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| Movie Surround Formats A good movie soundtrack is a complex interplay of sound fields: the actors’ voices clearly fixed on the screen, the sound effects positioned according to where they would be if the audience was in the middle of the scene, and the music enveloping the audience in a natural manner. The soundtrack is “designed” in a dubbing theater that has sound mixing and movie screening equipment, and encoded with one or more of the movie sound formats (see Brief Guide to Movie Sound Formats). Movie Theater Sound Versus Home Theater Sound However, even though the sound formats using Dolby and DTS technology improve sound localization, movement and other factors, they cannot provide the same sense of “presence” and “realism” obtained in a movie theater. The major difference between a movie theater and a home entertainment room is of course, the size. If theater sound was reproduced with no modification in a home, there would be a big difference in the feeling of scale. Another difference is in the number and positioning of the speakers. In a movie theater, the sound is designed so that it can be accurately reproduced using numerous speakers embedded in the left, right and rear walls and positioned so that they emphasize the relationship between sound from the screen and from each channel. This provides a more uniform quantity of sound to the wide audience area. The overwhelming advantage of CINEMA DSP is that it complements and expands the Dolby- and DTS-processed sound to overcome the differences in facilities, acoustics and dimensions between movie theaters and home listening rooms. In other words, it is able to preserve the localization and directionality of the sound track as it was created by the movie sound designer, while creating a soundscape that gives the sensation of being as expansive as in a theater. Further, with surround sound programs specifically designed to match certain movie genres, the sound can actually be a more accurate reflection of what the director and sound engineer intended listeners to hear. |
 Sound Field Measurement and Analysis There are three basic sound source directions as seen from the listening position: the front direction, the left rear direction and the right rear direction. In developing its surround sound programs, Yamaha used proprietary techniques perfected over the years to measure the virtual sound sources in these three directions: the sound field created by the center speaker, representing the front direction, and the two sound fields made by each of the multiple surround speakers in the left and right rear directions. These are shown in the illustration: Virtual Sound Source Distribution in a Dubbing Theater. Each diagram for the virtual sound sources in the three sound fields shows a completely different pattern of distribution. The effects of the multiple surround speakers on the wall surfaces are observed in the right and left surround channel sound fields. Each of these three sound fields is treated independently, providing the ideal digital sound processing for the various Dolby and DTS sound formats.
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| Brief Guide to Movie Sound Formats •Dolby Pro-Logic Dolby Lab’s basic 4-channel format, widely used in ordinary theaters and for home videos. •Dolby Pro Logic II Improved version of Dolby Pro-Logic for music and movies. With a more intelligent matrix decoder, it is suitable for both stereo and surround-encoded sources. It offers “bass management” as well as the option of incorporating “width,” “dimension” and “panorama” controls. •Dolby Digital The most popular 5.1-channel home theater sound system. An improvement over Dolby Pro-Logic in that it offers: 1) Full frequency response in all channels (3Hz — 20kHz), 2) discrete surround channels, and 3) a separate track for bass only, called the Low Frequency Effects channel. •Dolby Digital EX Dolby's latest surround format, this is Dolby Digital with an added center rear channel. The rear center channel is actually matrixed into the two rear channels, and is extracted upon playback. (Formerly called Dolby Digital Surround EX, or Dolby Digital Matrix 6.1.) |
•DTS Digital Surround The basic DTS 5.1 channel sound format. Uses a higher data rate than Dolby Digital. •DTS-ES Matrix 6.1 Very similar to Dolby Digital EX. Uses a different rear center channel decoding method. •DTS-ES Discrete 6.1 DTS-ES uses its large bandwidth to provide a fully discrete rear center channel, as opposed to a matrixed one. •DTS Neo:6 Provides 5.1 or 6.1 channels of matrix decoding from stereo matrix material. Also decodes Extended Surround matrix soundtracks and has a Music mode to expand stereo non-matrix recordings to 5.1 or 6.1 channels. •DTS 96/24 Delivers 96kHz/24-bit high resolution audio for 5.1 channel surround sound on DVD discs. The benefits are greater bit depths for extended dynamic range and high sampling rates for wider frequency response. |
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CINEMA DSP [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]
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