test and masking tones: • more similar if the noise has lower frequency than test • more different if the mask is higher than test frequency Text

  24. Question • If the masking tone or is a 500 Hz, with 50 Hz bandwidth white noise • What frequency target tone will it most effectively mask? • Which target tone will it mask more -- 400 Hz or 600 Hz? • What’s the deal with asymmetry in masking? Text

  25. What is the difference between intensity and loudness? • What are the advantages and disadvantages of open-ear and closed-ear methods for measuring detection thresholds? • What are the psychological and physiological factors that account for the shape of the minimal audibility curve? Text

  26. How is the sone scale defined? • How is the phon scale different? Text

  27. What is the dynamic range of hearing? • Why was the sound of the drill in the other classroom especially annoying? Text

More Related