Dolby Laboratories CP750, Руководство пользователя

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Dolby
®
CP750 Digital Cinema Processor Manual 43
Chapter 6
Aligning the Auditorium
The CP750 allows you to quickly and easily optimize the sound quality in the auditorium.
The alignment process is discussed in the following sections:
• Checking Theatre Equipment
• Microphone Placement
• Initial Setup
• Calibrating the Internal SPL Meter
• Initial Output ‐ Level Adjustment
• Room Equalization
• Final Output ‐ Level Calibration
• Final Sound Check
• Nonsync Level Adjustment
6.1 Checking Theatre Equipment
Thoroughly check the loudspeakers and power amplifiers for any sources of poor
performance, using the checklists below as a guide.
6.1.1 Speakers
• Check loudspeaker cable condition and confirm that the cables are the correct gauge
for the impedance of the speakers and the length of the run.
• Check that the speakers are connected to the correct power amp channel.
• Check for leaks in the low ‐ frequency driver cabinet which may sound like rattles.
• Check for loose bolts or other hardware.
• Check the speakers with an ohmmeter. If one channel requires markedly more
equalization than the other, or if one speaker overloads at lower levels than the other
speakers, an open driver circuit could be the cause. In systems with pairs of drivers,
one voice coil of the pair may be open but the system will still function.
• Check for missing drivers or other components.
• Verify that crossover settings matching the type of drivers in use and the acoustics of
the theatre. The high ‐ frequency driver level control must be set for the best possible
frequency response before you attempt any equalization. This is especially true if the
system uses active crossovers with biamp equipment.
• Check for proper polarity between the low ‐ and high ‐ frequency drivers, and between
the channels.
• Ensure that the speakers are correctly aimed into the auditorium, and that they are
not obstructed by the screen frame, struts, or other objects.