DOCSLIB.ORG

(2000). Psychophysical Validation of a Proprioceptive Device by Cross-Modal Matching

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(2000). Psychophysical Validation of a Proprioceptive Device by Cross-Modal Matching ACUSTICA· acta acustica Vul. ~(\ (2000) 515 - 525 © S. Hirzel Verlag· EAA 515 Psychophysical Validation of a Proprioceptive Device by Cross-Modal Matching of Loudness Patrick Susini IRCAM-CNRS, I place Igor Stravin;;ky, F-75004 Paris, France Stephen McAdams Laboratoire de Psychologie Experiffi<~ntale(CNRS), Universite Rene Descartes, EPHE, 28 ruc Scrpente, F-75006 Paris, France and IRCAM- CNRS, I place Igor Stravinsky, F-75'J04 Paris, France Summary A large number of studies performed by S. S. Stevens, 1. C. Stevens and their collaborators have estimated the intensity of one sensory modality by way of another one related to the proprioceptive sensation of muscular force and limb position. As such, using a cross-modal matching procedure, it should be possible to associate a proprioceptive sensation with an auditory sensation (e.g. loudness, brightness, roughness) having an equivalent strcngth. A new proprioceptive cstimation devicc for the continuous unidimensional judgment of non stationary sounds has been developed, and in this paper we establish an individual calibration method and the loudness scale of stationary, I-kHz pure tones by a cross- modal matching paradigm using the new device. The loudness scale and the proprioceptive scale related to muscular force applied to a unidimcnsional joystick with forcc feedback were cvaluated independently by direct estimation techniques: ratio and magnitude production, absolute magnitude estimation. The proprioceptive function obtained is characterized by a power function with an exponent of 1.77. The results obtained with ratio scaling and cross-modal techniques are similar. Hc,wever, the set of results obtained with the cross-modal technique appear more stable and less dependent on experimental conditions. Finally, these results allow us to envisage the use of this device for different auditory assessment applications. PACS no. 43.66.Cb, 43.66.Ym 1. Introduction power law seems to be applicable without exception to any physical continuum involving a variation in sensory intensity, For sounds lasting a few seconds or considered stationary, tra- at least for values not too close to threshold where certain ditional procedures of subjective evaluation [1,21 and mea- adjustments are often necessary (ef. [Ill for loudness). The surement [31 have been used. They yield reliable and robust construction of direct scales can thus be reduced to determin- results. For example, several experiments [4,5, 6, 7, 8, 9] ing the exponent of the power function. However, the problem have been performed to evaluate the loudness of I-kHz pure with direct scaling resides in the ability of the subject to de- tones based on techniques intwduced by S. S. Stevens in tect and transmit the right ratios corresponding to his or her the I950s. The most well-known are the magnitude estima- sensations. A review of the psychophysical literature con- tion and production techniques. With these, S. S. Stevens cerning ratio-scaling techniques [11,12,13,14,15] reveals a produced the sone scale corre:;ponding to a measure of variability of the results in the subjects' judgments according perceived acoustic intensity. Several experiments performed to the type of technique, the level or the value of the reference with these direct evaluation techniques have given the power sound, the presence or absence of a reference sound, and the law relating physical to perceptual magnitudes proposed by range of stimuli presented, among other factors. S. S. Stevens S. S. Stevens [10]: [16] proposed a cross-modal matching (CMM) method for confirming the power law relation which docs not require \Ii = k<.l>", (1) the subject to make numerical judgments. The task consists in matching two sensations coming from different sensory where \)i corresponds to subjective intensity, <.I>corresponds modalities, one of which has been calibrated beforehand by to physical intensity, k is an arbitrary constant to adjust the a direct estimation method [16, 17, 18]. scale, and a is the exponent tt.at depends on the sensory The use of this CMM method with an adequate force- modality and conditions of stimulation. For example, the feedback proprioceptivel device has three main advantages. psychophysical function obtained that expresses the sensa- Firstly, as S. S. Stevens emphasized, on the basis of knowl- tion of acoustic intensity as a function of physical intensity edge concerning the function for a sensory modality, it is of a 3-kHz pure tone, corresponds to a power function with an exponent of 0.67. Experiments performed by S. S. Stevens in different sensory domains have given exponents varying 1 "Proprioception" literally means "perception of one's self" and from 0.33 (visual brightness) to 3.5 (electric shock). The is used in expcrimental psychology and sensory neuroscience to refer to the perception by an organism of stimuli relating to its own