Yamaha DS2416 Mode D'emploi page 12

10
Wordclocks
Wordclocks
Unlike analog audio equipment, digital audio equipment must be synchro-
nized when digital audio is transferred from one device to another, otherwise,
the digital audio might not be read correctly and audible noise, glitches, or
clicks may occur. Synchronization is achieved using what's called a wordclock,
which is a clock signal for synchronizing all the digital audio words in an
audio system. Note that wordclocks are not the same as SMPTE or MIDI
timecode, which are used to synchronize audio recorders, MIDI sequencers,
and so on. Wordclock synchronization refers to the synchronization of the
digital audio processing circuits inside each digital audio device.
In a typical digital audio system, one device acts as the wordclock master and
the other devices act as wordclock slaves, synchronizing to the wordclock
master. If the DS2416 is the only digital audio device in your system, no spe-
cial wordclock settings are required, as the DS2416 synchronizes to its own
internal wordclock. Add a DAT recorder or digital multitrack recorder, how-
ever, and you must decide which device to use as wordclock master and which
devices to use as slaves. Even when you've done this and configured your sys-
tem, it may sometimes be necessary to change the wordclock settings, such as
when recording from a DAT or CD player.
Wordclocks run at the same frequency as the sampling rate. The DS2416 gen-
erates its own wordclock at 44.1 kHz (the industry-standard sampling rate for
music CDs) or 48 kHz and can be used as wordclock master. Alternatively, it
can be used as a wordclock slave synchronized to an external wordclock of
between 30.08 kHz and 50.88 kHz (32 kHz –6% to 48 kHz +6%). Converting
the sampling rate of digital audio is a complicated process, so it's best to use
the 44.1 kHz sampling rate, especially if your work is destined for CD distri-
bution.
Wordclock signals can be distributed via dedicated cables or derived from
standard digital audio connections, such as the D IN and D OUT connections
on the DS2416. With Coaxial digital audio connections, a wordclock signal is
transmitted even when no audio signal is present. The DS2416 can also trans-
mit and receive wordclock signals via its SI, SO, IO-A, and IO-B connectors.
In a system where all devices share a common wordclock, it's important that
all devices be turned on even when they're not being used. Turn on the word-
clock master first, and then the slaves. When shutting down the system, turn
off the slaves first, and then the master. Before commencing with a recording
session, make sure that all wordclock slaves are synchronized to the master.
Some devices have front panel indicators to show when they are wordclock
synchronized. Refer to the instructions for each device.
DS2416—Owner's Manual