How do I turn off audio echo from microphone to local speakers?

Sound Settings (GUI)

In "Sound Settings..." choose Hardware and change from "Analog Stereo Duplex" from the Profile selection to "Analog Stereo Input" for usage as microphone or "Analog Stereo Output" for use as speakers.

Command line

From the command line we need to know the index and possible profiles of cards installed. Both will be listed with

pacmd list-cards

To change the card profile we may issue

pacmd set-card-profile <index> <profile>

Where we have to give appropriate values for the card-index we want to set up, and the profile desired.

Examples

The following examples show the commands for a standard internal audio card with index 0 for values corresponding to the GUI:

pacmd set-card-profile 0 input:analog-stereo  # for Input
pacmd set-card-profile 0 output:analog-stereo  # for Output
pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo # for Duplex