M-Audio Delta 66 User Manual page 22

Once a master clock source has been selected, its synchronization status is
continually monitored and displayed below the master clock radio buttons. If
internal crystal is selected, the status display will always say "Locked." On the other
hand, if S/PDIF In is selected as the master clock source, the control panel will
display "Locked" only when a valid S/PDIF signal is detected. It will display
"Unlocked" when there is no signal at the S/PDIF input, or when the signal is corrupt
or invalid for any reason.
CODEC SAMPLE RATE: This section indicates the present board sample rate, as
set by application software. The sample rate displayed here is used to drive the
digital mixer and all outputs. The "Rate Locked" checkbox is used to force a sample
rate upon the system. It is disabled by default to allow software access to all
supported sample rates. When checked, it causes the driver to only operate at the
selected sample rate. This means that any application that attempts to open the
Delta 66 driver at a sample rate other than the one selected here will fail to do so and
will post an error message. "Reset Rate When Idle" is selected when you want the
sample rate to return to a particular setting when a software application is not
actively using the board. This is particularly handy for keeping the digital mixer
running at a specific sample rate.
NOTE: Because the digital monitor mixer runs at the sample
rate of the rest of the board, and because sample rate directly
affects frequency response, it may sometimes be desirable to
keep the sample rate at or above 44.1 kHz while using the
monitor mixer. This is accomplished by enabling "Reset Rate
When Idle" and selecting a sample rate of 44.1 kHz or greater.
S/PDIF SAMPLE RATE: When using S/PDIF In as your master clock, this section
tells the driver what the expected S/PDIF input sample rate is. The section is only
displayed when the board is set to use S/PDIF In as the master clock source. From
the list, select the sample rate closest to that of the S/PDIF input data. The sample
rate selected here will be the only sample rate available to the software applications.
Therefore, you must set your audio software application to this same sample rate or
else the application will display an error message.
NOTE: When S/PDIF In is the master clock source, the digital
monitor mixer will run at the sample rate received at the S/PDIF
In. Since frequency response and sample rate are directly
related, the mixer frequency response will be directly related to
the sample rate of the S/PDIF input data.
MULTITRACK DRIVER DEVICES: The Delta 66 drivers may intelligently
synchronize the beginning of recording and playback across all audio devices on the
board. When using application software that is capable of using multiple channels
simultaneously, select "Single and In-Sync" to ensure that all audio channels will
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