Dolby Laboratories DP570 - Manual (Page 79)

Configuring a Monitor System Calibrating Speaker Playback Levels
Dolby ® DP570 Multichannel Audio Tool User’s Manual 67
A.3 Calibrating Speaker Playback Levels
The following sections discuss and illustrate the steps in speaker calibration in the order
they should be performed. Normally this entire process need only be executed once for
each set of monitor speakers. We do recommend periodic checks to verify that current
settings are still appropriate.
A.3.1 Setting the Digital Reference Level
Set this level to match your studioʹs digital reference level before turning on a test noise
when calibrating your speaker system.
The default value is –20 dB. Adjust it using the dial shown in Figure A‐7.
Figure A-7 Digital Reference Level
A.3.2 Setting the Master Trim
Set the Master Trim shown in Figure 4‐10 to 0.
A.3.3 Setting the Master Volume
Before generating test noise, make sure that master Volume is set low: –20 to –30. Use the
slider shown in Figure 4‐11.
A.3.4 Picking a Target SPL
When picking a target SPL, it is most important that each of the main channels is set to the
same level; the absolute level is secondary. The following examples are suggestions for
selecting an absolute level:
• For film work, test noise at reference level in the main channels (Left, Right, Center)
should produce an SPL of 85 dBc. For film work, Surround channels are calibrated to
an SPL of 82 dBc with Surround 3 dB Attenuation checked. The net result is an SPL of
85 dBc when noise is played through the system.
• For television work, test noise at reference level is typically set to produce an SPL
ranging from 79 to 82 dBc for each of the main five channels. The lower reference level
for television is due to the lower average listening levels used by the consumer
(typically 70 to 75 dBc).
Tip: To make this adjustment you must close the Setup window to activate the main
application screen. When satisfied, reopen the Setup window.