Well I would start by completely removing the driver and re-install and verify it is the latest driver.
- Open an elevated command prompt and type pnputil -e
- Locate your Realtek audio driver it will probably look like this View attachment 31914
- Make note of the oem#.inf name
- Type pnputil -d oem10.inf in my case
- Download and reinstall the latest driver from the computer manufacturer site
- Reboot and test
If it still has the echo I would suggest ruling out hardware. Download
Download Ubuntu Desktop | Download | Ubuntu and use a tool like
Rufus - Create bootable USB drives the easy way to create a bootable usb. Boot into the Ubuntu installer and select Try. This will boot into a live version of Ubuntu. Go to Youtube and see if the echo is there. If it is then I'd say it's a hardware problem with your speakers.