position, posture, equilibrium, or internal condition. We usc it here Reccived 6 April 1998, to refer to a combination of muscular, articulatory, and positional acceptcd 7 June 2000. cues deriving from an action on a resistive external device. ACUSTICA· acta acustica 516 Susini, McAdams: Cross-modal loudness matching Vo!. 86 (2000) possible to determine the psychophysical functions of other 2. Technical description of the proprioceptive device sensory modalities by cross-modal matching. For example, the psychophysical functions of different auditory attributes 2.1. Weight-related resistmce: device schema (loudness, roughness, sharpness) can be obtained by way of the proprioceptive function corresponding to the assessment In order to evaluate audit')fy sensation by a sensation of device. Secondly, the data in the literature reveal variabil- muscular resistance, a proprioceptive system was developed. ity, between and within methods [11, 12, 13, 14, 15] and This system acts on the selsitivity of muscles, bones, liga- among subjects, that can be reduced by determining for each ments, and joints, and provides information concerning the subject an individual matching function. It is necessary with equilibrium and position of limbs of the body in space. The this aim in mind that the assessment device be individually transmitted information and sensitivity depend on the type of calibratable as a function of different factors such as indi- effort and the movement provoked by the system. It is thus important in the choice of the device to specify what type of vidual sensitivity that varies with the stimulus range and the individual process of associating the two sensory modalities. effort is involved in the subject's task during the experiment. Thirdly, the intuitive and implicit nature of this assessment In other words, the subject must know to which gestural cat- procedure in comparison with other methods of numerical egory corresponds the required muscular effort as a function estimation or ratio estimation suggests its possible useful- of the device. The representation of the effort to be made is ness in procedures where rapid assessment is necessary. For different according to the manipulated object, and to each example, in the case of continuous judgment of nonstation- object is associated an appropriate scale of muscular effort. ary signals, it is important to use a method that transcribes For example, the scale will be different if one squeezes on rapidly, easily, and continuously the subjects' estimates. Fur- a water balloon or if one manipulates the handle of a pick- ther, it is interesting that this method can provide subjects axe. The schematic of the device we settled on is shown in with continuous information concerning their ratings by pro- Figure 1. viding force feedback. With this system, the subject has information on the eval- The aim of the present article is to test the psychophys- uation being made by force feedback and the position of arm ical reliability of CMM with a new proprioceptive device and shoulder. The \ever exerts a resistance as a function of developed for that purpose. We limit this study to determin- the angle of displacement, the effect of which is to create ing the loudness function of I-kHz stationary pure tones, in a proprioceptive sensation. As such, the subject associates a order to compare our results with those of the literature and combination of muscular force and displacement with any in- to validate our device with the cross-modal matching tech- tensity variation perceived by moving the lever of a "joystick" nique. In a future article [19], this technique will be applied in the direction corresponding to the auditory sensation. For to time-varying sounds and compared with other techniques. example, to an auditory sensation for which the intensity is The proprioceptive evaluation device developed for this work perceived as being two times greater, the subject doubles the is presented in section 2. In the first series of experiments proprioceptive sensation. In this way, the result related to (section 3), w~ determine the loudness scale with ratio and an intensity sensation does not depend on the ability of the magnitude production, as well as with magnitude estimation. listener to estimate the numerical magnitude related to the To obtain greater precision, we have used different methods sensation, which involves a sensory-to-conceptual matching to examine the biases due to each one. Similarly, we have process, but rather to match one sensory magnitude to an- repeated these tests with different levels and values for the other. The data obtained allow us to establish a relation be- reference sound in order to observe their influence on the tween the muscular force in Newtons and the sound pressure evaluation. We then determine the psychophysical function level in dB SPL. related to proprioceptive sensation with the ratio production The displacement of the I~veris recorded with the help of a method, on the one hand, and with magnitude estimation, 10 kD potentiometer mount~d in the axis of the lever motion. on the other hand.
