CTS Verifier Pro Audio Test

Android 10 and higher include a CTS Verifier test for Pro Audio compliance, which tests round-trip audio latency. Unlike many CTS Verifier tests that run automatically, the Pro Audio test requires human intervention to select and connect an appropriate peripheral to the device under test (DUT).

Selecting an audio peripheral

An appropriate peripheral is one that has sufficient playback and record functionality and can directly connect to the DUT to accurately measure round-trip latency through the audio path. Because analog, digital, and Bluetooth headsets can't be directly connected to device outputs and inputs, these peripherals are not appropriate peripherals and can't used for the Pro Audio test.

Acceptable peripherals include the following:

  • USB audio interface. This peripheral can be any USB audio interface that can have its outputs and inputs directly connected to the device with patch cables. All mandated USB audio interfaces required by the USB Audio Peripherals Play or Record CTS Verifier test meet this peripheral requirement.

    CTS Pro Audio USB Interface

    Figure 1. Example USB audio interface

    When using a USB interface with input level controls, you might need to adjust the controls to a nonzero value; this is typically done when calibrating the signal level. If the audio interface passed the USB Audio Peripheral Record test, the input level setting used in that test should work in the Pro Audio test as well.

  • Loopback plug, USB-C digital-to-analog adapter

    CTS Pro Audio USB-C Adapter

    Figure 2. Loopback plug with USB-C digital-to-analog adapter

  • Loopback plug, 3.5 mm analog jack

    CTS Pro Audio 3.5 mm Analog Jack

    Figure 3. Loopback plug with 3.5 mm analog jack

Running the Pro Audio test

To run the CTS Verifier Pro Audio test:

  1. Directly connect an appropriate audio peripheral to the DUT.

  2. On the device, launch the CTS Verifier app.

  3. In the list of tests, select Pro Audio Test.

  4. In the Pro Audio Test module, verify that the test prerequisites are met (values are true or N/A), then tap Round-Trip Test.

    CTS Pro Audio Test Module

    Figure 4. CTS Verifier, Pro Audio test module

  5. Use the returned values to verify that all CDD Pro Audio requirements have been met.

    • For latency criteria, see Professional Audio.

    • To get a sufficient Confidence value, you might need to run the test more than once.

  6. Tap Green Check to indicate compliance.