Gustav Mahler
(1860 – 1911)
Symphony #1 in D
Last Movement

Slide 2

Structure of The Ear
Outer Ear
Middle Ear
 Inner Ear

Slide 4

Slide 5

Slide 6

Hildegard von Bingen
(1098-1179)

Discrimination
Between Sounds
 Just Noticeable Difference
or
 JND

2AFC Testing
100 % correct ̃ Certainty
50% Correct ̃ Guess
Cutoff is defined for 75%

JND for SIL

JND for Frequency

Physical
Characteristics
 Intensity = I (W/m2)
 Sound Intensity
    Level = SIL (dB)

Psychological Characteristic
Loudness

Psychological Characteristic
For two sounds,
 A and B,
 if IA/IB = 2,
 what to we hear?

Psychological Characteristic
For two sounds,
 A and B,
 if SILA/SILB = 2,
 what to we hear?

Phon
The phon is the unit of
 Loudness Level
( LL)

Phon
  The LL (in phons) of a sound is  defined to be numerically equal to the SIL (in dB) of a 1000 Hz tone that sounds equally loud to the listener.

Physical
Characteristics
Frequency

Psychological Characteristic
Pitch

Pitch and
 Frequency
  If note A sounds twice as high in pitch as note B, it is found that the frequency of A is twice that of B.

Pitch and
 Frequency
Natural unit of pitch is the Octave.
Simple relationship between pitch and frequency.

Pitch and
 Frequency
Demo with keyboard.

Loudness
 and Frequency
  The loudness of a sound depends on the frequency of the sound.

Experiment
1. Play 1000 Hz at SIL=40 dB.
2. Play 100 Hz.  Ask listener to adjust for the same loudness.
3. Repeat for many frequencies

Experiment
   f(Hz)      SIL (dB)
      20          90
      50          64
    100          51
    500          38
  1000          40  defined
  1500          40
        f(Hz)      SIL (dB)
        2000          39
        4000          32
        6000          36
        8000          49
      10000          48
      15000          41

   Equal Loudness
   Contour

Loudness changes
with Frequency
Auditory Demo CD
Tracks 17 and 18

Resonance
Hearing is most sensitive in the range 2,500 – 5,000 Hz.  Why?
Ear canal is a tube closed at one end
l= 4L = 4(2.5 cm) = 10 cm
f = v/l = 344m/s /0.1m = 3,440 Hz!

Repeat for all SIL’s