NAD T750, Руководство пользователя

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NOTES:
Direct sunlight or very bright ambient lighting may affect
the operating range and angle for the remote control handset.
The infrared remote control command receiver, located on the far
left of the display window, receives commands from the remote
control. There must be a clear line-of-sight path from the remote
control to this window; if that path is obstructed, the remote
control may not work.
SETTING UP THE SURROUND SYSTEM
To work at its best, the output levels of the T750’s surround
facilities need to be adjusted so that there is an even balance of
sound from all the speakers in the system.
The Delay time for the Surround speakers also needs to be
correctly set for your normal listening position. Refer to the
section “Setting the Surround Delay” in this chapter for more
information.
The adjustment of speaker levels is done using the Test (No. 7),
Channel Select (No. 5) and Level (No. 6) functions on the Remote
Control. It is important first to correctly phase all the speakers in
the system. Check that the positive (+) terminals of the T750
speaker outputs are connected to the positive (+) connector on
the each of the speakers. Refer also to the section “Speaker
Phase” in the chapter “Appendix” for additional information.
Before starting the set-up procedure, ensure that the Centre
(No. 17) mode is set correctly for your speaker configuration. Set
the BALANCE control to the position normally used for stereo
sources (usually the 12 o’clock position).
• With the speakers connected and the VOLUME turned down to
zero, select the Dolby Pro Logic or Dolby 3 Stereo mode using
the Surround Mode button (No. 16) and press Test on the
Remote Control (No. 7 in fig. 4). This generates a test signal
that scrolls to each of the speaker channels (Left
➜
Centre
➜
Right
➜
Left & Right Surround
➜
Left
➜
etc. for Dolby Pro
Logic; Left
➜
Centre
➜
Right
➜
Left
➜
etc. for Dolby 3
Stereo), so that each can be adjusted for equal loudness at
your listening position. The Display Panel shows which
speaker is being fed with the test signal.
Turn the Volume (No. 7; No. 8 in fig. 4) up until the signal is
moderately loud through the Left and Right Front speakers.
• Press the CH.Select button (No. 5 in fig. 4) on the remote
control until “CENTRE” appears in the display. Within the 5s
default time, press the Level
or button on the
Remote Control (No. 6 in fig. 4) to increase or decrease the
Centre speaker’s loudness so that it matches the levels being
produced by the Left and Right speakers. The relative level of
the Centre channel is shown in the Display Panel and can be
changed in dB steps.
• In Dolby Pro Logic or Hall mode Press the CH.Select button
(No. 5 in fig. 4) on the remote control until “R-SUR.” appears
in the display to adjust the Right Surround speaker. Again,
within the 5s default time, use the Level
or buttons
to set the level so that it matches the levels produced by the Left
and Right Front speakers.
• Press the CH.Select button (No. 5 in fig. 4) on the remote
control until “L-SUR.” appears in the display to adjust the Left
Surround speaker. Repeat the same procedure as described
above to match the levels produced by the Left and Right Front
speakers
A more accurate adjustment can be made using a sound level
meter, if available. Set the meter to ‘Slow’ and ‘C-weighted’ modes
and re-check the settings with the meter placed in several different
positions in the general listening area.
If a Sub-Woofer is used on the system, adjust the Sub-Woofer’s level
control so that it is audible, but does not dominate the sound. Sub-
Woofer levels can be later fine-tuned using programme material.
The Level settings are stored in the T750’s memory. They are
automatically recalled when the unit is switched on.
NOTES: In Dolby 3 Stereo Surround mode the Surround channels
are inoperative. Only the Centre channel can be accessed to adjust
in level.
In Dolby Pro Logic with Phantom Centre mode selected, and Hall
Surround Modes the Centre channel is inoperative. Only the Left
Surround and Right Surround channels can be accessed to adjust
in level.
SETTING THE SURROUND DELAY
Because the Surround speakers are usually closer to the listener
than the Front speakers, there is a tendency for the ear to localise
sounds to the rear, because the ear takes most notice of the
sounds that arrive at the head first.
To resolve this problem, the Dolby Pro Logic circuit includes a
Surround delay. This ensures sound coming from the surround
speakers always arrives at the listener’s ears after the sound from
the front speakers.
The exact amount of delay required depends on the relative
distances between the Front and Surround speakers and the
listening position in the room.
First make a note of the distance between the surround speakers and
the listening position. Now make a note of the distance between the
front speakers and the listening area. Note where the two distances
intersect this will give the correct Delay setting (see fig. 5).
To adjust the Delay setting, put the T750 into Dolby Pro Logic
mode and press DELAY on the front panel (No. 18) or the Remote
Control. Continue pressing DELAY until the correct value is shown
in the Display Panel.
The Delay settings are stored in the T750’s memory. They are
automatically recalled when the unit is switched on.
APPENDIX
A SHORT GUIDE TO SURROUND SOUND
Since the middle of the 1970’s, film companies have been making
movies in increasing numbers in Dolby Stereo, the four channel
surround sound system available in most movie theatres today.
Fortunately it is a simple operation to take the film’s Dolby Stereo
soundtrack and place it on a stereo VHS videotape, Laser Disc or
Video-CD. The sound track does require some conversion for
home use, and the domestic version of Dolby Stereo is called
Dolby Surround.
Today, most video copies of movies also contain this surround
information originally designed for the movie theatre. As well as
videos, Dolby Surround is also being used on TV programmes and
on music CDs, and all of these can be decoded using your T750.
Unlike the quadraphonic systems which tried to produce pin-
point sounds coming from all directions, Dolby Surround is
designed to give you a clear front image with the Surrounds filling
the room with atmospheric sound.
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