DENORMS TRAINING SCHOOL 3 “Experimental techniques for acoustic porous materials and metamaterials” 4 – 6 December 2017, Le Mans
Introduction to psychoacoustics and psychoacoustic tests Assoc. Prof. Kristian Jambrošić, PhD
[email protected] University of Zagreb, Croatia Faculty of Electrical Engineering and Computing Motivation
Physics is just something we measure. Reality is what we perceive. Jens Blauert
2 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Contents
. Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
3 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
4 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Anatomy of the ear
. Our sense of hearing = ear + auditory center in the brain . Parts of the ear: . outer ear . middle ear . inner ear
hearing process
5 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Hearing process
. Basics of the hearing process: . Sound waves enter the ear through the pinna and the ear canal which causes the eardrum to move. . The eardrum vibrates with sound, very similar to a membrane of a microphone. . Sound vibrations move through the ossicles to the cochlea like a system of leavers. . Sound vibrations cause the fluid in the cochlea to move forth and back (movements equalized by the round window). . Fluid movement causes the hair cells to bend. Hair cells create neural signals which are picked up by the auditory nerve. Hair cells at one end of the cochlea send low pitch sound information and hair cells at the other end send high pitch sound information. . The auditory nerve sends signals to the brain where they are interpreted as sounds.
6 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Middle ear
. Middle ear is responsible for sound conduction, but also for the acoustic reflex (protective mechanism)
7 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Inner ear
8 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Organ of Corti
9 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Frequency selectivity of the Cochlea
© Fastl, Zwicker: “Psychoacoustics”
10 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Neural response of the auditory nerve
. The amplitude (intensity) of the perceived sound wave is coded in auditory nerve firing impulses . Higher amplitude is coded with higher firing rate!
11 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests © Gelfand: “Hearing” Hearing threshold
. Average hearing threshold of human
12 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Hearing threshold
. What is the lowest sound pressure we COULD hear? . Brown noise – movement of the air molecules , constant noise at about -20 to -30 dB at mid freuqencies!
13 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Hearing threshold
. Hearing threshold for other marine and land mammals:
14 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Hearing threshold
. Highest audible frequency versus interaural distance:
© http://acousticstoday.org/wp-content/uploads/2016/01/The- 15 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Evolution-of-Mammalian-Sound-Localization.pdf Hearing threshold
. Hearing vs. vision for some mammals
© http://acousticstoday.org/wp-content/uploads/2016/01/The- 16 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Evolution-of-Mammalian-Sound-Localization.pdf Auditory masking
. The masking effect by a masking tone and the new masking threshold:
17 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Auditory masking
. New hearing threshold because of masking tone:
. Temporal masking: © Fastl, Zwicker: “Psychoacoustics”
© Fastl, Zwicker: “Psychoacoustics” 18 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Binaural hearing (using 2 ears) enables directional hearing – localization of sound sources in a 3D space with a certain precision
© Blauert: “Communication Acoustics”
19 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Sound localization requires some mechanisms: . interaural time difference (ITD) – mechanism that functions up to 2000 Hz . interaural level difference (ILD) – mechanism that functions from 500 Hz . dynamic localization by head movement – improves the precision of sound source localization . head related transfer functions (HRTF) – mechanism that enables sound localization in the median plane . auditory scene analysis – includes higher brain functions for sound source recognition and analysis
20 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Interaural time and level difference overview
21 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. ITD can go up to 0,6 ms for the average person . ILD depend on the difference level (because of the JND – Just Noticeable Difference)
© Psychology course; http://www.appstate.edu/~steelekm/classes/psy3203/topics_F05.htm
22 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Localization precision as function of sound source azimuth and its frequency
23 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Cone of confusion – places with same ITD and ILD . Solution – dynamic localization by head movement (functions for signals longer then 1 s)
© http://gyronymo.free.fr/audio3D/the_experimenter_corner.html
