HEARING

MUSICAL ACOUSTICS

Science of SoundChapter 5

MUSICAL ACOUSTICS

RANGE OF HEARING

OUTER, MIDDLE, AND INNER EAR

THE COCHLEA

THE EAR

MIDDLE EAR:

THE OSSICLES

RESPONSE OF THE BASILAR MEMBRANE TO A PAIR OF TONES

AS THE INTERVAL DECREASES THEIR RESPONSE CURVES SHOW INCREASING OVERLAP

CRITICAL BANDWIDTH

CONSTANT AT LOW FREQUENCY BUT PROPORTIONAL TO f AT HIGH FREQUENCY

EAR FUNCTION

SOUND SOURCE LOCALIZATION

PRECEDENCE EFFECT

(Also called “Haas effect” or “Law of the first wave front”)

THE SOURCE IS PERCEIVED TO BE IN THE

DIRECTION FROM WHICH THE FIRST SOUND

ARRIVES, PROVIDED THAT:

1. Successive sounds arrive within ~ 35 ms;

2. Successive sounds have spectra and time envelopes

similar to the first sound;

3. Successive sounds are not too much louder than the

first sound.

LINEAR

LOGARITHMIC

LOGARITHMS AND POWERS

OF TEN

PRACTICE PROBLEMS (no calculator, please)

2.1x102 +1.4x10-2 =

3.0x108/300 =

log 8 =

log 2x107 =

log ½ =

log 1/5 =

log 200 =

log 400 =

log 500 =

SOLUTIONS TO PRACTICE PROBLEMS

2.1x102 +1.4x10-2 = 210 + 0.014 = 210.014

3.0x108/300 = 106

log 8 = log 23 = 3 log 2 = 0.903

log 2x107 = log 2 + log 107 = 7.301

log ½ = -log 2 = -0.301

log 1/5 = log 2/10 = 0.301-1 = -0.699

log 200 = log 2 + log 100 = 2.301

log 400 = log 2 + log 2 + log 100 = 2602

log 500 = log 1000 – log 2 = 3 – 0.301 = 2.699

DEPENDENCE OF SUBJECTIVE QUALITIES OF SOUND ON PHYSICAL PARAMETERS