M-Audio Fast Track Ultra User Manual page 13

Fast Track Ultra
External Signal Status
This box displays messages indicating the current synchronization status:.
If the status in the Clock panel (see the Clock section below) is set to "Internal, " the External Signal Status panel will
display this message:
"Because the clock has been set to 'internal' you may use the sample rate controls to
adjust the sample rate and external signals will be ignored. "
You will be able to adjust the sample rate using the arrows on the Sample Rate Settings box above.
It is recommended that you do not change the sample rate from the Control Panel while your DAW application is
running, as this can cause some applications to exhibit unexpected behavior.
If the status in the Clock panel (see the Clock section below) is set to "external, " and a valid digital signal is received
at Fast Track Ultra's S/PDIF input, the External Signal Status panel will display this message:
"Because the clock has been set to 'external' the sample rate controls may not be adjusted. However, because
there is a valid external signal, the sample rate will automatically match that of the external signal. "
The arrows on the Sample Rate Settings box above will be disabled and the sample rate box will display the
incoming sample rate.
If the status in the Clock panel (see the Clock section below) is set to "external" but no valid digital signal is
received at Fast Track Ultra's S/PDIF input, the External Signal Status panel will display this message:
"Because the clock has been set to 'external' the sample rate controls may not be adjusted. While there is no
valid external signal, the sample rate will remain 48kHz. "
Clock
These two buttons select between the internal clock or the clock from an external digital signal via the S/PDIF
input . To synchronize Fast Track Ultra to an external digital source, the "external" setting must be selected.
20
Please see the box below for more information on digital input and external clock.
About External Clock
Digital audio is based on samples. For example, a digital recording at a sample rate of 44.1 kHz contains 44,100
samples, or digital "snapshots," per second. Each digital audio device has its own internal clock, or crystal, to generate
and control the exact rate and timing of these samples during every second. In order for two or more digital audio devices
to function together, only one of their clocks can be in control (the Master), while any other devices must be synchronized
to that device's clock (the Slave). Otherwise, the resulting audio will sound distorted, play at the wrong speed, or have
clicks and pops.
You can set Fast Track Ultra to run as the Word Clock Master ("Internal") when digitally connected to other digital audio
devices:
Connect the S/PDIF output of Fast Track Ultra to the S/PDIF input of another digital audio device and configure that
device to synchronize to its S/PDIF input (making it the word clock Slave).
Alternatively, you can set another device to act as the Word Clock Master and designate Fast Track Ultra to run as the
word clock slave: Connect the S/PDIF output of a 3rd party audio device to the S/PDIF input of Fast Track Ultra. Select
"external" as the clock source setting from within the Fast Track Ultra Control Panel. Fast Track Ultra now runs in sync to
the digital S/PDIF signal generated by the other device. Note that Fast Track Ultra can only receive input signal from its
S/PDIF input when the clock setting has been set to "external. "
User Guide 12 12