Apogee Symphony 64, User Manual, Page: 10 / 60

APOGEE ELECTRONICS
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Symphony64 PCI card – User’s Guide
Word Clock Connections Multiple Apogee Interfaces
As with any digital audio system, all hardware interfaces in your Symphony system must be locked to a common
sample clock. Shown below are three clock configuration options, including setup.
Option 1 - Using the First Hardware Interface as Clock Master
Advantages - least expensive
Disadvantages - BNC “T” connectors may be mechanically unstable;
difficult to integrate other digital devices such as consoles, outboard effects, etc.
• Connect a BNC cable from the first interface's word clock output to a BNC "T" connector installed on
the second interface’s word clock input. Connect the other side of this BNC "T" connector to the next
interface, using additional BNC "T" connectors to extend the chain.
• Continue until all interfaces are connected (as depicted at right), and terminate the last interface's
word clock input .
• In Maestro, set Clock Source Select to Internal .
• Verify that the first interface is locked to internal (INT) and that all other interfaces are locked to word
clock (WC). Verify that all interfaces are running at the desired sample rate.
• As configured, the Apogee hardware will follow the sample rate of the Mac.
Option 2 - Using an External Master Clock (such as Apogee’s Big Ben)
Advantages - most stability, easy integration of other digital devices
Disadvantages - user must manually match the hardware sample rate to the software sample rate
• Connect a word clock cable between outputs of the master clock and each interface’s word
clock input as depicted at right. Be sure to terminate all the inputs.
• In Maestro, set Clock Source Select to External .
• Set the external Master clock to the desired sample rate.
• Verify that all interfaces are locked to word clock (WC).
IMPORTANT - The sample rate of the external clock source must be matched manually to the sample rate
of the Mac, as determined by the DAW session or the sample rate setting in Audio MIDI Setup.
Option 3 - First Hardware Interface is Master, Big Ben clocks all remaining interfaces
Advantages - most stability, easy integration of other digital devices,
hardware follows software sample rate
Disadvantages - When using Rosetta 800s and a Big Ben,
the first Rosetta 800 isn’t clocked to Big Ben.
• Connect a word clock cable between the first unit’s word clock output and Big Ben’s word clock input.
• Connect a word clock cable between Big Ben’s outputs and the remaining interfaces’ word
clock inputs. Be sure to terminate all the inputs.
• In Maestro, set
Clock Source Select
to
Internal
.
• Clock Big Ben to its word clock input (WC).
Clock varispeed operation up to +- 4.5% of the nominal sample rate is supported.
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