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Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

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“Step Out From the Old to the New”

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“The Right to Information, The Right to Live”

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“Invent a New India Using Knowledge”

है”ह”ह

IS 9551-6 (2001): High Fidelity Audio Equipment and Systems: Minimum Performance Requirements, Part 6: Microphones[LITD 7: Audio, Video and Multimedia Systems and Equipment]

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IS 9551 (Part 6) :2001IEC 60581-5 (1981)

Indian Standard

HIGH FIDELITY AUDIO EQUIPMENT AND SYSTEMS:MINIMUM PERFORMANCE REQUIREMENTS

PART 6 MICROPHONES

(First Revision)

Ics 33.160.50

0 BIS 2001

BUREAU OF INDIAN STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARGNEW DELHI 110002

November 2001 Price Group 3

I

,79 .4<.

Acoustics Sectional Committee, LTD 5

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NATIONAL FOREWORD

This Indian Standard (Part 6) (First Revision) which is identical with IEC 60581-5(1981) ‘High fidelity audioequipment and systems; Minimum performance requirements — Part 5: Microphones’ issued by theInternational Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on therecommendation of Acoustics Sectional Committee and approval of the Electronics and TelecommunicationDivision Council.

This standard was first published in 1984 and was technically equivalent to IEC 60581-5(1981). This revisionhas been undertaken to completely harmonize it with the corresponding IEC Standard. It is now identical withIEC 60581-5. The text of the IEC Standard has been approved as suitable for publication as Indian Standardwithout deviations. Certain conventions are, however, not identical to those used in the Indian Standards.Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear, referring to this standard, they should be read as‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is touse a full point (.) as the decimal marker.

Only the English language text of the International Standard has been retained.

CROSS REFERENCES

In this adopted standard, reference appears to certain International Standards for which Indian Standards alsoexist. The corresponding Indian Standards which are to be substituted in their place are listed below along withtheir degree of equivalence for the editions indicated :

[international

Standard

IEC 268-4 Sound system equipment —Part 4: Microphones

IEC 268-15 Sound system equipment —Part 15: Preferred matching values for theinterconnection of sound systemcomponents

[EC 58 I-1 High fidelity audio equipmentand systems : Minimum performancerequirements — Part 1 : General

Corresponding Degree of

Indian Standard Equivalence

1S 9302 (Part 3): 1981 Characteristics and Technicallymethods of measurement for sound system Equivalentequipment: Part 3 MicrophonesIS 9302 (Part 10):1980 Characteristics and domethods of measurement for sound systemequipment: Part 10 Preferred matchingvalues for the interconnection of soundsystem componentsIS 9551 (Part 1) :2001 Specification for dohigh fidelity audio equipment andsystems: Part 1 General @rst revision)

The technical committee responsible for the preparation of this standard has reviewed the provisions of thefollowing International Standard and has decided that it is acceptable for use in conjunction with this standard :

IEC 268-11 Circular connectors for interconnection of sound system components

,@,—. —

4S 9551 ( Part 6 ): 2001IEC 60581-5 (1981)

Indian Standard

HIGH FIDELITY AUDIO EQUIPMENT AND SYSTEMS:MINIMUM PERFORMANCE REQUIREMENTS

PART 6 MICROPHONES

(First Revision)

1. Scope

This part applies to microphones, primarily intended for high quality reproducing systems forhome use.

2. Object

To lay down thepart.

3. Measuring conditions

minimum requirements for microphones falling within the scope of this

All measurements shall be made in accordance with the general measuring conditions stated inI EC Publication 581-1, Part 1: General, and with the conditions of measurement given in SectionOne of I EC Publication 268-4: Sound System Equipment, Part 4: Microphones.

4-

IS 9551 ( Part 6 ) :2001IEC 60581-5 (1981)

SECTION ONE – MINIMUM REQUIREMENTS FOR CHARACTERISTICSDIRECTLY RELATED TO THE REPRODUCING QUALITY

4. Frequency response

Introduction

The frequency response requirement is defined in two stages: a type frequency response isspecified and then the permissible deviations of the response of an individual microphone fromthat type frequency response. This is because the type frequency response may not be intended to beflat, for example a so-called soloist’s microphone.

Clauseor Characteristic Method of measurement Minimum requirement

;ub-clause

I

4.1 Frequency range According to I EC Publication From 50 Hz to 12500 Hz268-4, Clause 12

4.2 Type frequency The type jkquency response curve, stated by theresponse manufacturer,whichshallbethe meanfrequency

response of microphones of that type, shall fallwithin the masks for omnidirectional or direc-tional microphones (as appropriate) given in Fig-ures 1 and 2, page s

Note. – If the claimed frequency range is widerthan the minimum requirement of 50 Hzand 12500 Hz, the tolerance Iimits shownon the masks of Figures 1 and 2 at 50 Hzand 12500 Hz stilI apply for frequenciesoutside the minimum requirement

4.3 Frequency The frequency response curve of any individual mi-response of crophone shall correspond to the type frequencyan individual response curve within the folIowing tolerances:microphone

50 Hz-250 HZ t 3 dB250 Hz-8 000 Hz *2.5 dB

8000 Hz-12500 Hz f3dB

Over the frequency range 250 Hz-8 000 Hz, theslope of the curve shall not exceed 6 dB/octave,and for lower and higher frequencies up to thelimit frequencies specified for the frequency rangeit shall not exceed 9 dB/octave

Notes 1. – Peaks and troughs in the frequency res-ponse curve not exceeding a frequencyrange corresponding to 1/8 octave shallbe neglected with respect to the require-ments for maximum admissible slope.

