If you're playing in a Party, try Arcade instead. It's in beta, but Arcade completely eliminates the echo problem for games that work.
Go to Parsec's settings and turn Echo Cancelling ON, in the Hosting tab.
- Make sure to enable the setting before people connect to you
- Check if Standard is used in Discord's Settings > Voice & Video > Audio subsystem
- Check if %appdata%\Parsec\harmony32.dll exists (if not, your PC might be blocking it)
- Disable any software for virtual surround sound or audio enhancing, and restart Discord and Parsec from the taskbar icons in the bottom-right
- If you have a complex audio setup for live streaming, that could be the cause. However, I'd recommend using the alternative solutions below
If none of the above fix it, then you're better off using the alternative fixes below.
The Phone Fix
The Manual Fix