1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58ICS 17.140.01Acoustics Loudness scaling by means of categoriesBRITISH STANDARDBS ISO 16832:2006BS I
2、SO 16832:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI 2006ISBN 0 580 49591 4Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct application.Compliance with a Bri
3、tish Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 16832:2006.The UK participation in its preparation was entrusted by Technical Committee EH/1, Acoustics, to Subcommittee EH/1/1, Hearing.A list
4、of organizations represented on EH/1/1 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a INTERNATIONALSTANDARDISO16832First edition2006-08-01Reference numberISO 16832:2006(E)Acoustics Loudness scaling by means of categoriesAcou
5、stique Mesurage de la sonie par chelles de catgoriesBS ISO 16832:2006iiiiiContents Page1 Scope 12 Normative references 13 Terms and definitions 14 Category loudness scaling procedure . 25 Evaluation of the category loudness scaling 46 Test report 5Annex A (informative) Example of a reference method
6、6Annex B (informative) Sample level sequences 9Annex C (informative) Illustration of loudness scales 10Bibliography . 11BS ISO 16832:2006ivForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The work of preparing
7、 International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-governmental, in liaison
8、with ISO, also take part in the work. ISO collaborates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technica
9、l committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to th
10、e possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 16832 was prepared by Technical Committee ISO/TC 43, Acoustics.BS ISO 16832:2006vIntroductionThe assessment of loudness fun
11、ction based on category loudness scaling is used when the evaluation ofhearing is not only necessary at the boundaries of the auditory sensation area (threshold of hearing,uncomfortable level), but for a knowledge over the entire individual auditory sensation area.Important fields of use are diagnos
12、tic evaluations, especially the evaluation of recruitment and fitting of hearinginstruments.Since the results of loudness scaling can markedly depend on the exact procedure used, this InternationalStandard sets the conditions for reliable measurement methods.BS ISO 16832:2006blank1Acoustics Loudness
13、 scaling by means of categories1ScopeThis International Standard specifies basic methods for scaling loudness into categories for audiologicalapplications.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the ed
14、ition cited applies. For undated references, the latest edition of the referenced document(including any amendments) applies.ISO 8253-1:1989, Acoustics Audiometric test methods Part 1: Basic pure tone air and bone conductionthreshold audiometryISO 8253-2:1992, Acoustics Audiometric test methods Part
15、 2: Sound field audiometry with pure tone andnarrow-band test signalsIEC 60645-1:2001, Electroacoustsics Audiological equipment Part 1: Pure-tone audiometers3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1 loudnessauditory sensation in terms of
16、which sounds can be ordered on a scale extending from soft to loudNOTE Loudness depends primarily upon the sound pressure of the stimulus, but also depends upon its frequency,bandwidth, waveform and duration; see IEC 600504.3.2 categoryone of an exhaustive set of classes among which loudness sensati
17、ons can be distributed3.3 category scaleordering of a loudness sensation by means of categoriesNOTE 1 The scale should contain a middle category and an equal number of categories above and below the middlecategory.NOTE 2 Perceptively equidistant categories should be used (for an example, see Annex A
18、).3.4 category loudness scalingmethod whereby the test subject judges the loudness of a presented stimulus on a category scaleNOTE Verbal categories only describe loudness (for an example, see Annex A).BS ISO 16832:200623.5 response alternativeschoices available to the test subject in the rating sca
19、leNOTE 1 The number of response alternatives may be larger than the number of categories on the category scale.NOTE 2 If verbal categories are used, the number of response alternatives should be larger than the number of categories.3.6 presentation levelsound pressure level at which the signal is pr
20、esentedNOTE The number of presentation levels can be different from the number of categories and the number of responsealternatives.3.7 dynamic range of hearingdifference between the highest stimulus level that is judged by the category “not heard” and the lowest stimuluslevel that is judged by the
21、category “extremely loud” for a specific auditory stimulus3.8 auditory sensation fieldregion defined by the dynamic range of hearing across the audible frequency rangeNOTE Because the auditory sensation area, according to IEC 600504, is enclosed by the threshold of pain, the necessityfor the additio
22、nal definition of the auditory sensation field was seen in order to define the actual measurement range.3.9 loudness functionfunction describing the relation between the signal level and the corresponding loudness3.10 familiarizationprocess of orienting the subject with the range of possible loudnes
23、s magnitudes, the response alternatives andthe procedureNOTE Within this range, stimuli are perceived absolutely with respect to their magnitude, i.e. without any perceivedrelation, e.g. very loud or soft. The state of being familiarized may have its origin by past experience or actual presentationo
24、f the range of loudness magnitudes.4 Category loudness scaling procedure4.1 GeneralThe purpose of the category loudness scaling is to evaluate the loudness function of a test subject. Therefore,signals with different levels are presented to the test subject who shall judge the loudness on a category
25、 scale.The description of the scale can be verbal, numerical or symbolic. When verbal descriptions are used,preferably, the name of the middle category is “medium”, the names of the boundary categories are “not heard”and “extremely loud”. These categories can be transformed to a scale ranging, for e
26、xample, from 0 to 50. In thiscase, “0” on the scale corresponds to “not heard”, “25” corresponds to “medium” and “50” corresponds to“extremely loud” (see Annex A).BS ISO 16832:200634.2 Procedure for assessment4.2.1 Preparation and instruction of test subjectIn the preparation and instruction of test
27、 subjects the requirements given in ISO 8253-1:1989, 5.1 and 5.2 apply.For other conditions for the audiometric tests, follow the procedures given in ISO 8253-1:1989, Clause 4, asapplicable.NOTE An example of the instruction is: “During the following examination you will hear signals (e.g. sounds, t
