Apogee Symphony 64, User Manual, Page: 40 / 60

APOGEE ELECTRONICS
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Symphony64 PCI card – User’s Guide
VBus Selections - Apogee’s VBus creates virtual hardware buses to allow expanded routing of audio within
one application or between different audio applications. For example, it’s possible in Logic Pro to record
a submix of multiple audio tracks onto a new audio track as described below. It’s also possible to route
between two audio applications by selecting a VBus output in the source application and a VBus input in the
destination application.
To engage VBus , open Apogee’s Maestro application, select one of the Apogee interfaces connected to the
Symphony PCIe card, and open the Maestro Control window. In the VBUS Selections drop down menu,
select the number of virtual buses desired.
In order for VBus I/O to appear in your audio application’s I/O list as VBus In 1-2, 3-4 , etc, it’s necessary to
specify the use of the Symphony driver’s names in the application’s I/O list. For example in Logic Pro, open
Audio>Audio Configuration>View>I/O Labels and option-click on all the I/O found under the Driver’s I/O
Label column.
As an example of how to use VBus, let’s record a submix of drums onto a new stereo audio track in
Logic.
First, open Maestro and select 8 Channels under the VBus Selections menu.
In Logic’s Track Mixer, set the outputs of the individual drum audio tracks to VBout 1/2. Create two audio
tracks (or one stereo track) and set their inputs to VBin 1 and VBin 2 . Record-enable the new track and
commence recording. The new track will record the mix of the individual drum tracks.
Performance Tuning allows the adjustment of Symphony driver buffers to take advantage of the latest Intel
Macs’ increased CPU power.
Set Performance Tuning to High Performance when using Symphony 64 on an Intel Mac. This reduces
buffer sizes and ensures the lowest latency through the Symphony system.
Set Performance Tuning to Standard when software buffer settings won’t resolve clicking and popping
issues.
Performance Tuning is set in addition to the buffers typically found in digital audio applications. If audible
clicks and pops are encountered, first raise the driver buffer size in the audio application. Apogee’s extensive
testing of this driver indicates that software buffers will “run out” before the Symphony driver buffers controlled
by Performance Tuning . If problems persist set Performance Tuning to Standard .
Maestro Control Window
Settings Pane
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