24 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Since the head is not round, and the torso also reflects sound . The sound signal recorded at the left and right ear will be significantly different even on the cone of confusion (HRTF!) . This effect is highly frequency dependent
25 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests © http://gyronymo.free.fr/audio3D/the_experimenter_corner.html Binaural hearing
. HRTF – the reason why we are able to localize sounds in the median plane
26 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Measurements of individual HRTF’s
27 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. HRTF differences for 2 persons, same direction
28 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. HRTF difference for same person (3 measurements), different directions . Localization is better for broadband sound . This is especially true above 6 kHz where HRTF’s have greatest differences
29 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. HRTF’s and learned (from own listening experience) . If a narrowband noise signal is played anywhere from the medial plane, the sound direction seems to change with the change of the source frequency . Several seconds of learning process
30 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Auditory scene analysis
31 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. auditory scene analysis
32 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Auditory system computer models - signal driven process (bottom-up)
© J. Blauert, Communication Acoustics 33 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing
. Experiment for 2 simultaneous speech source in a real room
34 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Hearing and space
© http://gyronymo.free.fr/audio3D/the_experimenter_corner.html
35 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Precedence effect
. Primary effect for understanding the creation of phantom sources; the other is amplitude panning
sine signal
L 50ms L 5ms L 1ms C R 1ms R 5ms R 50ms
36 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Amplitude panning
. The phantom image is moved by different intensities emitted by 2 or more coherent sound sources
sin g g i 1 2 sin0 g1 g2
37 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Amplitude panning
. Why the perceived source is called “phantom source”?
38 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Trade-off (Haas effect)
. Interaction between interaural time & intensity differences
39 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Spaciousness
. The influence of only one direct + one reflected sound wave
40 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Franssen effect
. But…
41 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
42 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Principles of psychoacoustics
. Psychoacoustics - science of sound perception . It investigates statistical relationships between acoustic stimuli and hearing sensations . Psychoacoustic models mimic the hearing mechanism . A good understanding of the sensory response of the human auditory system (HAS) is essential to the development of psychoacoustic models … where the perceptual quality of processed audio must be preserved to the greatest extent. (Y. Lin, W. H. Abdulla. “Audio Waterk”, Ch. 2 - Principles of Psychoacoustics, Springer 2015)
43 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Auditory tests and psychoac. measurements
. Sound stimuli often used in psychoacoustic tests
© Fastl, Zwicker: “Psychoacoustics”, pp. 2 44 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Loudness = intensity sensation . besides loudness of singular sound events, the loudness of partially masked sounds is often perceived as well (referent sound + masking sound simultaneously) . JND (just noticeable difference) of loudness is around 1 dB
© Fastl, Zwicker: “Psychoacoustics”, pp. 218 45 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Loudness level in phones = dB @ 1 kHz 100 315 1000 4000 16000
46 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests © Gelfand, Hearing, pp. 208 Loudness
. Phone curves
© Brüel & Kjaer, Fundamental of measuring Sound, 2007 47 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. A-weighting filter (A-level, dBA)
48 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
0 dB HL
49 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests 0 phone Loudness
. Hearing loss categories
50 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Cochlear implant for patients that still have the auditory nerve working
51 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Typical loss of hearing sensitivity with age
© Fastl, Zwicker: “Psychoacoustics”, pp. 21
52 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Relation between SPL increase and hearing sensation
53 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Sone is a unit of loudness that relates to how loud a sound is perceived . Sone scale is linear . Doubling the perceived loudness doubles the sone value!
© Gelfand, Hearing, pp. 209
Loudness of 40 phon (LN) equals loudness of 1 sone (N), for loudness above 40 phon or 1 sone!
54 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Loudness
. Example of loudness calculation procedure using a charts indicating measured third-octave band levels of a factory noise . Loudness war!