28、ones) thatdiffer in loudness (and pitch). Following each presentation, please indicate how loud the signal (the sound, the tone) is.”In addition, the loudness categories shall be explained. The rating scale consisting of the response alternativesshall be presented to the test subject during the test
29、. The response alternatives shall contain at least all usedverbal or numerical categories. It should have provisions to make finer judgements between verbal categories.Statistical analysis has shown that a minimum of 11 response alternatives is recommended.4.2.2 Training and familiarizationThe prepa
30、ration and instruction is followed by a training and familiarization phase, in which the test subjectshould hear levels over the whole dynamic range. This phase trains the subject and confirms the expectationsinduced by the scale (between “not heard” and “extremely loud”). This phase avoids biases c
31、aused by the firsttrials that do not cover the whole dynamic range. The phase ends when the test subject is judged to be readyfor a valid test.4.2.3 TestDuring the test, signals are presented to the test subject at all presentation levels. The range of presentationlevels should cover the individual
32、dynamic range of hearing. An estimation of the dynamic range can be derivedfrom the results of the training phase (for an example, see Annex A).After the presentation of a stimulus, the test subject shall indicate the loudness of the signal.Each test signal shall be presented at at least five levels
33、. These presentation levels shall be distinguishable andshould cover the whole dynamic range.NOTE 1 In reasonable cases, exceptions can be made. Examples are tests with children or with test subjects withextremely narrow residual dynamic range.The presentation levels should be sequenced in a non-sys
34、tematic way (pseudo-randomized). To avoid obtainingjudgements biased by the previous signal, two subsequent signals should be clearly different. These signalsshould be as different as possible without confusing the test subjects (e.g. by variation of presentation leveland/or frequency). To ensure th
35、at the test subject stays familiarized during the whole test, the dynamic range ofhearing should be covered fully during short groups of subsequent presentations.When the whole auditory sensation field is to be tested with narrow band signals, tests at at least four differentcentre frequencies are r
36、equired.NOTE 2 Preferred standard centre frequencies are , , and .4.3 Test signal characteristicsThe duration of the test signals shall be at least . However, the signal may be switched off immediately if theresponse of the test subject is “extremely loud”. The rise and fall times of the signal must
37、 comply withIEC 60645-1:2001, 8.6.3.In loudness scaling, narrow band signals shall be used. This includes filtered noise and warble tones. Thebandwidth of the signals shall not exceed one-third octave. To measure frequency-dependent effects, the filterslope of the narrow band signals shall exceed pe
38、r octave. The filter slope of the test signals limits the500 Hz 1kHz 2kHz 4kHz1s36 dBBS ISO 16832:20064application of the method. For subjects with steeply sloping hearing losses, a filter slope of at least peroctave is recommended.Whenever other signals are used, e.g. in cochlear-implant patients,
39、they shall be specified in detail.4.4 Test room and equipment4.4.1 TransducersSignal presentation may be via a loudspeaker, an earphone or, if neccessary, a cochlear implant.4.4.2 Test roomFor sound field audiometry, the ambient noise levels in the test room must comply with ISO 8253-2:1992,Clause 6
40、.Sound field conditions shall be in accordance with ISO 8253-2:1992, Clause 5.If pure tones are used in a free sound field, that sound field shall be in accordance with the specifications givenin ISO 8253-2:1992, 5.1.For signal presentation via earphone, the test room shall comply with the requireme
41、nts given inISO 8253-1:1989, 4.6.4.4.3 EquipmentThe test equipment shall comply with the general requirements given in IEC 60645-1:2001, Clause 5.5 Evaluation of the category loudness scaling5.1 Determination of reference valuesTo estimate a reference loudness function for each method, loudness scal
42、ing tests must be performed for asufficiently large group of normal hearing subjects (number of subjects ). For each response alternative,median values of the corresponding levels shall be calculated. These points reflect the form of the loudnessfunction. Then a loudness function is fitted to these
43、points giving a reference loudness function (for an example,see Clause A.6). The interquartile range of the levels used to calculate the median value is given as thereference range. The reproducibility of the test method may be checked by conducting the tests at least twotimes with a time gap of at
44、least one week with a control group of normal hearing test subjects (number ofsubjects ).5.2 Numerical and graphical presentation of the resultsThe rating scale should be transformed into a numerical scale by an appropriate monotonically increasingfunction. A 51-point scale is recommended. The relat
45、ion between the scales should be given.To provide a comparable aspect ratio in the graphical presentation of the results, the full loudness scale shouldbe the same length as that of a 50 dB-range on the level axis (for examples, see Clause A.6).The function related to loudness should be approximated
46、 with a straight line, lines or a curve that best fits themeasured data points in order to interpret the results.For the interpretation of the function related to loudness, all data points should be given. Levels should be givenas sound pressure levels in decibels. Alternatively, the results of the
47、loudness scaling can be presented asequal loudness level contours.80 dB 20 20BS ISO 16832:200656 Test reportThe test report shall contain identifying information including date of birth of the tested subject, sex, date of thetest, identification of the examiner, information about the test signals an
48、d the number and manner ofpresentations, and a description of the scale.The test report shall contain the location of the test, the type of test room, and a list of the presented signalsequence containing information about the presentation level and the responses of the test subject to therespective
49、 signal.Graphical presentations should comply with 5.2.BS ISO 16832:20066Annex A(informative)Example of a reference methodA.1 GeneralNOTE See Reference 7.In the standard loudness scaling procedure, one-third-octave narrow band noises with a duration of arepresented. After signal presentation, loudness judgement is given on the scale shown in Table A.1. The nextpresentation is given only after a judgement by the subject has been made.A.2 Description of the adaptive level adjustmentIn order to achieve a fast and reliable
