Audio Precision APx500 Flex User manual

APx500 Flex Setup Guide
RME Fireface 802
Overview
Before an RME Fireface 802 can be used with APx500 Flex, the device driver must be installed and
the gain settings configured using TotalMix FX and the GAIN/VOL knobs on the front of the interface.
48V phantom power may also be enabled. Follow the steps below to set up your device.
Driver installation
1. Download the latest Fireface 802 device driver for your operating system from the RME website.
RME offers both Firewire and USB drivers for this interface, however we recommend only using
the USB driver.
2. Install the driver.
3. Connect a powered Fireface 802 to your computer.
4. Reboot the PC.
Configuring “TotalMix FX”
1. Launch TotalMix FX from the Windows taskbar.
The TotalMix FX application icon.
2. Select Options Operational Mode from the application menu.
3. Select “Digital Audio Workstation Mode”. This mode simplifies the TotalMix FX application view
by hiding unnecessary settings.
The Operational Mode dialog.

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4. Click OK to confirm the change. The TotalMix FX application will automatically close if the
workstation mode was not already selected.
5. Re-launch TotalMix FX from the taskbar.
6. Select File Load Workspace from the application menu.
7. Load the workspace supplied with this setup guide. A Fireface 802 has four front panel Mic/Line
inputs which can be used via either the XLR or TRS/TS (Inst) connections. The workspace file
provided is configured for the XLR inputs.
8. If prompted to discard all changes, click Yes.
At this point your view should resemble the screen capture,below.
The configured TotalMix FX application.
Note: the TotalMix FX software has a drop-down in its upper-rightmost corner for switching between
USB and Firewire settings. Loading a workspace file configures both sets of settings. This toggle may be
unavailable if you have only ever made one type of connection with the interface.

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Configuring Phantom Power
When using a phantom power microphone, the 48V phantom power setting should be enabled
on the appropriate input channel. With the Fireface 802, Hardware Inputs “Mic 9” through “Mic 12” in
the TotalMix FX application represent the four Mic/Line inputs on the front of the interface. With the
TotalMix FX application open,
1. Click the settings wrench adjacent to the meter of the microphone input requiring phantom
power.
The settings button for the first microphone input.
2. In the panel that appears, click the button labeled “48V” to enable phantom power on that
channel. An orange highlight indicates phantom power is enabled, whereas dark gray
indicates the setting is disabled.
3. Repeat for the other microphone inputs, if necessary.
Configuring the Hardware
In addition to configuring the TotalMix FX software, the gain and volume knobs on the interface should
be set as follows:
1. Set all four Mic/Line “GAIN” knobs to the minimum setting (+6).
2. Set both Phones “VOL” knobs to the maximum setting (10).
Calibration from Project File
Once both TotalMix FX and the RME hardware have been configured, the output and input
scaling factors should be entered into the APx500 software on the appropriate channels to allow
accurate generation and analysis in analog units. To simply this process, Audio Precision has provided a
project file with these settings pre-configured. Load the project to finish calibrating your APx500 Flex
analyzer.

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The project file is set up for the following inputs and outputs:
a. All four front panel XLR inputs
b. Back panel line inputs 1-4
c. Back panel line outputs 1-8
Manual Calibration
Alternatively, use the guide below to manually select channels and apply the appropriate scaling factors.
1. Run APx500 Flex.
2. Set “Device” to “ASIO Fireface USB” in either the output or input configuration panel.
3. Open the ASIO Settings dialog using the settings cog button next to a Connector drop-down.
4. Disable “Auto Map Channels”.
5. Map the desired output and input channels. The ASIO channel and hardware channel
correlations are described in the table below.
6. Close the settings dialog.
7. Set the output “Scaling Mode” to “Analog”.
8. Set the output scaling factor based on the outputs mapped, using the table below as a
reference. Note that only one output scaling factor can be configured.
9. Set the input “Scaling Mode” to “Analog”.
10. Set the input scaling factor for each channel based on which inputs were mapped, using the
table below as a reference.
Note: if the front panel unbalanced TS inputs are used instead of the XLR inputs, Instr. mode will need to
be enabled on those channels in the TotalMix FX application. For additional information on the
appropriate TotalMix FX settings see the footnotes below.
Output & Input Sensitivities
Hardware Output Connection Type ASIO Output Sensitivity
Line Level Outputs 1-8
Balanced/Unbalanced
Analog 1-8
3.4 V/FS*
Phones 1
Unbalanced
Analog 9-10
5.4 V/FS**
Phones 2
Unbalanced
Analog 11-12
5.4 V/FS**
Hardware Input
ASIO Input
Line Level Inputs 1-8
Balanced/Unbalanced
Analog 1-8
280 mFS/V*
Front Panel Mic (XLR) Inputs
Balanced
Analog 9-12
400 mFS/V***
Front Panel Line (TS) Inputs
Unbalanced
Analog 9-12
110 mFS/V****
*Measured with channel trims set to +4 dBu.
**Measured with headphone “VOL” knobs set to max (10).
***Measured with “GAIN” knobs set to min (+6), Instr. mode disabled.
****Measured with “GAIN” knobs set to min (+6), Instr. mode enabled.
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