Configure your Audio

Before starting a call, it is recommended to configure your computer audio settings, bearing in mind that a microphone set too high may cause others on the conference call to hear audio as distorted.

To configure audio click on the gear icon on the right hand side, then select Tools followed by Audio Device Settings. Select the preferred audio device located under Select the device you want to use for audio calls. After the device has been selected and tested click OK.

When you join a meeting with computer audio its recommend that you use a headset rather than a computer microphone and speakers. This will reduce the likelihood of echo and feedback.

Source: https://www.westuc.com/en-sg/user-guides/skype-business-conferencing-best-practices