I purchased a Dell XPS 13 9360 (the new model). Overall, while clearly audible, I can live with the coil whine from the laptop. However, when I plug in my headphones, I can very clearly hear the coil whine over music while it is playing.
When I first boot my laptop, there is only a small amount of clicking through the headphones. The issue seems to only occur after suspending the laptop for the first time, and can only be fixed by rebooting.
I am running Fedora 26 with all of the updates applied as of writing, and I have followed the instructions on https://wiki.archlinux.org/index.php/Dell_XPS_13_(9360)#Continuous_hissing_sound_with_headphones . Any ideas?