Soundscape and Psychoacoustics Using the resources for ...dependent sensitivity of human hearing;...
Transcript of Soundscape and Psychoacoustics Using the resources for ...dependent sensitivity of human hearing;...
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 1
Roland Sottek
HEAD acoustics GmbH
Soundscape and Psychoacoustics –
Using the resources for environmental noise
protection
Standards in Psychoacoustics
Satellite symposium on August 25 and 26, 2016
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 2
Introduction
The evaluation and design of noise is becoming increasingly
important.
Different kind of sources contribute to the noise:
Broadband and narrowband noises, tonal components, modulated
sounds.
The perception is often predicted by psychoacoustic parameters in
order to reduce time-consuming listening tests.
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Why do we need psychoacoustics?
Almost identical levels and
3rd octave spectra
of an electrical motor and a Mozart concert
Time data and 3rd octave spectrum
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Different time structures
Almost identical
3rd octave spectra and
thus identical sound
pressure levels and
stationary loudness
values (calculation from
3rd octave spectra)
Clearly audible
difference also with
respect to loudness
because of different
time structures
40
50
60
80
L/d
B[S
PL
]
f/Hz20 100 2000 20k
Noise
40
50
60
80
L/d
B[S
PL
]
f/Hz20 100 2000 20k
Impulse
40
50
60
80
L/d
B[S
PL
]
f/Hz20 100 2000 20k
Diesel
3rd octave spectra
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Same sound pressure levels – different loudness values
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sound frequency /
Hz
modulation-
rate / Hz
fluctuation roughness
1000 0
1000 1
1000 4
1000 20
1000 70
1000 & 2000 0
Modulated signals, tone complexes
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Perception and physical measurement
„Optical illusion“
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“Acoustical illusion” („signal-estimation“)
fre
qu
en
cy
timetime
pulsation thresholds
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Acoustics vs. psychoacoustics (1)
In acoustics the sound source is in the center of focus:
What signals? What are the amplitudes? What vibrations /
frequencies? What energy?
Psychoacoustics provides the recipient (the people) in the center
of focus :
What loudness, sharpness, roughness, tonality, annoyance are
perceived?
What are the expectations, attitudes, experiences of those affected?
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 11
Acoustics vs. psychoacoustics (2)
In acoustics, the entire sound event is often reduced to a simple
variable in the form of A-weighted sound pressure level dB (A).
A-weighting considers in a highly simplified manner, the frequency-
dependent sensitivity of human hearing; low-frequency tones are
perceived softer as high-frequency tones at the same sound
pressure level.
Psychoacoustics describes the auditory sensation of a human
being as a complex function of the signal composition, the
temporal patterns, the interaction of different frequencies.
Here cognitive and contextual aspects are very important: attitude
to noise, the information content and the cause of the noise.
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What is psychoacoustics?
Psychoacoustics deals with the sound perception of human
hearing (sound recording, analysis in the inner ear, processing
and analysis in the brain) and is engaged in addition also with the
acoustically correct recording (e.g., with an artificial head
measuring system) and the hearing-related analysis of sound
events.
Taking into account the cognitive aspects of noise
psychoacoustics enables one to describe the transformation of a
sound event in an auditory event.
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Introduction to loudness
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 15Was ist Lautheit?André Fiebig 15
Definition of loudness
„Loudness is a psychological term used to describe the
magnitude of an auditory sensation.“ * (Fletcher, Munson, 1933)
„Die Empfindungsgröße der zur Schallstärke gehörenden
Intensitätsempfindung ist die Lautheit.“** (Zwicker, 1982)
(The auditory sensation corresponding to the perceived sound
intensity is loudness.)
* FLETCHER, H. MUNSON, W.A.
Loudness, its definition, measurement, and calculation. J. Acoust. Soc. Amer. 5, p. 82 (1933)
** ZWICKER, E.
Psychoakustik. Hochschultext, Heidelberg, New York, Berlin, Springer Verlag, p. 79. (1982)
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Sound Sound
Influence of masking on loudness
N5=10,6 sone GF N5=13,5 sone GF
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 17
Influence of duration on loudness (temporal integration)
Nmax=8,5 sone
Nmax=14,0 sone
Nmax=16,4 sone
Tone pulse
Tone pulse
Tone pulse
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Factors influencing loudness
Frequency Tones with the same sound pressure level but different frequency are not
perceived as equal loud.