Load more

Recommended publications
  • Ebm-Papst Mulfingen Gmbh & Co. KG Postfach 1161 D-74671 Mulfingen
    ebm-papst Mulfingen GmbH & Co. KG Postfach 1161 D-74671 Mulfingen Internet: www.ebmpapst.com E-mail: [email protected] Editorial contact: Katrin Lindner, e-mail: [email protected] Phone: +49 7938 81-7006, Fax: +49 7938 81-665 Focus on psychoacoustics How is a fan supposed to sound? Our sense of hearing works constantly and without respite, so our ears receive noises 24 hours a day. About 15,000 hair cells in the inner ear catch the waves from every sound, convert them to signals and relay the signals to the brain, where they are processed. This is the realm of psychoacoustics, a branch of psychophysics. It is concerned with describing personal sound perception in relation to measurable noise levels, i.e. it aims to define why we perceive noises as pleasant or unpleasant. Responsible manufacturers take the results of relevant research into account when developing fans. When we feel negatively affected by a sound, for example when it disturbs us, we call it noise pollution. Whether this is the case depends on many factors (Fig. 1). Among other things, our current situation plays a role, as do the volume and kind of sound. The same is true of fans, which need to fulfill different requirements depending on where they are used. For example, if they are used on a heat exchanger in a cold storage facility where people spend little time, low volume or pleasant sound is not an issue. But ventilation and air conditioning units in living and working areas have to meet much different expectations.
    [Show full text]
  • Decibels, Phons, and Sones
    Decibels, Phons, and Sones The rate at which sound energy reaches a Table 1: deciBel Ratings of Several Sounds given cross-sectional area is known as the Sound Source Intensity deciBel sound intensity. There is an abnormally Weakest Sound Heard 1 x 10-12 W/m2 0.0 large range of intensities over which Rustling Leaves 1 x 10-11 W/m2 10.0 humans can hear. Given the large range, it Quiet Library 1 x 10-9 W/m2 30.0 is common to express the sound intensity Average Home 1 x 10-7 W/m2 50.0 using a logarithmic scale known as the Normal Conversation 1 x 10-6 W/m2 60.0 decibel scale. By measuring the intensity -4 2 level of a given sound with a meter, the Phone Dial Tone 1 x 10 W/m 80.0 -3 2 deciBel rating can be determined. Truck Traffic 1 x 10 W/m 90.0 Intensity values and decibel ratings for Chainsaw, 1 m away 1 x 10-1 W/m2 110.0 several sound sources listed in Table 1. The decibel scale and the intensity values it is based on is an objective measure of a sound. While intensities and deciBels (dB) are measurable, the loudness of a sound is subjective. Sound loudness varies from person to person. Furthermore, sounds with equal intensities but different frequencies are perceived by the same person to have unequal loudness. For instance, a 60 dB sound with a frequency of 1000 Hz sounds louder than a 60 dB sound with a frequency of 500 Hz.
    [Show full text]
  • Guide for the Use of the International System of Units (SI)
    Guide for the Use of the International System of Units (SI) m kg s cd SI mol K A NIST Special Publication 811 2008 Edition Ambler Thompson and Barry N. Taylor NIST Special Publication 811 2008 Edition Guide for the Use of the International System of Units (SI) Ambler Thompson Technology Services and Barry N. Taylor Physics Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 (Supersedes NIST Special Publication 811, 1995 Edition, April 1995) March 2008 U.S. Department of Commerce Carlos M. Gutierrez, Secretary National Institute of Standards and Technology James M. Turner, Acting Director National Institute of Standards and Technology Special Publication 811, 2008 Edition (Supersedes NIST Special Publication 811, April 1995 Edition) Natl. Inst. Stand. Technol. Spec. Publ. 811, 2008 Ed., 85 pages (March 2008; 2nd printing November 2008) CODEN: NSPUE3 Note on 2nd printing: This 2nd printing dated November 2008 of NIST SP811 corrects a number of minor typographical errors present in the 1st printing dated March 2008. Guide for the Use of the International System of Units (SI) Preface The International System of Units, universally abbreviated SI (from the French Le Système International d’Unités), is the modern metric system of measurement. Long the dominant measurement system used in science, the SI is becoming the dominant measurement system used in international commerce. The Omnibus Trade and Competitiveness Act of August 1988 [Public Law (PL) 100-418] changed the name of the National Bureau of Standards (NBS) to the National Institute of Standards and Technology (NIST) and gave to NIST the added task of helping U.S.
