User Manual-Mac

EXPANDING YOUR PCI-424 SYSTEM
103
SYNCHRONIZING MULTIPLE INTERFACES
The entire PCI-424 system gets its clock from
whatever you choose from the Clock Source menu
in the MOTU PCI Audio Console window.
Synchronization across all connected interfaces is
sample-accurate. All available sync sources on all
connected interfaces are displayed in the menu as
demonstrated below in Figure 11-4.
Figure 11-4: The entire PCI-424 system can be clocked from any sync
source on any connected interface. After you choose a source from
this menu, the entire system, including all connected interfaces,
synchronizes to it with sample-accurate precision. This example
shows three 2408mk3 interfaces and one 24I/O interface.
Word clock connections are not necessary
Each MOTU PCI audio interface in the system gets
its clock from the Audio Wire cable connection to
the PCI-424 card (unless it is the master clock
itself). There is no need to make word clock
connections between interfaces.
SAMPLE RATE ISSUES
While the PCI-424 card can operate at sample rates
as high as 192 kHz, not all MOTU PCI audio
interfaces support the higher rates. When choosing
high sample rates (above 48 kHz) interfaces that do
not support the rate will be temporarily taken off
line by the system. For complete details, see “Clock
Source” on page 66.
PCI BANDWIDTH ISSUES
Attempting to run 96 channels of 96 kHz audio
input and output (that’s 192 channels total) places
extreme demands on your computer’s PCI bus.
Today’s fastest computers can just barely handle
this much data on their PCI bus. Slower computers
will lower the number of banks you can use at one
time. See “Disabling banks to conserve resources”
on page 70 and “PCI use” on page 71 to learn more
about managing your system’s PCI resources.