Spectral composition Sounds with different spectral composition but the same sound pressure
level are not perceived equally loud, e.g. broadband sounds are perceived louder than narrowband sounds at the same level.
Sound pressure level Changes in sound pressure level do not lead to the same degree to
loudness changes.
Simultaneous masking At the same level, loudness varies by different masking effects in the
spectral domain.
Backward and forward masking The temporal structure is influencing the perceived loudness (test tone is
presented before or after the masker).
Signal duration Loudness sensation increases with signal duration up to a duration of 1 s.
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 19
Critical band concept
Critical bandwidth can be considered as the bandwidth of auditory
filters.
Critical bandwidth is constant below 500 Hz and is about 20 % of
the center frequency at higher frequencies.
Third octave filters have a similar bandwidth, thus they can "be
considered as a useful approach to auditory filters“ *
The concept of critical bands is for many auditory sensations of
particular importance.
dB(A) does not consider critical bands and masking!
*FASTL, H.
Psychoakustische Methoden, in: Kalivoda, M.T. und Steiner (Hrsg.). Taschenbuch der Angewandten Psychoakustik, Wien,
New York, Springer (1998)
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Loudness standards
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 21
Standardization of psychoacoustic parameters (1)
Loudness evaluation has become a central focus for assuring better
consideration of sound intensity phenomena than frequency-weighted
levels like dB(A).
Different loudness standards available for stationary sounds:
ISO 532:1975 section 1 (method A) [Stevens method]
ISO 532:1975 section 2 (method B) [Zwicker method]
ANSI S3.4:2007 [Moore/Glasberg method]
DIN 45631:1991 [Zwicker method]
Loudness standard available for time-varying sounds:
DIN 45631/A1:2010 [Zwicker method]
WG 9 of ISO TC43 (Acoustics) has worked on (available end of 2016)
• ISO 532-1 “Methods for calculating loudness – Part 1: Zwicker method”
for stationary and time-varying sound based on DIN and
• ISO 532-2 “Methods for calculating loudness – Part 2: Moore/Glasberg
method” for stationary sounds based on ANSI S3.4:2007.
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History of loudness standardization (Zwicker method)
DIN 45631: 1967 stationary loudness
ISO 532B : 1975 stationary loudness
DIN 45631: 1991 stationary loudness widely used!
corrections to match the ISO equal
loudness contours (ISO 226:1987)
DIN 45631/A1: 2010 time-varying loudness widely used!
ISO 532-1: 2016 stationary and time-varying loudness
based on DIN 45631, but with test
implementation (source code in appendix),
detailed description from time signal to
(specific) loudness vs. time function;
nearly identical results can be obtained
by ISO 532-1 and DIN 45631 or DIN 45631/A1
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 23
History of loudness standardization (Moore/Glasberg method)
ANSI S3.4: 2007 stationary loudness
ISO 532-2: 2016 stationary loudness, based on ANSI S3.4
The ISO 532-2 method does not fully
describe obtaining a result from time-signals,
only from described levels versus frequencies.
User interaction is required: description of
tones, noise bands, …!
Moore/Glasberg made the source code of their
loudness model available as part of ISO 532-2.
A time-varying loudness model is planned
for a later update.
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Standardization of psychoacoustic parameters (2)
Sharpness standard (the weighted first moment of the critical-band
rate distribution of specific loudness, only stationary signals):
DIN 45692 (2009)
Tonality standards: ECMA-74 (IT products), DIN 45681
Standardization of roughness is currently being pursued in a DIN
working group.
