AP Flex Setup Guide

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Prerequisites

• Echo ATS powered on and connected to your computer via USB
• Echo ATS Windows driver installed (includes the ASIO driver). See Downloads
• APx500 Flex installed on the same computer
• A measurement microphone connected to an ATS mic/line input
• A speaker or driver connected to an ATS amplifier output

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Setting Up the ASIO Connection

1

Set the Connection to ASIO

Under Signal Path Setup in APx500 Flex for Output and Input connector settings, set the connection type to ASIO.

2

Select ASIO Echo as the Device

From the ASIO device dropdown, select ASIO Echo.

If “ASIO Echo ATS” does not appear in the device list, confirm that the ATS is powered on, connected via USB, and that the Echo driver is installed. You may need to restart AP Flex after installing the driver.

3

Set Scaling Mode to Analog

Set the scaling mode to Analog for both the output and input. Without the correct scaling, AP Flex cannot accurately convert between digital values and real-world voltage or SPL measurements.

4

Enter Output Scaling Factors

Enter the appropriate output scaling factor based on the output mode you are using on the ATS:

Output Mode	Scaling Factor
Line (unbalanced)	4.0 V/FS
Line (balanced)	8.0 V/FS
Headphone	3.0 V/FS
Amplifier/Speaker	9.545 V/FS

5

Enter Input Scaling Factors

Enter the appropriate input scaling factor for the ATS input you are using:

Input Type	Scaling Factor
Mic-Line	161.6 mFS/V
Impedance VMON	80.80 mFS/V
Impedance IMON	161.6 mFS/V	(1mV = 1mA)

6

Set the microphone sensitivity in AP Flex

If your microphone has TEDS data, you can read the sensitivity from the ATS Control Panel’s TEDS window. Check “Show inverse units” to display sensitivity in Pascals/Volt, which is the format AP Flex expects. See the ATS User Manual for details.

The microphone sensitivity can also be measured using a multifunction sound calibrator.Enter the microphone sensitivity in AP Flex under Signal Path Setup for the input channel. This allows AP Flex to convert the measured voltage back into sound pressure level (SPL) for accurate acoustic measurements.In this example we are only using one microphone input. So we unchecked ‘Auto channels’ and set the number of channels to 1.

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Running a Basic Acoustic Test

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Hardware Setup

1

Configure the ATS Output

Open the ATS Control Panel and set the output channel connected to your speaker to AMP mode. This configures the output as a floating differential amplifier output suitable for driving speakers directly.

Amplifier outputs are floating and not ground-referenced. Do not connect the ground terminal when using AMP mode. Connect the speaker across the + and - terminals only.

2

Configure the ATS Input

In the ATS Control Panel, configure the input channel connected to your microphone:

• Gain: Set to the appropriate level for your microphone. Start with +0 dB and increase if needed. Use the lowest gain setting that provides sufficient signal level for the best dynamic range.
• CC (Constant Current): Enable if using a CCP/IEPE/ICP powered measurement microphone.

3

Position the Microphone

Place the measurement microphone at the desired test position relative to the speaker. For a basic frequency response measurement, position the microphone on-axis with the speaker at a consistent, known distance.

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Running the Measurement

1

Select a Measurement

In APx500 Flex under the Navigator, click the ‘Add Measurement’ button and select an acoustic measurement such as Frequency Response or THD+N. These measurements will use the signal path you configured above.

2

Run the Measurement

Click the Run button to execute the measurement. AP Flex will generate the stimulus signal through the ATS amplifier output, and capture the microphone response through the ATS input. Results will be displayed in the AP Flex measurement graphs.

3

Verify Results

Check that the measurement results are reasonable:

• Signal levels should be well above the noise floor
• No clipping should be visible on either the output or input (check the ATS Control Panel meters)
• The frequency response shape should be consistent with the expected behavior of your speaker and microphone

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Troubleshooting