    [Show full text]
  • Psychoacoustics and Its Benefit for the Soundscape
    ACTA ACUSTICA UNITED WITH ACUSTICA Vol. 92 (2006) 1 – 1 Psychoacoustics and its Benefit for the Soundscape Approach Klaus Genuit, André Fiebig HEAD acoustics GmbH, Ebertstr. 30a, 52134 Herzogenrath, Germany. [klaus.genuit][andre.fiebig]@head- acoustics.de Summary The increase of complaints about environmental noise shows the unchanged necessity of researching this subject. By only relying on sound pressure levels averaged over long time periods and by suppressing all aspects of quality, the specific acoustic properties of environmental noise situations cannot be identified. Because annoyance caused by environmental noise has a broader linkage with various acoustical properties such as frequency spectrum, duration, impulsive, tonal and low-frequency components, etc. than only with SPL [1]. In many cases these acoustical properties affect the quality of life. The human cognitive signal processing pays attention to further factors than only to the averaged intensity of the acoustical stimulus. Therefore, it appears inevitable to use further hearing-related parameters to improve the description and evaluation of environmental noise. A first step regarding the adequate description of environmental noise would be the extended application of existing measurement tools, as for example level meter with variable integration time and third octave analyzer, which offer valuable clues to disturbing patterns. Moreover, the use of psychoacoustics will allow the improved capturing of soundscape qualities. PACS no. 43.50.Qp, 43.50.Sr, 43.50.Rq 1. Introduction disturbances and unpleasantness of environmental noise, a negative feeling evoked by sound. However, annoyance is The meaning of soundscape is constantly transformed and sensitive to subjectivity, thus the social and cultural back- modified.
    [Show full text]
  • Brightness and Loudness As Functions of Stimulus Duration
    Brightness and loudness as functions of stimulus duration 1 JOSEPH C, STEVENS AND JAMES W. HALL LABORATORY OF PSYCHOPHYSICS. HARVARD UNIVERSiTY The brightness of white light and the loudness of white (1948) and by Small, Brandt, and Cox (1962) for white noise were measured by magnitude estimation for sets of noise. White noise provides a more suitable stimulus stimuli that varied in intensity and duration. Brightness and for this kind of problem than pure tones, because the loudness both grow as power functions of duration up to a intensity of a white noise (unlike tones) can be rapidly critical duration, beyond which apparent magnitude is es­ modulated without effecting a material change in the sentially independent of duration. For brightness, the critical sound spectrum. Thus a prominent click is heard at duration decreases with increasing intensity, but for loudness the onset of a tone but not at the onset of a noise. the critical duration is nearly constant at about ISO msec. How the loudness of white noise grows with intensity Loudness and brightness also grow as power functions of in­ has been the subject of several investigations (S. S. tensity. The loudness exponent is the same for all durations, Stevens, 1966a). Like brightness, the loudness of white but the brightness exponent is about half again as large for noise obeys the general psychophysical power law short durations as for long. The psychophysical power func­ proposed by S. S. Stevens (1961) tions were used to generate equal-loudness and equal-bright­ IjJ ~ k¢.8 (1) ness functions, which specify the combinations of intensity E and duration T that produce the same apparent magnitude.