Following:
Overview of loudness calculation procedures
Sharpness calculation procedure
Tonality calculation procedure
Roughness model discussed as one option in the DIN working group
Blind source separation
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Loudness calculation procedures
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Loudness calculation procedures
p(t)FF
DF
LP N´ NL
LP
g1
+ N(t)
LP N´ NLg2
LP N´ NLgk
LP N´ NLgK
band pass
filter bank
Bark(Zwicker)
ERB(ANSI)
3rd Oct.(DIN)
?
p(t)FF
DF
LP N´ NL
LP
g1
+ N(t)
LP N´ NLg2
LP N´ NLgk
LP N´ NLgK
band pass
filter bank
Bark(Zwicker)
Bark(Zwicker)
ERB(ANSI)
ERB(ANSI)
3rd Oct.(DIN)
3rd Oct.(DIN)
??
temporal effects and post-masking
(DIN 45631/A1)
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Comparison: ANSI - DIN
ANSI S3.4-2007 DIN 45631
Choice of sound field Free or diffuse
Band pass filter bank 40 filters, constant band-
width on ERB scale
28 third-octave filters,
approx. 24 Bark bands
Envelope formation Rectifying and low-pass filtering
Frequency weighting Strong attenuation Less attenuation
Nonlinearity Square root law between sound pressure and
loudness (highly simplified)
Opposite effects!
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 29
Equal-loudness contours (60 phon)
Equal-loudness contours (60 phon): IS0 226 new/old, DIN 45631, ANSI S3.4-2007 L/dB[SPL]
40
50
60
70
80
90
100
110
120
f/Hz20 50 100 200 1000 2000 5000 10k
ISO 226: 2003ISO 226: 1987DIN 45631ANSI S3.4-2007
Tones are judged much softer by ANSI S3.4-2007 than DIN 45631!
≈ 8 dB
GENUIT, K., SOTTEK, R. AND FIEBIG, A., Comparison of Loudness Calculation Procedures in the Context of Different
Practical Applications, Internoise 2009, Ottawa, Canada (2009).
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Loudness of technical sounds
DIN 45631 and ANSI S3.4-2007 standards provide significantly
different loudness values in many cases!
6.8 sone
28.3 sone
25.7 sone
6.2 sone
23.8 sone
37.9 sone
29.8 sone
28.9 sone
4.7 soneGF
25.4 soneGF
24.1 soneGF
4.6 soneGF
18.7 soneGF
30.6 soneGF
23.2 soneGF
28.8 soneGF
electric motor
wind noise
vehicle noise at constant speed
power seat
park (New York)
electric screwdriver
electric saw
exhaust system
ANSI S3.4-2007DIN 45631sound source
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 31
Signal processing scheme: time-variant loudness (ISO 532-1)
z = z + step sizefalse
Inp
ut sig
na
l
LCB‘ 1
Core loudness
N‘C 1 (eq. A.1.1)
slope loudness > specific loudness
Specific loudness = core
loudness x
Specific loudness = slope
loudness
Total loudness
Mapping to 24 critical bands (Bark) using table A.6
Specific loudness = core loudness x
Summation of specific loudness
Start index z = 0.1 Bark. Step size = 0.1 Bark. Approximated
core loudness, filter number: x = 1
z < 24
Calculation of slope loudness using
table A.7
falsetrue
true
Step to next
CB: x(z)
true
false
Weighting
(table A.1)
LCB‘ 2
LCB‘ 3
LCB‘ 4
LCB‘ i
LCB‘ 20
Weighting
(table A.1)
Weighting
(table A.1)
Weighting
(table A.1)
Weighting
(table A.1)
Weighting
(table A.1)
Weighting
(table A.1)
Weighting
(table A.1)
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
Core loudness
N‘C 2 (eq. A.1.1)
Core loudness
N‘C 3 (eq. A.1.1)
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
Core loudness
N‘C 4 (eq. A.1.1)
Core loudness
N‘C i (eq. A.1.1)
Core loudness
N‘C 20 (eq. A.1.1)
NL
NL
NL
NL
NL
LP1
Applicaton to ISO 532-1 method B
LPi
LP6
LP7
LP8
LP9
LP10
LP11
LP12
LPi
LP28
NL
f
25 HzA
f
3rd octaveA
f
80 HzA
f
125 HZA
f
100 HzA
f
250 HzA
f
200 HzA
315 HzA
f
3rd octaveA
f
12500 HZA
f
160 HZA
f
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
Level corrections
a0 ,DLDF, DLCB
(tables A.2-A.5)
LT 1
LT i
LT 6
LT 7
LT 8
LT 9
LT 10
LT 11
LT 12
LT i
LT 28
t=70 msLP1 LP2
0.530.47
t=3.5 ms
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 32
ISO 532-1
Reducing uncertainties in loudness calculation of time-variant sounds
In addition to the loudness standard for stationary sounds:
Specification of the third-octave filter bank
Rectification and intensity averaging
Non-linear temporal decay of the hearing system
Temporal weighting of total loudness
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 33
Temporal weighting of total loudness
Two 1st order low-pass filters (time constants 3.5 ms and 70 ms)
applied to sum of specific loudness values
Simulates duration dependent behavior of loudness perception for
short impulses: signal with duration of 10 ms is perceived as about
half as loud as one with duration of 100 ms
Total loudness is weighted sum (factors 0.47 and 0.53) of filtered
signal
t=70 msLP1 LP2
0.530.47
t=3.5 ms
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 39
Representative value for time-variant loudness?
