If you have transferred the system of the Google AIY project to your already installed Raspbian system, you will find that both the audio output and the voice input are not yet working.
To install the necessary drivers, simply open a new terminal window and enter the following commands.
Please note that an active internet connection is required.

After the restart is complete, enter the following commands:

Before restarting your system, you need to modify the check_audo.py-File and execute it:

Append the following line to the start of the file, right before the import of the aiy.audio is done:

The beginning of the file should look like the following:

Save the file with the combination CTRL+O and close the file with the combination CTRL+X.
Now execute the file:

Warning! Currently there is a misconfiguration within the source-files provided by google. Even when the execution of the file is showing an error, the execution is still successfull.
You can skip the error by pressing Enter.

You can now test whether both the microphone and speaker are functioning.
Simply record a voice recording with the following command:

The recording can be completed with the CTRL+C key combination and then played back with the following command:

You should now be able to listen to your previously recorded voice file.