Theta Digital Casablanca III, Owner'S Manual

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Setup Dolby Digital
Button # 3 provides a two page sub menu which allows the user to set up preferences pertaining to Dolby Digital
(AC-3), by INPUT SELECT button. The first page of this sub menu is shown in figure 91.
Figure 91 -
Video Display of the SETUP / INPUT Page 2 / DOLBY DIGITAL Page 1 Sub Menu
2 Channel Mode
Some Dolby Digital sources contain only two of the possible five main channels. This is usually noted on the
material's cover, in the form of " Dolby Digital 2.0" or “Dolby Surround” as opposed to "Dolby Digital 5.1".
Embedded in every two-channel Dolby Digital data stream is an indication of whether or not the material is Dolby
Surround encoded. There are three possibilities for this indication: Dolby Surround encoded; Not Dolby Surround
Encoded; or No Indication.
Regardless of the indication value, the user can instruct the Casablanca III to further process this decoded signal in
virtually any
MODE . For Dolby Surround encoded signals, use button # 1 ( 2CHEN – or 2 channel encoded) to
indicate which MODE should be used to further process the incoming signal. Use button # 2 ( 2CHNEN – or 2
channel non-encoded) to indicate which MODE is desired for further processing, if the signal is non-encoded. When
a mode is applied to a two channel Dolby Digital signal, first the signal must be Dolby Digital decoded, then this
decoded signal is manipulated by the selected mode that is selected in the
2CHEN or 2CHNEN parameters. When
this is the case and the additional selected mode is MATRIX , the MODE displayed in the VFD when in the INPUT
SELECT MENU will say “ DOLBY D MATX ”
If the indication is that the signal is not Dolby Surround encoded, or there is no indication, and the
2CHNEN MODE is
set to Dolby Digital, no additional surround processing will occur, thus producing a two-channel (stereo) output.
Compression
Dolby Digital contains provisions for reducing the dynamic range of a Dolby Digital source. This means reducing the
loudness of the loud passages and increasing the loudness of the quiet passages. Possible reasons for reducing the
dynamic range of a source include late night listening wherein loud moments may disturb others, and making tapes
for automotive / portable use wherein quiet passages may not be heard.
Casablanca III contains three parameters to control Dolby Digital compression. Button #
3 ( COMPRESSION ) simply
turns the compression ON or OFF . Button # 4 ( HI COMPRESSION ) controls the amount of volume that loud
passages will be reduced. Button # 5 ( LOW COMPRESSION ,) controls the amount of loudness that quiet passages
will be increased. A larger number indicates a greater amount of increase or decrease.
Note : Some Dolby Digital sources do not allow for compression, in which case altering these settings will not result
in an audible change.
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