Great post and hopefully this will help others with a similar problem!
Hi Everyone, XPS 15 9510 - Windows 11 ProVersion:  10.0.22000 Build 22000 Sound Driver:  RealtekDriver Date:  11/2/2021Driver Version:  6.0.9261.1 Issue Playback on the built-in laptop speakers and when Bluetooth pairing Sony headphones was giving noticeable echo on voice recordings.  This issue was discussed with Realteck audio drivers introducing echo on playback, way back in 2019, but the laptop drivers installed are the latest to date from DELL so I was confused as to why the echo? The only way I found to fix this was by modifying the sound playback settings to introduce a Microsoft controlled playback effect.  Thought to pass this tip along to anyone else suffering from playback echo (sounds like you are in a hard walled room, reflecting sound waves). This fixes the echo sound for both headphones and laptop internal speakers. Realtek Driver [IMAGE] Sound Setting - Spatial Select Windows Sonic for Headphones [IMAGE] Hope this helps someone remove their annoying echo! Aly  
XPS 15 9510 - Realtek Sound Echo Solved