How do I fix echo or feedback coming through the speakers when using the webcam?

You need to adjust both the output and input audio levels through your system's sound settings. In Windows 10, right-click the speaker icon in the taskbar, select Sounds, and configure the output level under the Playback tab and the input level under the Recording tab for your microphone. Similar steps apply for Windows 8.1 and Windows 7 via the Control Panel. (Page 11-12)