Setting in game sounds to max then controlling windows audio did not work for me either.
I also tried to lower the audio quality/sampling rate from 48kHz down to 44kHz, which did not work.
I did find something that works however, but isn't really viable for me.
I have the CoolerMaster Storm Sirus 5.1 headphones, which, as the name suggests, are 5.1 surround headphones. The headphones come with their own bundled software where you can change a lot of settings.
What removed the echo for me completely was changing the headphones from 5.1 Surround to Stereo. However doing this results in my audio being extremely quiet, to the point where maxing out all audio settings still leaves it quiet.
So although this does work, I'd rather stick with the echo than not hearing anything.
I'll use the tool and submit a report as was mentioned in one of the earlier reports.
