1、 1 Scope This standard specifies the position, dimensions, reproducing speed, and identity of the two-, three-, four-, or six-track magnetic audio records on 35-mm magnetic film, and one single-track record on 17.5-mm magnetic film. It also specifies the assignment of records to the various tracks o
2、n the magnetic coating on the film in relation to the direction of film travel. 2 Audio records 2.1 The lateral location and width of the magnetic audio records shall be as specified in the figures and tables. 2.2 The recordings shall be made so that the azimuth of the record is at an angle of 90 3
3、to the reference edge of the film. 2.3 The audio records shall be recorded in such a manner that they can be reproduced properly by reproducing heads whose gaps are positioned along a common plane and in line. The gap width for erase heads shall be a minimum of 10% wider than the gap width of the re
4、cord being erased. 3 Reproducing speed The recordings shall be made and clearly identified so that the audio records will reproduce properly at 96 or 120 perforations per second, corresponding to 24 or 30 frames per second, respectively. Twenty-four frames per second correspond to a linear speed of
5、18 in (457 mm) per second; 30 frames per second correspond to 22.4 in (570 mm) per second. 4 Assignment of records 4.1 The principal assignment for the two-track format (see figure 1) is for the prime audio record on track No. 1 and time code on track No. 2. 4.2 Formats of 17.5-mm usually result fro
6、m slitting 35-mm film into two equal strips; in this case, the record adjacent to the perforation shall be the No. 1 record as specified in figure 2 and table 2. This shall also be the No. 1 record if it is a single recording made for 35-mm film. 4.3 For monophonic recordings, the prime audio record
7、 shall be placed on track No. 1 for all formats. Page 1 of 5 pages SMPTE 86-2005 Revision of ANSI/SMPTE 86-1996 SMPTE STANDARD for Motion-Picture Film Magnetic Audio Records Two, Three, Four and Six Records on 35-mm and One Record on 17.5-mm Magnetic Film Copyright 2005 by THE SOCIETY OF MOTION PICT
8、URE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 (914) 761-1100 Approved July 13, 2005 SMPTE 86-2005 Page 2 of 5 pages SMPTE 86-2005 Page 3 of 5 pages Table 1 Dimensions for two magnetic audio records (as shown in figure 1) Dimensions Inches Millimeters A 0.200 + 0.004 0 5.
9、0 + 0.1 0 A10.015 + 0.004 0 3.8 + 0.1 0 B 0.339 0.002 8.6 0.05 C 0.725 0.002 18.4 0.05 Table 2 Dimensions for three magnetic audio records (as shown in figure 2) Dimensions Inches Millimeters A 0.200 + 0.004 0 5.0 + 0.1 0 B 0.339 + 0.002 8.6 + 0.05 C 0.350 0.002 8.9 0.05 D 0.700 0.002 17.8 0.05 H 1.
10、377 ref 34.97 ref Table 3 Dimensions for four magnetic audio records (as shown in figure 3) Dimensions Inches Millimeters A 0.150 + 0.004 0 3.8 + 0.1 0 B 0.314 + 0.002 7.9 + 0.05 C 0.250 0.002 6.4 0.05 D 0.500 0.002 12.8 0.05 E 0.750 0.002 19.2 0.05 H 1.377 ref 34.97 ref Table 4 Dimensions for six m
11、agnetic audio records (as shown in figure 4) Dimensions Inches Millimeters A 0.100 + 0.002 2.4 + 0.05 B 0.289 + 0.002 7.34 + 0.05 C 0.160 0.002 4.06 0.05 D 0.320 0.002 8.12 0.05 E 0.480 0.002 12.18 0.05 F 0.640 0.002 16.24 0.05 G 0.800 0.002 20.30 0.05 NOTE The metric values listed in the tables are
12、 not exact conversions and deviate from accepted practice. They are based upon the practice of those countries using the metric system. Head assemblies made to either system of dimensions will be, for all practical purposes, interchangeable. SMPTE 86-2005 Page 4 of 5 pages 4.4 For stereophonic recor
13、dings, the track assignment shall be as follows: Three-track format 1 2 3 Left Center Right Four-track format 1 2 3 4 Left Center Right (Surround) For two-track stereophonic records containing phase-related material, two adjacent tracks shall be used (preferably in the three-track format, see figure
14、 2). These shall be clearly identified on all reels and containers, giving the format and the assignment of the tracks. Head tones shall only be placed on the two tracks containing audio program. The two-track format (see figure 1) is specifically excluded for recording two-track stereophonic record
15、s. 4.5 Because of the diversity of practices applied in the use of the six-track format, track assignments shall be clearly identified with each roll of film. (All reels and containers shall indicate the format and assignment of the tracks.) 5 Supplementary records Supplementary records for recordin
16、g time and control codes and other ancillary signals shall be located as shown in figure 5 and table 5. Figure 5 Supplementary records Table 5 Dimensions of supplementary records Dimensions Inches Millimeters A 0.045 + 0.004 0 1.14 + 0.1 0 B 0.038 + 0.002 0.97 + 0.05 C 1.310 0.002 33.27 0.05 SMPTE 8
17、6-2005 Page 5 of 5 pages Annex A (informative) Additional data A.1 Record width The width of the recorded area must be measured with great care because it relates directly to the calculation of flux per unit track width. When the recording head gap is narrower than the width of the coating or stripe
18、, there is a measurement complication involving both the uncertainties in viewing the track and in determining the fringing effect. If the recording head is available, the track width is best measured indirectly by measuring the gap width and adding to this dimension twice the thickness of the test
19、record magnetic coating. This correction will usually be 0.0003 in to 0.0006 in (8 mm to 15 mm). If the recording head is unavailable, the record may be made visible by the use of a carbonyl iron suspension. Care should be taken to apply the minimum amount sufficient to make the recording visible, s
20、o that the developed image is not wider than the actual recorded area. A.2 Reproducing head gap width If precision measurements or calibrations are to be made on magnetic audio records made in accordance with this standard, reproducing head gaps of the same width or wider than the recorded track mus
21、t be used to prevent edge effects or fringing. A.3 Erase heads Erasing head gaps used to erase the records specified in this standard should be substantially wider than the record specified. A.4 Magnetic coating The dimensions of the magnetic coating are not specified, but shall be wide enough to pe
22、rmit the placement of the audio records in accordance with the appropriate formats in this standard. If the recordings are made on striped motion-picture stock, the width of the stripes shall be at least 0.010 in (0.25 mm) beyond both edges of each record. Annex B (informative) Bibliography SMPTE 139-2003, Motion-Picture Film (35-mm) Perforated KS