2. – If the claimed frequency range is wider,than the minimum requirement of50 Hz and 12500 Hz, the tolerance off 3 dB still applies

.—

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2

IS 955 I ( pan 6 ) :2001IEC 60581-5 (1981)

!*- ._..’._

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Clauseor Characteristic Method of measurement Minimum requirement

lb-clause

5. Difference !?wrlshivity measurement according The sensitivity obtained for stereo microphones orbetween the to 1EC Publication 26g-4, Sub- microphones of the same type intended to be usedsensitivities of clauses 40.1 and 10.2.1 in stereophonic installations shall be such that themicrophones average sensitivities, corresponding to each of theosed for 1/3 octave frequency bands whose central fre-stereophony quencies lie between 250 Hz and 8000 Hz inclu-

sive, do not differ by more than 3 dB from onemicrophone to the other for the same 1/3 octavefrequency baud

,.,., .

6. Directional According to I EC Publication Omnidirectional microphonepattern j6’8-4, Sub-clause 13.1 The difference between the maximum and mini-

mum values of the expression

u (e) dB20 log,~ _u(e=o)

in I EC Publication 268-4 Sub-clause 13.1a) (7)for values of O between O and 9W shall notexceed:

2 dB below 1000 Hz

4 dB between 1000 Hz and 5000 Hz8 dB between 5000 Hz and 8000 Hz

Directional microphone

The off-axis frequency response between 250 Hz and8000 Hz shall not deviate by more than+ 4 dB from the axial response, a transfer to equal-ize the values obtained at 1000 Hz being earnedout previously

Where the response at any angle and frequency ismore than 12 dB below the axial response at thesame frequency, the deviation of the response atthat angle and frequency shall be neglected

7. Front-to-random According to I EC Publication >3 dB within the frequency range 250 Hz-sensitivity in- 268-4, Sub-clause 13.2 8000 Hz

dex (for direc-tional micrrr-phones only)

8. Overload sound According to I EC Publication For sound pressure levels up to 114 dB (ref. 20 pPa),pressure 268-4, Sub-clause 14.2 the total harmonic distortion shall not exceed 1‘h

within, the frequency range .250Hz-WOO HZ

9. Rated equivalent According to I EC Publication <26 dB (ref. 20 yPa) noise A-weightedsound pressure 268-4, Sub-clause 15.1level due toinherent noise

3

IS 9551 ( Part 6 ) :2001IEC 60581-5 (1981)

Clauseor

wsb-claust

10,

Clauseor

,ub-claus

11.

12.

Characteristic

Free-fieldsensitivity

Method of measurement Minimum requirement

IAccord@g to I EC Publication ,The sensitivities of individual microphones of a

268-4, Sub-clauses 10.1 and .pqxietennine dtypeshal lnotdiffe rbymorethm10.2.1 X-3@ from the rated sensitivity at 1 O(X)HZ

specified by the rnanufacmrer for the relevanttype

SECTION TWO – OTHER CHARACTERISTICS AND REQUIREMENTS

Characteristic

Interconnection

a) Mechanical

b) Electrical

Characteristics tobe specified

Method of measurement

—

Minimum requirement

Accordhtg to I EC Publication 268-11.

According to I EC Publication 268-15

Note. – In this publication, standard values aregiven for rated sensitivity, rated impe-dance and rated load impedance

The characteristics listed in this part are mandatosyin the manufacturer’s manual or descriptiveleaflet and technical specifications

The requirements of Clause 20 of I EC Publication268-4 should also be observed

The manufacturer shall also specify the fimction ofany switches or controls on microphone or asso-ciated equipment

4

—

+5

+1

-1

-4

IS 9551 ( Part 6 ) :2001IEC 60581-5 (1981)

50 250 1000 8000 12500

FIG. 1. – Omn i-directional microphones.

dB .

+5 ---

+1- -

–1 -> c

–4 .-

50 250 1000

FIG. 2. – Directional microphones.

Hz

8000 12500 Hz

5

Bureau of Indian Standards

BI S is a statutory institution established under the Bureau of Indian Standards Act,. 1986 to promote

harmonious development of the activities of stardardization, marking and quality certification of goods andattend ing to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publication), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issueof’ BI S Handbook’ and’ Standards: Monthly Additions’.

This Indian Standard has been developed from Dot: No. LTD5(1872).

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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