Dell C2422HE User Manual page 103

If the USB cable and the HDMI or DP cable are connected from monitor to the
computer, two speakers named DELL C2422HE/C2722DE/C3422WE and Echo
Cancelling Speakerphone (C2422HE/C2722DE/C3422WE) respectively from
the monitor will show in the Sound setting interface. The difference between DELL
C2422HE/C2722DE/C3422WE and Echo Cancelling Speakerphone (C2422HE/
C2722DE/C3422WE) is only different signal source. You can choose either one to set
as the default speaker for monitor.
Operating the monitor | 103