Steinberg Nuendo DD8 Mode D'emploi page 27

Unfortunately, LOCK does not necessarily mean that the received sig-
nal is correct with respect to the clock processing the read out of the
embedded data. Example [1]: The Nuendo DD 8 is set to 44.1 kHz inter-
nal and a CD-Player is connected to input AES1. The INPUT LED will
show LOCK immediately, but the CD-Player's sample rate is generated
internally, and thus slightly higher or lower than the Nuendo DD 8's in-
ternal sample rate. Result: When reading out the data, there will fre-
quently be read errors that cause clicks and drop outs.
Also when using multiple inputs, a simple LOCK is not sufficient. The
above described problem can be solved elegantly by setting the Nu-
endo DD 8 from INT to INPUT (its internal clock will then be the clock
delivered by the CD-Player). But if you now connect a DAT recorder as a
second source, there will again be a slight difference in the sample rate,
and therefore clicks and drop outs [2]. Another example could be con-
necting to ADAT machines which are not synchronous to each other
due to wrong clock setup [3].
In order to display those problems optically at the device, the Nuendo
DD 8 contains SyncCheck
they are not synchronous to each other (i. e. absolutely identical), the
SYNC LED of the asynchronous input flashes. In example 1 it would
have been obvious at once that the SOURCE AES LED was constantly lit
when connecting the CD-Player, but that the SYNC LED was flashing. In
example 2, all LEDs would be constantly lit except the SYNC LED of the
input used by the DAT. In example 3, two LEDs are constantly lit, while
two others are flashing.
In practice, SyncCheck allows for a quick overview of the correct config-
uration of all digital devices. So one of the most difficult and error-
prone topics of the digital studio world finally becomes easy to handle.
A special problem occurs with devices offering several AES or SPDIF in-
puts. While with ADAT and TDIF all 8 channels share the same clock
base, with AES there are several completely independant receivers with
own PLLs and data buffers. Therefore there can be a random error of ±
1 sample difference between the stereo pairs. The Nuendo DD 8's ex-
clusive SyncAlign® technology avoids this effect and guarantees sam-
ple synchronicity among all 4 stereo channels.
®
. It checks all clocks used for synchronicity. If
NUENDO DD 8
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