Internet bandwidth speed affects audio and video quality. In addition, streaming or downloading other items while in a Discuss.io session can also affect the quality.
Other things to keep in mind:
WiFi is not as stable as a wired connection. A wired connection is recommended for attending sessions.
If WiFi is being used move as close as possible to the router.
Make sure other tabs on the browser are closed and there are no current downloads active.
Disconnect other devices or users sharing the connection (e.g. XBox,
video streaming, downloading).
The connection quality of the other participants may have an effect, and extreme connection distances can also cause latency issues when video chatting.
The more participants in a session, the more possibilities for issues and slower speeds.