N5 percentile of loudness vs. time representation
Considers peaks -> better than mean value
Especially in the case of many events (cognitive effects)
Even better: root mean cubed average of loudness vs. time function
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 40
Representative value for time-variant loudness?
N5 not suited for impulses:
For this special case only: maximum value
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 41
Summary and conclusion (loudness calculation procedures)
Application of ANSI S3.4-2007 and DIN 45631 standards to technical
sounds provides significantly different loudness values
3 factors influence strongly the results of loudness models
Frequency weighting (differences in equal-loudness-level contours
according to ISO 226:1985, 2003; especially a low frequencies;
new listening tests for normal equal-loudness-level contours
needed!)
Frequency scale (Bark, ERB)
Nonlinearity between sound pressure and spec. loudness
Presentation of an updated ISO 532 standard
Complete description of each signal processing step starting from wave
form to specific or total loudness vs. time functions
Code example for implementation of all algorithms will be available
Reduction of uncertainties in loudness calculation
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Sharpness calculation procedure
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 44
• Ratio of high frequency level to overall level (basic description).
• “Center of gravity,” on frequency scale of spectral envelope: the higher the “c.g.,” the sharper the sound.
• Integration of specific loudness multiplied by a weighting function, divided by total loudness (hence, sharpness is level-independent).
• Normalized to a reference sound, a narrow band of noise centered at 1 kHz at a level of 60 dB and a bandwidth of 160 Hz, which has an agreed value of 1 acum.
Sharpness
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 45
Calculation of sharpness (DIN 45692)
acum
d)('
dBark/)()('
Bark24
0
Bark24
0
z
z
z
z
zzN
zzzgzN
kS
Barkze
for
Barkz
zgBarkz 8,1585,015,0
8,151
)(8,15/42,0
Solid line:
weighting function according to
DIN 45692 (see above)
Dashed line:
weighting function according to
v. Bismarck
Weighting function according to
Aures depends on loudness N!
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 46
white noise, 8 kHz amplified
Sharpness vs. Time
Sharpness vs. Time
Comparison of sharpness methods: von Bismarck / Aures
white noise
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 47
Influence of time structure on sharpness
stream
stream „random“
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Tonality calculation procedure
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 50
Introduction to tonality
Technical and natural sounds often contain prominent tonal
components that can
significantly influence the individual perception and evaluation of the
sound event,
increase annoyance.
Tonality of sounds is increasingly important, even at very low levels
regarding
sound quality and sound design applications.
Products may emit tonally-perceived noises due not only to pure
tones but also to narrow noise bands, and to same-vicinity
combinations of pure tones and narrow elevated noise bands.
Established methods for tonality calculation such as (specific)
prominence ratio and tone to noise ratio exhibit problems when
compared to listening test data.
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Available tools for assessing audible tonality
Tone-to-Noise Ratio (TNR: ECMA-74; Information Technology main
use).
Prominence Ratio (PR: ECMA-74; Information Technology main use).
DIN 45681 tonality (German standard, 2006)
Psychoacoustic tonality (“Tonality”: Aures/Terhardt)
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 52
Perception of tonality
• Recent research results show a strong correlation between tonality
perception and the partial loudness of tonal sound components.
HANSEN, H., VERHEY, JL. AND WEBER, R.
The Magnitude of Tonal Content. A Review, Acta Acustica united with Acustica, Vol. 97, pp. 355-363 (2011).
HANSEN, H. AND WEBER, R.
Zum Verhältnis von Tonhaltigkeit und der partiellen Lautheit der tonalen Komponenten in Rauschen, Deutsche
Jahrestagung für Akustik, DAGA (2010).
