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Ref. No. : ISO/R 389-1964/Add.l-1970 (E)
IS0
FOR STA N DARD I Z AT I O N
I NT ERN AT I ON AL ORGAN I2 AT I ON
ADDENDUM 1
TO
IS0
.
R E CO M M E N DATI O N
R 389-1964
STANDARD REFERENCE ZERO
FOR THE CALIBRATION OF PURE-TONE AUDIOMETERS
ADDITIONAL DATA
WITH THE 9-A COUPLER
IN CONJUNCTION
1st EDITION
October 1970
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
F’rinted in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The Addendum 1, Additional data in conjunction with the 9-A coupler, to IS0 Recommendation R389-1964
Standard reference zero for the calibration of pure-tone audiometers, was established by Technical Committee
ISO/TC 43, Acousrics, the Secretariat of which is held by the British Standards Institution (BSI).
This Addendum was the subject of Draft IS0 Recommendation No. 1712, which was submitted to all IS0 Member
-
Bodies for enquiry in October 1968. It was approved, subject to a few modifications of an editorial nature, by the
following Member Bodies :
Australia India South Africa, Rep. of
Austria Iran Spain
Belgium Israel Sweden
Brazil Italy Switzerland
Thailand
Canada Japan
Czechoslovakia Korea, Rep. of Turkey
Finland Netherlands U.A.R.
France New Zealand United Kingdom
Germany Norway U.S.S.R.
Greece Poland
The following Member Bodies opposed the approval of the Draft
Denmark
U.S.A.
This Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council, which decided
to accept it as ADDENDUM 1 to IS0 Recommendation R 389- 1964.
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FOREWORD
IS0 Recommendation R 389- 1964, Standard reference zero for the calibration of pure-tone audiometers.
expresses this reference zero in terms of earphone-coupler combinations that are national standards in various
countries. in the case of audiometers fitted with earphones of other patterns it is suggested in Appendix A-?.?
that the corresponding reference levels be obtained by an “equal loudness” balance with one of the patterns
considered in the IS0 Recommendation. in certain cases the results of such comparisons are already available.
.--
This Addendum to IS0 Recommendation R 389- 1964 is based on an assessment of the information available
from the various standardizing laboratories responsible for audiometric standards and from scientific publications
up to the end of June 1966. Some notes on the derivation of the reference levels are given in Appendix A (Addendum).
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-5- ISO/R 389- 1964/Add.l-1970 (E)
Addendum 1 to IS0 Recommendation R 389-1964 October 1970
STANDARD REFERENCE ZERO
FOR THE CALIBRATION OF PURE-TONE AUDIOMETERS
ADDITIONAL DATA
IN CONJUNCTION WITH THE 9-A COUPLER
c
1. SCOPE
This Addendum to IS0 Recommendation R 389- 1964 gives the corresponding reference equivalent threshold
sound pressure levels for eleven audiometric earphones referred to a single type of coupler, namely, the National
Bureau of Standards, Washington, USA, Type 9-A Coupler. Of these
...