ISO INTERNATIONAL STANDARD 9568 First edition 1993-01-15 Cinematography -- Background acoustic noise levels in theatres, review rooms and dubbing rooms Cinématographie -- Niveaux de bruit de fond dans les salles de projection, de visionnement et les auditoriums de doublage Reference number ISO9568:1993(E) Copyright Intermational Organization for Standardization rovided by IHS cense with 1 rmitted without license from IHS Not for Resale ISO9568:1993(E) Foreword Iso (the International Organization for Standardization) is a worldwide of preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for represented on that committee.International organizations, governmental and non-governmentai, in liaison with IsO, also take part in the work. IsO (lEC)onallmattersofelectrotechnicalstandardization. Draft international Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 9568 3 was prepared by Technical Committee ISO/TC 36, Cinematography. Annex A of this International Standard is for information only. @ISO1993 by any means, electronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. International Organization for Standardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland ii etworking permited without license from IHS Not for Resale INTERNATIONAL STANDARD ISO9568:1993(E) Cinematography Background acoustic noise levels in theatres, review rooms and dubbing rooms Scope IsO 266:1975,Acoustics —Preferred frequencies for measurements. This International Standard specifies measurement IEC 651:1979, Sound level meters methods and maximum ratings for indoor background sound pressure levels in theatres, review rooms and dubbing rooms. Test conditions It applies to noise emitted by heating, ventilating and air-conditioning systems, intrusive noise from the projector(s) associated with the theatre and noise emitted by any other mechanical or electrical equip 3.1 The air-handling system of the theatre shall be ment in the theatre building. It is intended for appli- brought to the noisiest state in which it is used during cation when the background noise is essentially a screenings, generally "on", with cooling compressors steady-state sound, without strong time-varying com- operating. Any other mechanical or electrical equip- ponents. ment, such as projector exhaust fans, sump pumps, transformers, or the like, within the theatre building It does not apply to intrusive noise from other sources shall be brought to the noisiest state that will occur outside the theatre, such as aircraft, highway traffic during screenings. The projector system shall be run- or adjacent theatres, or to noise resulting from the ning normally, with film. Power to the theatre sound operation of the sound system in the theatre, or the system shall be turned off. vibration of the theatre, i.e. movement of the building below20Hz. 3.2 2 Measurement equipment shall conform to IEC 651, using a class Il octave band filter or class Il third-octave band filter in accordance with ISO 266. 2 Normative references 3.3 The measurement system shall be set to "slow" reading. The following standards contain provisions which through reference in this text, constitute provisions of this International Standard. At the time of publica- 3.4 The measurement system shall be calibrated tion,the editions indicated were valid.All standards immediately before use bymeans of an acoustic are subject to revision, and parties to agreements calibrator accurate to within ± O,5 dB for sound based on this International Standard are encouraged pressure level. The calibration shall be checked after to investigate the possibility of applying the most re use, and if changes greater