User`s guide

User's Guide Babyface © RME
23
9.9 Clock Modes - Synchronization
In the digital world, all devices must be either Master (clock source) or Slave (clock receiver).
Whenever several devices are linked within a system, there must always be a single master
clock.
A digital system can only have one master! If the Babyface’s clock mode is set to 'Internal',
all other devices must be set to ‘Slave’.
The Babyface utilizes a very user-friendly, intelligent clock control, called AutoSync. Selecting
Optical as Clock Source, the system constantly scans the digital input for a valid signal. If any
valid signal is found, the Babyface switches from the internal quartz (Clock Mode – Current
Internal) to a clock extracted from the input signal (Clock Mode – Current ADAT or SPDIF). The
difference to a usual slave mode is that whenever the clock reference fails, the system will
automatically use its internal clock and operate in clock mode Master.
AutoSync guarantees that record and record-while-play will always work correctly. In certain
cases however, e.g. when the inputs and outputs of a DAT machine are connected directly to
the Babyface, AutoSync may cause feedback in the digital carrier, so synchronization breaks
down. To solve this problem switch the Babyface clock mode to Master (Clock Source – Inter-
nal).
In some situations changing the clock mode can not be avoided. Example: A CD player is con-
nected to the SPDIF input. Try recording a few samples from the CD and you will be disap-
pointed - few CD players can be synchronized. The samples will inevitably be corrupted, be-
cause the signal from the CD player is read with the clock from the Babyface, being out of sync.
In this case, the Clock Source should be set temporarily 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 the optical input, or if there is a valid and synchronous signal
(Sync). In the field Clock Mode the clock reference is shown. See chapter 26.1.
Under WDM the Babyface will (has
to) set the sample rate. Therefore the
error shown to the right can occur. A
stable signal with a sample rate of 32
kHz is detected at the ADAT input
(Sync), but Windows audio had been
set to 44100 Hz before. The red color
of the text label signals the error
condition, and prompts the user to set
32000 Hz manually as sample rate.
Under ASIO the audio software sets
the sample rate, so that such an error
can not happen. If the input sample
rate is different then there will be no
Sync indication.
With RME’s AutoSync and SyncCheck, finally anyone can master this common source of error,
previously one of the most complex issues in the digital studio world.