SMPTE Journal ( Volume: 86, Issue: 9, September 1977)
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Distortion-Balance Tests for Motion-Picture Soundtracks
Metadata
- Publisher
- SMPTE — White Plains, NY, USA
- Doc Type
- Journal Article
- Content Type
- Original Research
- Abbreviated Title
- J SMPTE
- Volume
- 86, No. 9, pp. 620–623
- Abstract
- Regardless of how different two soundtrack negatives are in terms of product, process or treatment, they will contain the same amount of cross-modulation distortion if they both optimize at the same density on a given print when printed on the same printer. Sound-film technicians employ this principle intuitively when they purposely distort a negative to optimize a print. The following important points are made: (1) image spread distortion increases with amplitude and frequency and causes a shift in average level; (2) negative and print distortions are opposite in phase and tend to cancel algebraically; (3) distortion-balance tests using pulsed signals (which may be prerecorded on magnetic tape) provide a practical means of optimizing sound prints; (4) percent distortion (rather than decibels) is plotted against print density for a given negative or against negative density for a given print; (5) by examining the phase of the 400-Hz distortion component, one finds whether a print from a given negative needs more exposure or less to achieve net cancellation; (6) interpolation and extrapolation are easy because the curves of percent distortion vs density constitute a family of straight parallel lines over the practical range; and (7) optimum print density can be predicted from a knowledge of percent distortion in the negative—which means that this distortion rather than the negative density is the important factor. These tests may be evaluated with a meter, oscilloscope, densitometer or even a common loudspeaker.
- Publication Date
- 1977-09-01
- DOI
10.5594/J06761- ISSN
- Print:
0036-1682 - Link
- https://doi.org/10.5594/J06761
- Author(s)
- Ralph R. Wells5841 Mantilija Ave., Van Nuys, CA 91401.
- Copyright
- © 1977 Society of Motion Picture and Television Engineers, Inc.
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Ralph R. Wells; Distortion-Balance Tests for Motion-Picture Soundtracks, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977. Available at https://doi.org/10.5594/J06761
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Ralph R. Wells; Distortion-Balance Tests for Motion-Picture Soundtracks, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977. Available at https://doi.org/10.5594/J06761
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Ralph R. Wells; Distortion-Balance Tests for Motion-Picture Soundtracks, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977. Available at https://doi.org/10.5594/J06761
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<span class="citation">Ralph R. Wells; <cite>Distortion-Balance Tests for Motion-Picture Soundtracks</cite>, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977. Available at <a href="https://doi.org/10.5594/J06761" target="_blank" rel="noopener">https://doi.org/10.5594/J06761</a></span>
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Ralph R. Wells; Distortion-Balance Tests for Motion-Picture Soundtracks, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977
doi: 10.5594/J06761
url: https://doi.org/10.5594/J06761
doi: 10.5594/J06761
url: https://doi.org/10.5594/J06761
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<li> Ralph R. Wells; <cite id="bib-10-5594-j06761">Distortion-Balance Tests for Motion-Picture Soundtracks</cite>, SMPTE Journal ( Volume: 86, Issue: 9, September 1977); SMPTE, 1977 <span class="doi">10.5594/J06761</span> </li>