1. Psychoacoustics: Sound Perception
Physics of Music, Spring 2018

2. Key Terms Place theory of hearing Critical band Sharpening
Just Noticeable Difference (JND)
Ohm’s Law of Hearing
Attack and decay transients
Pitch tracking
Missing fundamental
Binaural Effects

3. How do we “hear”?

4. Anatomy and Physiology: Form and Function
Video produced by Brandon Pletsch, Univ. of Georgia Medical School
URL:

5. Auditory system: Amazing facts
~10 octave range (20 – 20,000 Hz)
Ear senses changes 1 part of 10,000,000,000 of atmospheric pressure

6. Auditory Cortex
Saenz Auditory Neuorscience Group:
Reference:
URL:

7. Place Theory
Different frequencies excite specific regions (bands) in the cochlea
Critical
band
Images from:

8. Basilar membrane mechanical properties

9. sharpening Outer Hair Cell Elongating/Vibrating

10. Neural code of sound intensity

11. JND
Change in value of a variable (frequency, intensity) between two tones such that the difference just noticeable.
For instance: Can you tell the difference between:
440.0 vs Hz?
440 vs 441 Hz?
440 vs 444?
DEMO 17 on Auditory Demonstrations CD

12. Decibel scale Perceived sound intensity Pressure variation amplitude
Threshold pressure for hearing:
Image credit: Dreamstime.com

13. Equal Loudness Curve

14. Subjective Loudness Sensitivity depends on frequency
JE’s Equal loudness Curve

15. Ohm’s Law of Hearing
“Sound quality of a complex tone depends only on the amplitude of harmonics, not their phase”
Image and sound file source:

16. Attack Transients
“Once one knows the proportions of the different frequency components, one knows the timbre”
“Turning on” phase is
very important for
sound perception
Also, see Demo 29 on Auditory Demonstrations CD

17. Missing fundamental You play these…. Brain fills in this…
Demos 20 and 21 on Auditory Acoustics CD

18. Forwards and Backwards

19. Masking Alien enjoying cocktail party?!
Echoes cancelled….
How do we pick out one voice amongst all the other masking sounds?
Masking: existence of one tone interfering with perception of another tone.

20. Binaural Effects
Brain processes Relative timing of sound waves at Left and Right ears

21. Rhythmic variation