Chapter 3 installation issues, 1 venting, 2 timing and delays – Dolby Laboratories S01/13621 User Manual
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Dolby Installation Guidelines
3-1
Chapter 3
Installation Issues
3.1 Venting
The Dolby professional audio products are designed to operate within a temperature
range of 5° to 45° C. They use natural convection cooling and therefore should not be
mounted directly above any heat-generating equipment.
DP-series products, with the exception of the DP570, have vent holes in the top and
bottom panels, along the left or right edge, depending on the unit (left side for the
DP562, DP571, and DP572; right for the DP563 and DP569). The vent holes should
not be covered, although units can vent through one another if necessary. In this
event, be sure that the venting panels are on the same side on each unit. The number
of units that can be vented in this way will depend on the conditions of the room in
which they will be installed.
The DP570 features vent holes in the front and back of the unit, and can be placed
directly above or below other rack-mount gear.
3.2
Timing and Delays
Encoding and decoding adds delay to the audio data. In audio-only situations this
may be of little consequence, but where the audio has associated video material, care
should be taken to ensure that these delays are accounted for. This can be done by
adding the equivalent delay to the video stream, by compensating for the delay at the
video encoding stage, or by adding an offset between the time code of the source
tapes. The amount of the delay varies depending on the technology being used.
3.2.1 Dolby
Surround
The delay associated with the Dolby Surround encode/decode process is effectively
zero. The DP563 does allow for the encoding delay to be varied between minimum
(<1 ms) and 100 ms. The DP562 has little latency (approx 3msec@48kHz) when in
Disabled or Reference bitstream detect modes, although this increases if bass
redirection is used. When in Silent Switch mode, the decoding latency will be the
same as for Dolby Digital. Silent Switch mode includes a crossfade when the input
switches between different formats.