9 962500 E6T5h 7831-86 F.3509 (Iso 7831 International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAR OPIAHM3AUMH HO CTAHAAPTW3AMWORGANISATION INTERNATIONALE DE NORMALISATION Cinematography - A-chain frequency response for reproduction of 35 mm photographic sound Reproduction characteristics Cinematographie - Reponse en frequence de la reproduction du son des films photographiques de 35 mm. - Chaine A - Caracteristiques de reproduction First edition - 1986-06-15 UDC 778.534.427 Ref. No. 1SO 7831-1986 (E) O 7831-1986 (E) Descriptors : cinematography, motion-picture film, motion-picture film 35 mm, sound reproduction, characteristics, frequency responses. Copyright International Organization for Standardization Price based on 4 pages 4851903 0057981 8 7831-86 Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmentai, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IsO Council. They are approved in accordance with IsO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7831 was prepared by Technical Committee ISO/TC 36, Cinematography. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. @ International Organization for Standardization, 1986 Printed in Switzerland Copyright International Organization for Standardization Not for Resale 7831-86 2962500 E06T5h ISO 7831-1986 (E) INTERNATIONAL STANDARD Cinematography - A-chain freguency response for reproduction of 35 mm photographic sound -- Reproduction characteristics Scope and field of application 3.5A-chain (transducer system): The "A" part of a motion-picture sound system (see figure 1), which extends This International Standard specifies the A-chain electrical from the transducer to the input terminals of the main fader. frequency response characteristic for photographic sound NOTE -- It is customary for the A-chain to contain the necessary de- reproduction in motion-picture control rooms and indoor emphasis network for the replay of type 1 sound tracks. In some theatres. It is intended, in conjunction with iso 2969, to assist theatres part of the de-emphasis characteristic may result from aper in the standardization of recording monitor and reproduction ture loss. Type 3 sound tracks do not require use of a de-emphasis net- characteristics of motion-picture sound dubbing theatres, work and aperture loss will normally require the use of noise reduction review rooms and indoor theatres. This International Standard decoding circuitry. covers that part.of the motion-picture sound system from the transducer to the input terminals of the main fader. B-chain (final chain) : The "B" part of a motion-picture 3.6 reproduction system (see figure 1), which extends from the 2 References input terminals of the main fader to the listening area of the room or auditorium. Iso. 2969, Cinematography -- Electro-acoustic response of motion-picture control rooms and indoor theatres Specifica- - Two B-chain characteristics are described in ISO 2969, iden- NOTE - tions and measurements. tified as curves N'and X. ISO6025, Cinematography Photographic-monophonic sound test films - Specifications. Method of measurement 4 The electrical'response shall be measured across the fader input 3 Definitions terminals or at an