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DENORMS TRAINING SCHOOL 3 “Experimental techniques for acoustic porous materials and ” 4 – 6 December 2017, Le Mans

Introduction to and psychoacoustic tests Assoc. Prof. Kristian Jambrošić, PhD

[email protected] University of Zagreb, Croatia Faculty of Electrical and Computing Motivation

Physics is just something we measure. Reality is what we perceive.

2 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Contents

. Overview of the process . 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

. Our of hearing = ear + auditory center in the . 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 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 . . Sound move through the ossicles to the like a system of leavers. . Sound vibrations cause the 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 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 .

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 selectivity of the Cochlea

© Fastl, Zwicker: “Psychoacoustics”

10 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Neural response of the auditory nerve

. The () of the perceived sound is coded in auditory nerve firing impulses . Higher amplitude is coded with higher firing !

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 we COULD hear? . – movement of the air , 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 :

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 ) enables directional hearing – localization of sound sources in a 3D space with a certain precision

© Blauert: “

19 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests Binaural hearing

. requires some mechanisms: . interaural 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)

© 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 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 ) . 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 of 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

. 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 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

. Primary effect for the creation of phantom sources; the other is amplitude panning

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 sin0 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

. 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 - of sound . 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 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 = 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- (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

. 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

. 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 (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- band levels of a factory noise . !

© 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 (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 , 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 of noise one- 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 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 frequency . The first sensation experienced is fluctuation strength, where the individual loudness 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) 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 , different combined psychoacoustic quantities are needed to a formula for expressing: . of a certain product . “noise” quality and noise annoyance . 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

. – science of measuring human perception

. Steven’s law is a general relation between the physical strength of a stimulus and the subjective perception of that stimulus (valid for all )

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 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 (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 . 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 . 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 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 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

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

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 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 , 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

… 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 without . All information about the direct sound, first reflections, diffuse field . The “sweet spot” as large as possible . Different systems have different 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 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 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

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 – 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 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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Odeon©1985-2013 Licensed to: Unversity of Zagreb, Croatia

123 DENORMS TRAINING SCHOOL - Psychoacoustics and psychoacoustic tests