    [Show full text]
  • Comparison of Loudness Calculation Procedure Results to Equal Loudness Contours
    University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 2010 Comparison of loudness calculation procedure results to equal loudness contours Jeremy Charbonneau University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Charbonneau, Jeremy, "Comparison of loudness calculation procedure results to equal loudness contours" (2010). Electronic Theses and Dissertations. 5428. https://scholar.uwindsor.ca/etd/5428 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). Under this license, works must always be attributed to the copyright holder (original author), cannot be used for any commercial purposes, and may not be altered. Any other use would require the permission of the copyright holder. Students may inquire about withdrawing their dissertation and/or thesis from this database. For additional inquiries, please contact the repository administrator via email ([email protected]) or by telephone at 519-253-3000ext. 3208. Comparison of Loudness Calculation Procedure Results to Equal Loudness Contours By Jeremy Charbonneau A Thesis Submitted to the Faculty of Graduate Studies and Research through Mechanical Engineering
    [Show full text]
  • Intensity of Sound
    01/02 Intensity - 1 INTENSITY OF SOUND The objectives of this experiment are: • To understand the concept of sound intensity and how it is measured. • To learn how to operate a Sound Level Meter APPARATUS: Radio Shack Sound Level Meter, meterstick, function generator, headphones. INTRODUCTION Sound energy is conveyed to our ears (or instruments) by means of a wave motion through some medium (gas, liquid, or solid). At any given point in the medium the energy content of the wave disturbance varies as the square of the amplitude of the wave motion. That is, if the amplitude of the oscillation is doubled the energy of the wave motion is quadrupled. The common method in gauging this energy transport is to measure the rate at which energy is passing a certain point. This concept involves sound intensity. Consider an area that is normal to the direction of the sound waves. If the area is a unit, namely one square meter, the quantity of sound energy expressed in Joules that passes through the unit area in one second defines the sound intensity. Recall the time rate of energy transfer is called "power". Thus, sound intensity is the power per square meter. The common unit of power is the watt ( 1w = 1 Joules/s). Normally, sound intensity is measured as a relative ratio to some standard intensity, Io. The response of the human ear to sound waves follows closely to a logarithmic function of the form R = k log I , where R is the response to a sound that has an intensity of I, and k is a constant of proportionality .
    [Show full text]
  • Table Chart Sound Pressure Levels Level Sound Pressure
    1/29/2011 Table chart sound pressure levels level… Deutsche Version • Decibel Table − Loudness Comparison Chart • Table of Sound Levels (dB Scale) and the corresponding Units of Sound Pressure and Sound Intensity (Examples) To get a feeling for decibels, look at the table below which gives values for the sound pressure levels of common sounds in our environment. Also shown are the corresponding sound pressures and sound intensities. From these you can see that the decibel scale gives numbers in a much more manageable range. Sound pressure levels are measured without weighting filters. The values are averaged and can differ about ±10 dB. With sound pressure is always meant the effective value (RMS) of the sound pressure, without extra announcement. The amplitude of the sound pressure means the peak value. The ear is a sound pressure receptor, or a sound pressure sensor, i.e. the ear-drums are moved by the sound pressure, a sound field quantity. It is not an energy receiver. When listening, forget the sound intensity as energy quantity. The perceived sound consists of periodic pressure fluctuations around a stationary mean (equal atmospheric pressure). This is the change of sound pressure, which is measured in pascal (Pa) ≡ 1 N/m2 ≡ 1 J / m3 ≡ 1 kg / (m·s2). Usually p is the RMS value. Table of sound levels L (loudness) and corresponding sound pressure and sound intensity Sound Sources Sound PressureSound Pressure p Sound Intensity I Examples with distance Level Lp dBSPL N/m2 = Pa W/m2 Jet aircraft, 50 m away 140 200 100 Threshold of pain
    [Show full text]
  • Sound Sense – by D. Lovegrove, S. Hough
    SOUND (QUALITY) SENSE Many of us would agree that there are a lot of things around us that are too noisy, such as the seats behind the engines on a long flight, an angry two-year-old and the volume of the music system in the car next to us at the stoplight, which shakes our seats. Sometimes, though, it’s not the loudest sounds that are the hardest to live with. It’s the intermittent hiss, or the whine perfectly pitched to set our teeth on edge. When a product or an appliance is manufactured, a vehicle, a toy, a train carriage, anything that people are going to hear or be near, it should sound “right”. Not just quiet enough to be unobjectionable - that’s necessary but not sufficient. It’s got to have that indefinable Sound of Quality, the sound you would wish your car door in closing would make. A truism of sound quality work is that a good lawnmower doesn’t sound like a good refrigerator. Companies who take this sort of thing seriously do jury testing. They may use listeners like their customers to get a better measure of public opinion, or listeners from among their engineers, to gain a better understanding of which elements of the product are making the most objectionable part of the noise. The jury ranks noises according to various rules. The 2 most successful forms of comparison are “Paired Comparison” and “Semantic Differential”. The use of a Fixed Scale (“On a scale of 1-10, how annoying is this noise?”) is generally not recommended.
