1、 1 Scope This guideline specifies the audio recording reference level for intra- and inter-studio operations concerned with motion-picture post-production audio recording on both sprocketed and nonsprocketed analog and digital magnetic and photographic materials. 2 Normative reference The following
2、document contains provisions which, through reference in this text, constitutes provisions of this guideline. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this guideline are encouraged to investigate the possib
3、ility of applying the most recent edition of the document indicated below. SMPTE RP 155-2004, Motion Picture and Television Reference Level for Digital Audio Systems 3 Specifications 3.1 The audio recording reference level shall be a sine wave of approximately 1 kHz. 3.2 For analog recording on magn
4、etic materials, the fluxivity of the reference level shall be 185 nWb/m. 3.3 For analog recording on photographic audio tracks, the reference level shall correspond to 50% maximum modulation. The maximum modulation width is 0.076 in (1.93 mm) for 35-mm monophonic sound tracks, 0.033 in (0.84 mm) for
5、 each track of 35-mm stereo sound tracks, and 0.060 in (1.52 mm) for 16-mm monophonic sound tracks. The condition of 100% modulation is commonly referred to as optical clash, and thus 50% modulation represents a level of approximately 6 dB below optical clash (see figure 1). 3.4 For digital recordin
6、g, the reference level shall correspond to 20 dB below the maximum recording level of the digital medium. Page 1 of 3 pages EG 9-2005Revision of EG 9-1995SMPTE ENGINEERING GUIDELINE Audio Recording Reference Level for Post-Production of Motion-Picture Related Materials Copyright 2005 by THE SOCIETY
7、OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 (914) 761-1100 Approved May 4, 2005 EG 9-2005 Page 2 of 3 pages 100% x WDCBA 100% x WBA MOD %+=+= WHERE: W = 0.076 IN (1.93 MM) FOR 35-MM MONO (SMPTE 40) W = 0.033 IN (0.84 MM) FOR 1 TRACK OF 35-MM STEREO (SMPTE
8、 203) W = 0.060 IN (1.52 MM) FOR 16-MM MONO (SMPTE 41) EXAMPLE: % MODULATION OF ONE TRACK OF A STEREO TRACK MOD 50% 100% x 0.0330.00820.0083MOD % IN 0.0083 A IN 0.0082 B=+=Figure 1 Measurement of percent modulation EG 9-2005 Page 3 of 3 pages Annex A (informative) Additional information A.1 The spec
9、ified level shall normally correspond to 0 on a VU meter, specified in IEC 60268-17, which normally corresponds to 4 on a peak program meter having a scale of 0 to 7 in accordance with IEC 60268-10. This refers to type 2A program level meters. Type 2B program meters will read test for the specified
10、level. A.2 The reference level specified in 2.1 and 2.2 is available on the following SMPTE test films: Magnetic M35-SL and M16-SL; Photographic P35-SL and P16-SL. A.3 The dimensions for optical clash in 2.3 are determined from SMPTE 40 for 35-mm and SMPTE 41 for 16-mm film. Annex B (informative) Bi
11、bliography SMPTE 40-2002, Motion-Picture Film (35-mm) Photographic Audio Records - Release Prints SMPTE 41-2004, Motion-Picture Film (16-mm) Prints Photographic Audio Records SMPTE 203-2003, Motion-Picture Film (35-mm) Prints Two-Track Photographic Audio Records IEC 60268-10 (1991-03), Sound System Equipment Part 10: Peak Programme Level Meters IEC 60268-17 (1990-10), Sound System Equipment Part 17: Standard Volume Indicators
