Alesis 03D, Owner'S Manual

Page: 226 / 302

216
Chapter 18—Digital I/O
03D—Owner’s Manual
Wordclock Setup
About Wordclocks
When several digital audio devices are configured in a system, it is essential that they are
all synchronized to a single wordclock source. This is not SMPTE or MIDI timecode
synchronization. Wordclock synchronization refers to the synchronization of the digi-
tal audio processing circuits inside each digital audio device. Typically, one digital audio
device acts as wordclock master and other devices work as wordclock slaves. The word-
clock frequency is the same as the chosen sampling rate.
Even though some systems appear to work okay with several digital audio devices not
sharing a common wordclock (i.e., all devices set to their own internal wordclock), dig-
ital audio data is not processed correctly. In some systems this problem will be very
audible. In others it may cause subtle distortion. Be aware of this.
In a system where all devices share a common wordclock, it is important that all devices
be turned on even when not all of them are being used. Turn on the wordclock master
first, and then the slaves. When shutting down the system, turn off the slaves first, and
then the master. Before starting a recording session it’s a good idea to make sure that all
wordclock slaves are locked to the master wordclock source. Most devices have front
panel indicators to show whether they are locked to an internal or external wordclock.
Selecting a Wordclock Source
With the 03D’s internal wordclock generator, industry-standard sampling rates of
44.1 kHz and 48 kHz are available. When the internal wordclock generator is used, the
03D can be used as wordclock master, with other digital devices working as wordclock
slaves. Alternatively, the 03D can be used with external wordclock rates of between
32 kHz –6% and 48 kHz +6%. An external wordclock can be sourced from the DIGI-
TAL STEREO IN, BNC WORD CLOCK IN, or a pair of YGDAI digital inputs.
1. Use the [DIO] button to locate the D.in Setup page shown below.
2. Use the cursor buttons to select the WORD CLOCK SOURCE options, and
the [ENTER] button to set them.
If you are using a mouse, simply click the options.
If the 03D locks correctly to the selected wordclock source, the respective indicator
appears highlighted.
Note: As the wordclock source is being changed, noise may be produced. So before selecting
a wordclock source, set the stereo output, aux send, and bus out faders to minimum, turn
down your monitor amplifier, and stop all recorders.