Noise, Vibration, Harshness – Sound Quality Research Group S2015/Lecture 16 2015 92-455.pdf ·...
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Psychoacoustics and its Metrics A presentation by Dr. Colin Novak – NVH-SQ Group University of Windsor Noise, Vibration, Harshness – Sound Quality Research Group Copyright 2015 by Colin Novak. All rights reserved no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval, without the prior written permission of the author. Copyright ©2015, Colin Novak
Transcript of Noise, Vibration, Harshness – Sound Quality Research Group S2015/Lecture 16 2015 92-455.pdf ·...
Psychoacoustics and its Metrics
A presentation by Dr. Colin Novak – NVH-SQ GroupUniversity of Windsor
Noise, Vibration, Harshness –Sound Quality Research Group
Copyright 2015 by Colin Novak. All rights reserved no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval, without the prior written permission of the author.
Copyright ©2015, Colin Novak
OUTLINE
2
Noise, Vibration, Harshness – Sound Quality Research Group
• What is Loudness
• Sones and Phones
• Critical (Bark) Bands
• Masking Effects
• Temporal Processing of Sound
Notice: There will be no lecture on August 12, instead I will have office hours from 8:30 – 10:30 in my office, Room 101 CARE
Lecture 16
Auditory Field
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Noise, Vibration, Harshness – Sound Quality Research Group
140dB
120
100
80
60
40
20
0
0.02 0.05 0.1 0.2 0.5 1 2 5 10 20 kHz Frequency
Soun
d In
tens
ity L
evel
Soun
d Pr
essu
re L
evel
Thresholdin Quiet
Limit of Damage Risk
Threshold of Pain
Speech
Music
140dB
120
100
80
60
40
20
0
100
W
1
10-2
10-4
10-6
10-8
10-10
10-12
200
Pa
20
2
0.2
2·10-2
2·10-3
2·10-4
2·10-5
m2
Soun
d In
tens
ity
Soun
d Pr
essu
re
Lecture 16
Loudness
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Noise, Vibration, Harshness – Sound Quality Research Group
• Describes the ‘human perception of loudness’, not the sound pressure level (psychology + acoustics = psychoacoustics)
• Uses Sones rather than dB (ref 20μPa)
• Uses Bark bands (or ‘Critical Bands’) rather than Frequency on the ‘x axis’
• Audiological Masking
Frequency Masking
Pure tone
Broadband
Time Masking
• Takes into account the Temporal Processing of sounds
Lecture 16
Loudness Model
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Noise, Vibration, Harshness – Sound Quality Research Group
LE
60dB40200
0 4 8 12 20 24 Bark16
LG
60dB40200
0 4 8 12 20 24 Bark16
N’
2sone
1
0
BarkN = N’ dz
5 sone
0 4 8 12 20 24 Bark16
Schematic Illustration
Lecture 16
Equal Loudness Contours
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Noise, Vibration, Harshness – Sound Quality Research Group
Sound
pressure
level, Lp
(dB re 20 Pa)
120
100
80
60
40
20
Phon0102030405060708090
100110120130
20 Hz 100 Hz 1 kHz 10 kHzFrequency
Lecture 16
Loudness - Phones to Sones
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Noise, Vibration, Harshness – Sound Quality Research Group
Relation between loudness in sone and phon
A doubling in a sone value corresponds to a doubling in perceived loudness and a 10 dB increase in phon.
N = 2(P - 40)/10
P = 40 + 10 log2N
0 200,1 60 80 100 12040
0,20,3
123
102030
100200300
0,5
5
50
Loudness at 1000 Hz
Loudness (phons)
Loudness
(sones)
At 1000 Hz:
1 sone = 40 phon
2 sone = 50 phon
4 sone = 60 phon
Lecture 16
Frequency vs Critical Band
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Noise, Vibration, Harshness – Sound Quality Research Group
24
Bark
20
16
12
8
1k 2 k 8 k 16 kHzFrequency, f
z
4
0
zBark = 10-2 f
Hz
20 100 1k 10 kHz
zBark
= 9 + 4 ld fkHz
24
Bark
20
16
12
8
z
4
0
Lecture 16
Frequency vs Critical Band
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Noise, Vibration, Harshness – Sound Quality Research Group
Bark Band # Center Freq. Bandwidth Start Stop Equiv. 1/3 Octave Bands1 50 100 0 100 1.25 - 1002 150 100 100 200 100 - 2003 250 100 200 300 200 - 3154 350 100 300 400 315 - 4005 450 110 395 505 400 - 5006 570 120 510 630 500 - 6307 700 140 630 770 630 - 8008 840 150 765 915 8009 1000 160 920 1080 100010 1170 190 1075 1265 125011 1370 210 1265 1475 125012 1600 240 1480 1720 160013 1850 280 1710 1990 200014 2150 320 1990 2310 200015 2500 380 2310 2690 250016 2900 450 2675 3125 315017 3400 550 3125 3675 315018 4000 700 3650 4350 400019 4800 900 4350 5250 500020 5800 1100 5250 6350 630021 7000 1300 6350 7650 630022 8500 1800 7600 9400 800023 10500 2500 9250 11750 10k24 13500 3500 11750 15250 12.5k
69.02])1000/(*4.11[*7525 tff Lecture 16
Masking Patterns
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Noise, Vibration, Harshness – Sound Quality Research Group
80
dB60
40
20
0
0.02 0.05 0.1 0.2 0.5 1 2 5 10 20 kHz
2040
60
80
100 dB
LCB =
Masking patterns of narrow-band noise centered at 1 kHz witha bandwidth of 160 Hz at different levels LCB
Frequency of test tone, fT
Leve
l of t
est t
one,
LT
Lecture 16
Masking Patterns
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Noise, Vibration, Harshness – Sound Quality Research Group
60
dB
40
20
0
0 2 4Critical-band rate
8 10 12 14 16 18 20 24 Bark
Thre
shol
d, e
xcita
tion
leve
l
6 22
0.250.07 0.5 1 fm = 2 kHz 4 8
Patterns of Narrow-band Noises Centredat Different Frequencies fm
Lecture 16
Post Masking
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Noise, Vibration, Harshness – Sound Quality Research Group
100dB
80
60
40
1 2 5
Delay time, td
20 50 100 200 500 1000 ms
Peak
Lev
el
= 10ms
40
60
LWN = 80 dB
0.5st
10
td
Lecture 16
Post Masking
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Noise, Vibration, Harshness – Sound Quality Research Group
Test-tone burst: fT = 2 kHz200 ms
t
5 ms
td
t
5 ms5 ms
td
60
dB
40
20
0 5Delay time, td
20 50 100 200 500 ms
Leve
l, L T
, of
test
-tone
bur
st
TM = 200 ms
10
TM = 5 ms
Lecture 16
Loudness vs Impulse Duration
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Noise, Vibration, Harshness – Sound Quality Research Group
LN
60
phon
55
50
40
Dependence of loudness level on impulse duration in comparison to measurements
45LA
60dB(A)
55
50
40
45
1 10 100 1000 ms
Ti
impulse
fast
slow
Lecture 16
Temporal Processing
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Noise, Vibration, Harshness – Sound Quality Research Group
N
32sone
24168
0 50 100 150 200
N’
10
Pa
5
0
b
0.6
0
-0.6
soneBark
p
c
a
0
250 300 ms tLecture 16
Final Exam
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Noise, Vibration, Harshness – Sound Quality Research Group
Lecture 16