VERHEY, JL. AND, STEFANOWICZ, S.
“Binaurale Tonhaltigkeit”, Deutsche Jahrestagung für Akustik, DAGA (2011).
KAMP, F.
Modellierung der Wahrnehmung tonaler Geräuschkomponenten (Modeling the perception of tonal sound components),
Master thesis (2012).
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 53
Pure tones (𝑓 = 1 𝑘𝐻𝑧) of different level in pink noise
80 75 70 65 60 55 50 45 400
2
4
6
8
10
12
Pegel des Rauschsignals [dB]
Kat
ego
rie
Pegel Sinuston = 70dB
mean value tonality
median value tonality
mean value loudness of tonal components
median value loudness of tonal components
35 40 45 55 65 750
2
4
6
8
10
12
tone level [dB]
cate
gory
sca
le
noise level = 60dB
45 50 55 65 750
2
4
6
8
10
12
tone level [dB]
noise level = 70dB
55 60 65 750
2
4
6
8
10
12
tone level [dB]
noise level = 80dB
The listening test has shown, that …… the perceived tonality and the loudness of the tonal content are
strongly correlated (for high noise levels).
SOTTEK, R., KAMP, F. AND FIEBIG, A.
A new hearing model approach to tonality, Internoise 2013, Innsbruck, (2013).
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 54
Hearing model (Sottek, dissertation, 1993)
SOTTEK, R.
Modelle zur Signalverarbeitung im menschlichen Gehör, Dissertation, RWTH Aachen (1993).
of a Door Slam Noise
Specific Roughness
Specific Loudness
Specific Fluctuation
a1
Channel 1
a i
Formation of Envelope
Ear-related Filterbank
a n
Channel n
0 0.1 0.2 0.3 0.4 s
Bark
0
5
10
15
20
Aurally-adequate Spectral Analysis
Outer and
Middle Ear
Filtering
Lowpass Nonlinearity
Auditory
SensationChannel i
Time Signal
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Extended nonlinearity of the hearing model (Sottek)
BIERBAUMS, T. UND SOTTEK, R.
Modellierung der zeitvarianten Lautheit mit einem Gehörmodell, DAGA ‘12, Darmstadt (2012).
EPSTEIN, M. AND FLORENTINE, M.
A test of the Equal-Loudness-Ratio hypothesis using cross-modality matching functions, J. Acoust. Soc. Am., vol. 118(2),
pp. 907–913 (2005).
ZWICKER, E.
Über psychologische und methodische Grundlagen der Lautheit, Acustica, vol. 8, pp. 237-258 (1958).
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 56
Double (half) loudness of a 1-kHz tone
Level increment (solid line) and decrement (dashed line) DL of a 1 kHz tone, required for double
and half-loudness perception (Zwicker). Mean values of 12 subjects and interquartile ranges of
the measurements are shown. Starting both parts of the experiment with the lowest level!
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 57
Two-dimensional pitch sensation
Analysis of excitation pattern in (x, τ)-plane allows for modeling psycho-
acoustic phenomena (e. g. difference tones, residual components)
LICKLIDER, J.C.R.
A Duplex Theory of Pitch Perception (1951).
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 58
Hearing model (Sottek) (basis)
time signal 𝑠(𝑡)
outer and middle ear filtering
i1 n
auditory filter bank with i=1..n critical bands
one-way rectification
attenuation
autocorrelation function (ACF)
more compressive non-linearity
i1 n
consideration of threshold in quiet
Example: door slam noise
t
SOTTEK, R.
Modelle zur Signalverarbeitung im menschlichen Gehör, Dissertation, RWTH Aachen (1993).