© Fastl, Zwicker: “Psychoacoustics”, pp. 234 55 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Pitch
. Pitch = frequency sensation 50 Hz -> jnd = 3 Hz 150Hz -> jnd = 2 Hz . Double pitch is perceived as an octave 1000 Hz -> jnd = 4 Hz (double or half frequency of a referent 3000 Hz -> jnd = 18 Hz sound), but not above 1 kHz 10000 Hz -> jnd = 90 Hz
56 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Pitch
. The pitch of a complex tone doesn’t change with taking away the fundamental of the tone . It is only perceived as a change in timbre (orchestras with different instruments) . Pitch perception depends on frequency, duration, intensity…
© Gelfand, Hearing, pp. 225 57 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Pitch
. Different instruments have different levels of harmonics, but they still retain the same pitch . A good example here
58 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Sharpness
. Sharpness is linked to the spectral characteristics of the sound . A high-frequency signal has a high value of sharpness (thus, sharpness is usually inverse to sensory pleasantness) . This metric is measured in acum . Sharpness of one acum is produced by a band of noise one- critical band wide centered on 1 kHz having a level of 60 dB
59 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Sharpness
. The value of g(z) is unity for critical band rate from 0 to 16 Bark, and rises to a value of 4.0 by the time 24 Bark is reached
60 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Sharpness
. Sharpness is linked to the spectral characteristics of the sound . Sharpness can be a useful measure where the high frequency content of a sound is important to a product's quality
61 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Roughness
. It describes the human perception of temporal variations of sounds . This metric is measured in asper . One asper is defined as the roughness produced by a 1000Hz tone of 60dB which is 100% amplitude modulated at 70Hz
62 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Roughness
. If a tone (e.g. 1 kHz sine) is 100% amplitude modulated, our sensation depend on the modulation frequency . The first sensation experienced is fluctuation strength, where the individual loudness modulations are audible . This experience peaks at 4 Hz . Once the modulation frequency reaches 15 Hz, the sensation of roughness begins to appear
rough sounds not rough sounds
63 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Fluctuation strength
. Fluctuation strength is similar to roughness except it quantifies subjective perception of slower (up to 20Hz) amplitude modulation of a sound . Generally, fluctuation strength is perceived as an irritating property (alarm sounds!) . Fluctuation strength of one vacil is defined by a 60 dB 1 kHz tone 100% amplitude modulated at 4 Hz
fluctuating sounds not fluctuating sounds
64 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Combined psychoacoustics quantities
. Many times, different combined psychoacoustic quantities are needed to set a formula for expressing: . sound quality of a certain product . “noise” quality and noise annoyance . soundscape quality, expectancy, acceptability . Often, the percentile of loudness is another useful metrics, such as N5, N50, N95 (for example N5 is loudness value just exceeded for 5% of the measurement period)
65 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
66 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Sound quality is a descriptor of the adequacy of the sound attached to a product (Jens Blauert)
67 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Psychophysics – science of measuring human perception
. Steven’s power law is a general relation between the physical strength of a stimulus and the subjective perception of that stimulus (valid for all senses)
Psychophysical function:
L = k Ie
L = perceived intensity k = person dependent constant I = physical intensity e = constant, depending on the sense
68 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Weber’s law – statement about the JND (just noticeable difference) of the perceived quantity I = k I . ∆I = smallest detectable change in perception (just noticable difference – JND) k = constant I = physical intensity
69 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Finding a threshold in the threshold test (50%, 75%):
70 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. First, we made a statement, a hypothesis that gives information on the design of the experiment. There are 2 hypothesis types: . Research hypothesis - verbal expression of the experimental test . Statistical hypothesis - restatement of the research hypothesis to allow hypothesis testing . In a research hypothesis (e.g. higher noise barrier decreases the perceived noise loudness at the imission point), there are 2 types of variables: . Independent variable (barrier height, objectively measurable) . Dependent variable (subjective rating of the sensation of noise level)
71 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Statistical hypothesis (one or more) is an expression of the research hypothesis to allow testing . First, the null hypothesis is formed (e.g., the barrier height has no effect on the perceived noise level) . Then, the alternative hypothesis is formed (the independent variable has an effect on the dependent variable) . Finally, the decision rule is formed in order to determine if the effect is due to chance Typically, p = 0.05 (1/20) chance of making an error is acceptable for “rejecting the null hypothesis”
72 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Variables can be: 1. Quantitative . interval or ratio . parametric statistics can be applied . data follows ‘bell curve’ distributions, and center and width of the curve are of interest 2. Qualitative (nominal or ordinal) . non-parametric statistical techniques are applied . data represents number of scores within each category
73 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Measurement types (according to T. Poulsen): 1. Threshold test . To find out when a signal is just audible, just different from another etc. 2. Balance test . To find out when a signal gives the same subjective experience as another signal (e.g. a reference signal). It could be in relation to loudness, pitch, duration, etc. 3. Scaling test . The test signal is evaluated in relation to a scale, e.g., ’weak- medium-loud’, the numbers from 1 to 10, etc. 4. Task test . The test subject perform a given task in accordance with a given instruction. E.g. press a button when a certain situation occurs, repeat words transmitted through a transmission channel, solve calculation tasks, etc.
