Audio Precision APx500 Flex User manual

APx500 Flex Setup Guide
Echo AIO-A2
Overview
Before an Echo Audio AIO-A2 can be used with APx500 Flex, the device driver must be installed and
the settings configured using the Echo AIO Control Panel. CCP power may also be enabled. Follow the
steps below to set up your device.
Driver installation
1. Connect a power cable to the Echo interface and the interface to a PC via USB.
2. Install the device driver on the PC, following the prompts displayed.
Device configuration
1. Launch the Echo AIO Control Panel.
2. On the Channels tab, set the Gain on all inputs to “1x Gain”.
3. Set the range of all outputs to “+-10V”.
The Echo AIO Control Panel
4. View the Settings tab.
5. Set the ASIO Buffer size to “2048 samples.”
6. To ensure the device playback and recording volume is set to 100%, temporarily enable the
“Windows audio” checkbox as shown below.
The “Windows audio” and “ASIO buffer size” settings

APx500 Flex Setup Guide - Echo AIO-A2.docx 2
7. Open the Windows “Sound” control panel.
a. View the Playback tab.
b. Right-click on Speakers (Echo AIO) and select “Properties”.
c. View the Levels tab and set the level to 100 (the maximum).
d. Confirm changes.
e. View the Recording tab and repeat steps “b”. through “d.” for device “Line (Echo AIO)”.
The Windows “Sound” control panel
8. Switch back to the Echo AIO Control Panel and disable the “Windows audio” checkbox.
Enabling CCP power
Many measurement microphones (such as the GRAS 46AE, a free-field microphone often used
to test loudspeakers) require Constant Current Power (CCP) in order to function. To enable CCP on one
of the AIO mic inputs, open the Echo AIO Control Panel and enable the “Constant Current” checkbox
next to the desired input channel.
Configuring the APx500 software
Once the device has been configured, the output and input scaling factors must be entered into
the APx500 software on the appropriate ASIO channels to allow accurate generation and analysis in
analog units. Use one of the following methods to configure APx500.
Project file method
To simplify this process, Audio Precision has provided a project file preconfigured for the
following inputs and outputs:
•Inputs: MIC1 – MIC8 (BNC).
•Outputs: AMP1 - AMP4 (Euroblock)
Load the project file included with this setup guide to finish the setup process.

APx500 Flex Setup Guide - Echo AIO-A2.docx 3
Note: if the APx500 analyzer is licensed for less than eight ASIO channels, the number of mapped output and input
channels will be automatically reduced to the number of licensed channels. To increase the number of licensed
channels, please contact your sales representative using the information provided on the Audio Precision website.
Manual configuration method
Use the steps below to manually configure the APx500 software for use with your Echo interface.
1. Start the APx500 software.
2. Set “Device” to “ASIO Echo AIO” in either the output or input configuration panel.
3. Open the ASIO Settings dialog by clicking the cog next to either the output or input Connector
drop-down (see image below).
ASIO Settings cog location
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 to “9.55 V/FS”.
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.
Output & Input Scaling Factors
Interface Output1, 3Connection Type ASIO Output Channel Sensitivity
AMP 1-4
Euroblock
Analog 1-4
9.55 V/FS
Interface Input2, 3 ASIO Input Channel
MIC 1-8
BNC
Analog 1-8
0.16 FS/V
1Measured with outputs set to +-10 V.
2Measured with input gains set to 1x.
3Measured with Windows Playback and Recording device volume set to 100%.
© 2021 Audio Precision, Inc. All Rights Reserved. XXI07151553