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Autocorrelation function of periodic signals
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-5
-4
-3
-2
-1
0
1
2
3
4
5x 10
-4
t / ms
ES
ES
ES
ES
ES
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-5
-4
-3
-2
-1
0
1
2
3
4
5x 10
-4
t / ms
ES
Pure tone, f = 1 kHz White noise, f = 20 Hz – 20 kHz
𝐸𝑠 = 𝜑𝑠𝑠𝐸 0𝐸𝑠 = 𝜑𝑠𝑠
𝐸 0 = 𝜑𝑠𝑠𝐸 𝑛 ∙ 𝑇
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 60
Delay time window
autocorrelation function of a tone in pink noise
0 20 40 60 80
-8
-4
0
4
8delay time window
t0
tStart
tEnd
delay time t / ms
Ende
detection of periodicities
separation of periodic
signals and noise
𝐸𝑠 = 𝜑𝑠𝑠𝐸 0
𝐸𝑡𝑜𝑛𝑎𝑙 = 𝑦 (𝜑𝑠𝑠𝐸 𝜏𝑠𝑡𝑎𝑟𝑡 𝑓 , 𝜏𝑒𝑛𝑑 𝑓
𝐸𝑠 ≥ 𝐸𝑡𝑜𝑛𝑎𝑙
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Frequency-modulated tone at 2 kHz (fmod=2 Hz, mi=150, L=30 dB)
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Roughness calculation procedure
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Extension to the third dimension
New algorithm:
(two dimensional: time-frequency) auditory filter bank
is extended by modulation spectral analysis to a tensor
Tensor contains information about
time, frequency and time structure (modulation rate).
frequency
time
t
hearing model
spectrogram
3rd dimension:
time structure
frequency weighting
weighting vs. t
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Internoise 2016, Hamburg - A hearing model approach to roughnessRoland Sottek 66
Model calibration according to Zwicker and Fastl
Internoise 2016, Hamburg - A hearing model approach to roughnessRoland Sottek 67
Roughness of tones (f=1 kHz, fmod=70 Hz, m=1)
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 68
Roughness of engine sounds
RI
Number of engine noise
Measurement
Simulation
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 69
Application of the hearing model roughness calculation
Klemenz (Dissertation ‘05)
Roughness compared to
dissonance
0
0,2
0,4
0,6
0,8
1
1 2 3 4 5 6 7 8
Number of engine noise
roughness
a
M1
M2
M3
M4
SGNB
Attia & Okker (DAGA ’95)
Comparison of different models for
the prediction of engine roughness
Comparison of calculated roughness with experimental results
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 70
Blind source separation
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 71
Investigations of methods for detecting acoustic patterns
Spectral or temporal structures (patterns) are significant for the
hearing impression.
Complex sound events are constructed from several of these
patterns.
In listening tests it can be observed that in the evaluation of
complex sound events often large variations occur, which point to
an individual focusing on one of these patterns.
For a better analysis and exploration of psychoacoustic
phenomena, therefore, an automatic detection and separation of
these patterns is sought by mathematical methods.
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 72
„Blind“ source separation using spectrograms
Spectrograms are level
representations as a function
of time and frequency.
Better frequency resolution
means worse time resolution,
and vice versa, i.e., depending
on the resolution temporal
structures are recognizable
and the representation in terms of frequencies can be smeared.
The two-dimensional representation is thus often inadequate for
the description and especially for the detection of patterns.
The quality of the results depends greatly on the signal and the
selected resolution.
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 73
Extension to the third dimension
New algorithm:
(two dimensional: time-frequency) auditory filter bank
is extended by modulation spectral analysis to a tensor
Tensor contains information about
time, frequency and time structure (modulation rate).
frequency
time
t
hearing model
spectrogram
3rd dimension:
time structure
frequency weighting
weighting vs. t
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 74
Separation of a mixture of modulated tones (example 1)
Good reconstruction of the modulated tones!
detected pattern 5
original detected pattern 1 detected pattern 2
detected pattern 3 detected pattern 4
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 75
Separation of a the patterns of a hard disc noise (example 2)
Different meaningful patterns can be detected.
detected pattern 5
original detected pattern 1 detected pattern 2
detected pattern 3 detected pattern 4
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Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 76
Conclusions and outlook
Summary of psychoacoustic parameters
Status of standardization
Hearing model approach of Sottek
Two-dimensional representations for the detection and separation
of the components are often not sufficient.
New method is based on three-dimensional modulation tensor.
Additional information about temporal structure
Based on a signal processing model of human perception
First results indicate that the method can extract patterns in technical
noise similar to the perceived patterns by humans.
Validation shall be performed in listening tests.
Outlook: possible application for soundscape projects
Internoise 2016, Hamburg & Berlin - Standards in PsychoacousticsRoland Sottek 77
Dr.-Ing. Roland Sottek
Manager Research NVH
www.head-acoustics.de
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