Universal Audio Apollo Software User Manual
Page 107
Apollo Software Manual
Chapter 7: Multi-Unit Cascading
107
External
When using an external clock with Apollo multi-unit cascading, both Apollo units are
automatically configured by the device drivers to use the external clock when the Clock
Source setting on the monitor unit is set “External” (the Clock Source setting only needs
to be changed on the monitor unit).
Important:
When synchronizing to external clock, connect the external clock
source to the monitor unit
only. The expander unit always synchronizes to the
monitor unit.
Multi-Unit FireWire Bandwidth
Bandwidth Consumption
When multi-unit cascading while connected to the host computer via FireWire, more
FireWire bandwidth is consumed by the additional I/O streams, so less bandwidth is
available for UAD plug-ins used within the DAW.
Note: FireWire bandwidth is not consumed by UAD plug-ins used within Console,
nor when Thunderbolt is used for the host computer connection. The UAD Band-
width Allocation does not apply in these scenarios.
Use of Hard Drives on FireWire Bus
To keep FireWire bandwidth available for UAD plug-in processing within the DAW when
multi-unit cascading, running FireWire hard drives for audio session files on the same
FireWire bus as Apollo is not recommended. Using USB, eSATA, or internal hard drives
for audio session files is recommended instead.
Recommended Multi-Unit UAD Bandwidth Allocation Values
The values in the table below are recommended as starting points when tuning the UAD
Bandwidth Allocation with multi-unit cascading. See
“Optimizing FireWire Performance”
for complete details about this setting.
Multi-Unit Cascading
Recommended UAD Bandwidth Allocation Values
Sample Rate (kHz):
44.1, 48
88.2, 96
176.4, 192
Mac:
Apollo
Apollo 16
70%
60%
50%
35%
N/A*
Windows:
Apollo
Apollo 16
70%
60%
45%
25%
N/A*
I/O buffer setting for
best playback results
512
1024
N/A*
*Multi-unit cascading is unavailable at these sample rates