Limit Bandwidth - RME Audio Fireface 400 User Manual

To cope with some situations which may arise in studio practice, defining a sync reference is
essential. One example: An ADAT recorder is connected to the ADAT input (ADAT immediately
becomes the AutoSync source) and a CD player is connected to the SPDIF input. Try recording
a few samples from the CD and you will be disappointed - few CD players can be synchronized.
The samples will inevitably be corrupted, because the signal from the CD player is read with the
(wrong) clock from the ADAT i.e. out of sync. In this case, the Clock Source should be set tem-
porarily to SPDIF.
RME's exclusive SyncCheck technology (first implemented in the Hammerfall) enables an easy
to use check and display of the current clock status. Input Status indicates whether there is a
valid signal (Lock, No Lock) for each input (Word Clock, ADAT, SPDIF and LTC), or if there is a
valid and synchronous signal (Sync). In the field Clock Mode the clock reference is shown. See
chapter 35.1.
In practice, SyncCheck provides the user with an easy way of checking whether all digital de-
vices connected to the system are properly configured. With SyncCheck, finally anyone can
master this common source of error, previously one of the most complex issues in the digital
studio world.

20.3 Limit Bandwidth

This option helps to reduce the amount of bandwidth used on the FireWire bus. A typical exam-
ple is the use of the Fireface with a laptop. Only in rare cases the ADAT port is needed, in many
cases it stays unused. The option Analog+SPDIF will reduce the amount of constantly (!) trans-
ferred data from around 3 MByte (6 in both directions) to only 1.7 MByte (3.4 in both directions).
The FireWire connection will be more stable, reliable and robust, leaving additional bandwidth
for other devices. At the same time the CPU and system load is reduced, as less channels have
to be processed and to be transferred. In TotalMix, the deactivated software playback channels
will be replaced with empty plates. More details are found in chapter 35.4.
Available Settings
All channels (default) activates all 18 input and output channels
Analog + SP. + ADAT 1-4 activates all 8 analog channels plus SPDIF plus 4 ADAT channels
Analog + SPDIF activates all 8 analog channels plus SPDIF
Analog 1-8 activates only the first eight analog channels
User's Guide Fireface 400 © RME
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