    [Show full text]
  • FESI DOCUMENT A2 Basics of Acoustics
    FESI DOCUMENT A2 Basics of Acoustics September 2001, 3rd revised edition to be ordered: Thermal Insulation Contractors Association Mr. Ralph Bradley Tica House Allington Way Yarm Road Business Park Darlington DLI 4QB Tel : +44 (0) 1325 734140 direct Fax: +44 (0) 1325 466704 www.tica-acad.co.uk [email protected] Basics of Acoustics Contents A2-0 Intention .......................................................................................................................................2 A2-1 Introduction ..................................................................................................................................2 A2-2 Classification................................................................................................................................3 A2-2.1 Sound Sensation .........................................................................................................................4 A2-2.2 Infrasonic, Audible and Ultrasonic Sound ...................................................................................6 A2-2.3 Airborne, Structureborne, Waterborne Sound.............................................................................7 A2-2.4 Acoustic Insulation and Sound Attenuation.................................................................................8 A2-3 Physical, technical basics............................................................................................................8 A2-3.1 Frequency, Speed of Sound, Wavelength...................................................................................8
    [Show full text]
  • PETERSEN-THESIS-2018.Pdf (1.655Mb)
    AN INVESTIGATION OF SOUND MEASUREMENT CHANGES RESULTING FROM MODIFICATIONS TO A SEMI-REVERBERANT SOUND CHAMBER A Thesis by MICHELLE ANNE PETERSEN Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Chair of Committee, Michael B. Pate Committee Members, Harry A. Hogan Maria D. King Head of Department, Andreas A. Polycarpou December 2018 Major Subject: Mechanical Engineering Copyright 2018 Michelle Anne Petersen ABSTRACT The RELLIS Energy Efficiency Laboratory, REEL, is a research and testing facility established in 1939 and an approved testing laboratory for HVI. Testing of residential ventilation devices is one of the main applications of this laboratory. Recently, the microphones for the sound chamber were changed from free-field to diffuse. The test method and procedure for measuring sones is understood, but the effect of using a different microphone type to record sound pressure levels is not. The need to understand the effects of changing equipment in sound facilities is necessary in order to provide accurate and verifiable test results. This study investigates the change in sone ratings between free-field and diffuse microphones by using the sound facilities at REEL. A total of 96 trials for eight different residential ventilation devices was performed to record sone levels over a range of less than 0.3 to 11.5 rated sones. This analysis found that there was less than a 4% difference in sone values measured when using the different microphone types. Additionally, the change in sone ratings using different resonant sound sources (RSS) was analyzed using the same data from the 96 trials.
    [Show full text]
  • Precise and Full-Range Determination of Two-Dimensional Equal Loudness Contours
    ＩＳ－０１ Precise and Full-range Determination of Two-dimensional Equal Loudness Contours Research Coordinator: Yôiti Suzuki (Research Institute of Electrical Communication, Tohoku University: Japan) Research Team Members: Volker Mellert (Oldenburg University: Germany) Utz Richter (Physikalisch-Technische Bundesanstalt: Germany) Henrik Møller (Aalborg University: Denmark) Leif Nielsen (Danish Standards Association: Denmark) Rhona Hellman (Northeastern University: U.S.A.) Kaoru Ashihara (National Institute of Advanced Industrial Science and Technology: Japan) Kenji Ozawa (Yamanashi University: Japan) Hisashi Takeshima (Sendai National College of Technology: Japan) Duration: April, 2000 ～ March, 2003 Abstract: The equal-loudness contours describe the frequency characteristic of sensitivity of our auditory system. A set of the equal-loudness contours based on British data measured in mid-1950 was standardized as ISO 226. However, several research results reported in mid-1980 showed that the set of equal-loudness contours in ISO 226 contained a large error. We, therefore, carried out this project to determine new precise and comprehensive equal-loudness contours and to fully revise the ISO 226. New equal-loudness contours were based on the data of 12 studies, mostly from measurements by the members of this team, reported since 1983. These contours were calculated using a model based on knowledge of our auditory system. Based on the research results, draft standards of the new equal-loudness contours were made and proposed to ISO/TC 43 (Acoustics). The new standard finally was established on August 2003. 1. Introduction An equal-loudness contour is a curve that ties up sound pressure levels having equal loudness as a function of frequency. In other words, it expresses a frequency characteristic of loudness sensation.
    [Show full text]