M-Audio Delta RBUS Инструкция по эксплуатации онлайн [15/60] 19013

In situations where the Delta R-BUS is synching to an external R-BUS device,

such as a clock from a Roland digital multitrack or digital mixer that has

R-BUS I/O, the Delta R-BUS Audio Card should similarly be configured to

get its master clock from the external R-BUS wordclock data stream, labeled

“R-BUS In.” The reason for this is the same – an R-BUS data stream coming

from an external source is rarely going to be in sync with the Delta R-BUS

Audio Card (or other digital audio devices in the system), even if the sample

rates are set the same. If the master clock were set to use the internal crystal

(or any selection other than the proper R-BUS clock source), then the

incoming R-BUS audio would have "pops," "crackles," and other undesirable

audio artifacts present in it. Instead, setting the master clock to "R-BUS In"

will synchronize the Delta R-BUS Audio Card to the R-BUS input data and its

digital audio will be transferred properly. The special case to consider, again,

is the external unit sending the R-BUS digital audio to the Delta R-BUS card

may be "locked" to the word clock emitted from the Delta R-BUS card. In

these cases, the Delta R-BUS and the external R-BUS device are in-sync, and

the R-BUS data would therefore be in-sync with the Delta R-BUS system

when the Delta R-BUS card is set to “Internal Xtal.”

When using more than one Delta R-BUS card, the second and subsequent

Delta R-BUS cards may be synchronized to the first Delta R-BUS card by

selecting “R-BUS PCI” as the master clock. The Delta R-BUS has

connections on the PCI card that allow you to connect and synchronize

the R-BUS clock on multiple Delta R-BUS cards using the supplied

internal sync cable. This is necessary to prevent the "pops," "crackles,"

and other undesirable audio artifacts that occur in unsynchronized

digital audio. This is covered further in the “Hardware Settings” section

of this manual.

Finally, the S/PDIF In and R-BUS In (as well as R-BUS PCI) options may

be used to operate the Delta R-BUS at non-standard sample rates. When

one of these options is selected, the Delta R-BUS’s sample rate will

automatically match that of the incoming S/PDIF or R-BUS data stream.

NOTE: When either the S/PDIF or R-BUS In is selected as

the master clock source, the Delta R-BUS mixer’s frequency

response will be affected by whatever sample rates you

inject at the S/PDIF or R-BUS In. This is because (1) the

digital mixer operates at the same sample rate as the rest of

the board, and (2) sample rate and frequency response are

directly correlated.