74 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Psychoacoustic tests
. Measurement methods: 1. Classical psychometric methods . Method of limits (descending, ascending, bracketing) . Method of adjustment . Method of constant stimuli 2. Method for eliminating subject bias: . Classical solution - use of “Catch trials” (presentations without stimuli) . Modern solution - criteria free procedures (unbiased), forced- choice procedures , n-Interval Forced Choice (n-IFC) or Alternative Forced Choice (AFC) methods 3. Adaptive methods: . When trials do not give valuable information (if far away from the threshold which you are interested it). You have to have a qualified guess where the threshold is before using the methods.
75 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Scales
. We need a metric (a measurement system) for evaluating sounds! . Scales can generally fall into 4 categories: nominal scale, ordinal scale, interval scale and ratio scale . Scales can be a good graphical aid. 1. Graphical (continuous) scales – any value can be chosen from a continuous bar; there are only labels indicating the transition between 2 different descriptors 2. Categorical (discrete) scales – the values are discrete, only discrete values can be chosen during the test (e.g. Likert scale with odd number of categories: 5, 7, 9, 11…) . Question: Do scales with the equidistantly distributed quality labels have perceptually equal-interval properties? . This is a question of what a certain adjective means in a certain language (question of semantic differences)! 76 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Differences in scaling and labels
77 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests © Zielinski et al., 2007 Graphical scales in listening tests
. Two type of graphical scales: 1. Continuous impairment scale – typically for comparing evaluation of impairments exhibited my processed sound stimuli compared to unimpaired reference stimuli (recommended by ITU-R BS.1116 standard) 2. Continuous quality scale – instead of impairment, labels of quality are given, and they do not define discrete points, but rather intervals (recommended by ITU-R BS.1534 standard)
© Zielinski et al., 2007 78 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests An example of using scales
© Zielinski et al., 2007
79 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
80 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests M. Horvat, K. Jambrošić, H. Domitrović, Influence of Short Term Noise on Concentration and Human Performance // NAG/DAGA 2009 International Example 1 Conference on Acoustics, 2009. 78-80
. Influence of Short Term Noise on Concentration and Human Performance . Four groups of test subjects were exposed to a specific type of noise: . sinusoidal signal at 1 kHz . pink noise signal . narrow band noise centered at 1 kHz . 1 kHz sinusoidal carrier signal 100 % amplitude modulated with a 1 Hz sine . The reference test was made in quiet for each group + in noise at 8, 16, 32 and 64 sone
81 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 1
. Some results:
82 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 1
. Humans can maintain concentration required for performing a given task when exposed to noise for a short period of time . The increase of negative emotions like queasiness, tension and irritation is observed
83 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests M. Horvat, H. Domitrović, K. Jambrošić, Sound Quality Evaluation of Hand- Held Power Tools. // Acta acustica united with acustica. 98 (2012) , 3; Example 2 487-504
. Sound Quality Evaluation of Hand-Held Power Tools . Power drills, hand-held circular saws and jigsaws have been chosen, recorded in idle working state and switch off phase . Examples of category scaling and semantic differential used:
. Sound categories: loud, sharp, rough, stable, clean, trembling, muffled, crackling, rustling, clear, buzzing, harsh, howling and whistling . Perception categories: unpleasant, beautiful, frightening, powerful, alarming, attractive, monotonous, repulsive and tense
84 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 2
. Jigsaw electric tool sounds
Idling stage: Stopping stage:
85 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 2
. Ultimate goal of this and many other studies of sound quality:
86 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 3
. Sound Quality of Violins
