Dolby Laboratories Multichannel Audio Tool DP570 - Manual (Page 81)

Calibrating Speaker Playback Levels
Dolby ® DP570 Multichannel Audio Tool User’s Manual 65
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).
• For music mixing, each speaker channel should be set to the same SPL (the same as
television mixing). There is no standard practice for reference levels for music mixing.
Some engineers prefer to mix louder than others do, but if the levels between channels
are correct, the overall level is not as important.
When mixing for television or music in small mixing rooms such as remote recording
trucks, surround channels are generally set 2 dB lower than the front channels. This takes
into account the short distance to the surround speakers. Experience has shown that this
setting makes the sound in the home environment very close to the sound heard by the
mixer.
Tip: To make this adjustment you must close the Setup window to activate the main
application screen. When satisfied, reopen the Setup window.