MACKIE HDR24/96 - Manual (Page 192)

HDR 24/96
Clock Master /
Time Code Slave
Clock Slave /
Time Code Master
Time Code
Word Clock
Word clock can also come from an external source like a word clock generator, a digital console, A/D
converter, or DAW. As long as all devices lock to the same sample clock, it really doesn’t matter
who generates the clock. The example below illustrates this.
Word Clock Generator
Clock Slave /
Time Code Master
Time Code
Clock Slave /
Time Code Slave
Which method you use is completely dependent on your setup.
How can you Sync to Word Clock and Time Code at the Same Time?
This is a good question, and one that often causes confusion. The following example best illustrates
the answer.
Master HDR24/96 Slave HDR24/96
Time Code
In the example above, the slave receives time code but not word clock from the master. When you
press play on the master, the slave precisely locks its transport position to the master’s position.
However, once the slave HDR24/96 locks to time code from the master, it effectively “ignores” time
code from the master and plays back audio at the Sample Rate generated by its internal Sample
Clock. Because the clocks of the two units are not synchronized, the audio and the time displays
between the two units will drift over time. This example is exactly analogous to the problem of trying
to synchronize two wristwatches to each other.
The answer is that time code is used to synchronize the transport position, and word clock to
synchronize the sample clock rate/speed of multiple devices. Although word clock synchronization
always controls the sample rate of the slave units in the same way, there are two basic ways digital
audio devices handle time code synchronization.
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