87 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 3
1-1 1-2 1-3 1-4 1-5 1-6 1-7
Average sound quality score
1-7 1-5 1-3 1-1 1-2 1-4 1-6
88 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests K. Jambrošić, M. Horvat, H. Domitrović, Assessment of urban soundscapes with the focus on an architectural installation with musical features. // Example 4 The Journal of the Acoustical Society of America. 134 (2013) , 1; 869-879
. Assessment of urban soundscapes with the focus on an architectural installation with musical features . Urban soundscapes can be perceptually assessed by on-site surveys or laboratory tests and objectively evaluated based on monaural, binaural or multi channel recordings
Sea organ Zadar Park in Zagreb Lendkai Graz Railways station Zagreb
89 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests M. Horvat, K. Jambrošić, J. Francetić, H. Domitrović, M. Rychtarikova, V. Chmelik, On the Ability of Normal Sighted Persons to Assess Room Size Example 5 and Position Inside the Room Based on its Acoustic Response. // Akustika. 24 (2015) ; 2-8
. Self-localization - hand claps (own) of footsteps . Room size assessment - central position - hand claps (own)
90 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 5
Sound absorption Scattering
α= 0.1 Walls + ceiling s= 0.05
α= 0.2 Ceiling s= 0.9
α= 0.4 One wall s= 0.9
Loudspeaker system Headphones
91 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 5
Self localization Room size assessment
Percentage of correct answers Percentage of correct answers according to absorption - experiment 1 according to absorption - experiment 2 40 40 35 35 30 30 25 25 20 20 15 15 10 10 5 5 0 0 α 0.1 α 0.2 α 0.4 α 0.1 α 0.2 α 0.4
clap - correct steps - correct clap - correct steps - correct
92 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Klaus Genuit: “Sound Design”, Lecture at EAA Winter School, AIA-DAGA Example 6 2013, Merano
. “Evader” and similar projects – search for best alarm sounds for electric and hybrid cars that are too quite 18 Rank Pleasantness 16 Rank Recognizability
14
12
10
Rank 8
6
4
2
0 A B C D E F G H I J K L M N O P Q
93 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests M. Horvat, J. Benklewski, K. Jambrošić, H. Müllner, M. Rychtarikova, R. Exel, The Challenges in Preparing the Stimuli to be Used in Subjective Example 7 Evaluation of Impact Sound Insulation // Book of proceedings from ATF 2017, 2017. 82-91
H2020 RISE “Papabuild” project
94 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Example 7
. How to compare the loudness of static and changeable sounds
95 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Some references – Books
. J. Blauert (ed.): “Communication Acoustics”, Springer, 2005 . H. Fastl, E. Zwicker: “Psychoacoustics. Facts and Models”, Springer, 2007 . S. A. Gelfand: “Hearing. An Introduction to Psychological and Physiological Acoustics”, informa healthcare, 2010 . D. M. Howard, J. A. S. Angus: “Acoustics and Psychoacoustics”, Focal Press, 2009 . Suzuki et al: “Principles and Applications of Spatial Hearing”, World Scientific, 2011 . T. Poulsen: “Psychoacoustic Measuring Methods”, Lecture notes, Ørsted·DTU, Acoustic Technology, 2007 . Rodrigo Ordonez: “Lectures on psychoacoustics”, Workshop for COST action TU0901, 2013
96 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Some references – Journal papers
. N. Otto, S. Amman, C. Eaton, S. Lake: “Guidelines for Jury Evaluations of Automotive Sounds”, Sound and Vibration, April 2001 . S. Zielinski, P. Brooks, F. Rumsey: “Of the Use of Graphic Scales in Modern Listening Tests”, 123rd AES Convention, Paper 7176, 2007 . S. Zielinski, F. Rumsey: “On same Biases Encountered in Modern Audio Quality Listening Tests – A Review”, JAES, Vol. 56, No. 6, 427-451, 2008 . S. Zielinski: “On same Biases Encountered in Modern Audio Quality Listening Tests (Part 2)”, JAES, Vol. 64, No. 1/2, 55-74 2016 . “New Horizons in Listening Test Design”, JAES, Vol. 52, No. 1/2, 65-73, 2004 97 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Some references – Journal papers
. Tutorial Seminar: Listening Tests in Practice, Chairman: N. Zacharov AES 115th Convention, 1330-1800, 2003 . Head Acoustics: Psychoacoustic Analyses I, Application Note 10/16 . Head Acoustics: Conducting Listening Tests, Application Note
98 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Thank you for your attention…
… hope you could hear something new!
99 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
100 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Which sound reproduction system should we use?
. Complete frequency spectra . Complete hearing dynamic range without distortion . All information about the direct sound, first reflections, diffuse field . The “sweet spot” as large as possible . Different systems have different areas of proper sound source localization
101 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural systems
. Most natural sound reproduction system, only 2 channels . Using HRTF (Head Related Transfer Functions) for auralization purposes
102 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural systems
. But, only individual reproduction possible . Non-individual HRTF’s, front-back confusion . Head tracking and real-time binaural syntehsis
103 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural systems
. In-between alternative – use of loudspeakers for binaural reproduction, with crosstalk cancellation (CTC) algorithms
104 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Stereo(phonic) systems
. Use of amplitude panning for positioning sound sources . Speaker angular distance has to be modest!
105 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Stereo(phonic) systems
. The development of cinema audio systems was the initiator of surround sound innovation
106 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Stereo(phonic) systems
. New systems with encoded height information . Object based systems! . VBAP:
107 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Coherent and homogeneous systems
. System with stable sound image also by position and head movement change; no direction is preferred by the system (unlike home cinema) . Acoustic holography – recreation of the sound field . Ambisonics and Wave Field Synthesis (WFS) systems
108 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Ambisonics systems
. Sound field decomposition to spherical harmonics
109 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Ambisonics – Soundfield microphone
. 1st order ambisonics recording with 4 capsules . Up to 3rd order recording with Eigenmic (32 capsules)
110 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Ambisonics – encoding and decoding
. Example of sound source circling in the horizontal plane within the ambisonics system
© http://gyronymo.free.fr/audio3D/the_experimenter_corner.html
111 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Ambisonics
112 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Wave field synthesis
. Based on Huyghens' principle - propagation of a wave can be formulated by adding the contributions of all of the secondary sources positioned along a wave front
113 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Wave field synthesis
114 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Virtual reality systems
. CAVE = Computer Aided Virtual Envirnoment . Visual 3D space (goggles), Audio 3D space usually rendered using HRTF (Head Related Transfer Functions)
115 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Comparison of sound reproduction systems
limitations mono stereo 5.1 Ambisonics WFS binaural azimuth 0° -30°... 30° 360° lim. 360° 360° 360° elevation no no simulated yes no for 2D yes head movement yes limited limited yes yes no source close to head no no no yes yes yes distance no simulated limited yes yes yes spacial impression no simulated limited yes yes yes sound envelopment no no limited yes yes yes
116 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests . Overview of the hearing process . Sound reproduction systems . Acoustic comfort . Psychoacoustics and psychoacoustic parameters . Listening tests . Examples (case studies)
117 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Acoustic comfort
RT ~ 1 s STI ~ 0.55 RT ~ 3 s STI ~ 0.40 ? C80... G… Leq… C80... G… Leq… ? ? ? ? ? ?
118 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Acoustic comfort
119 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Acoustic comfort
Noise levels
Speech Acoustic Sound intelligibility comfort insulation
Reverberance/ spaciossness
120 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Acoustic defects
> 17 m
121 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Auralization – standpoint importance!
122 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Summary ≠ ≠
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123 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests