My speaker seems broken with no sound

But the sound is okay through headphones?

If so, test with the ePSA diagnostic Quick Audio Check? (see picture)

If you don't hear the test tones in the Perform Quick Audio Check  then there is a hardware failure with the speakers. Contact tech support for a repair if still under warranty.

Thanks Jim, I solved the problem. It seems like the updated drive is not compatible with the system, and the sound is back when I re-installed the old version. Luckily there's no failure with the hardware.

Be careful as my XPS13 has been playing up now for over a year with the sound buzz issue.

Many users are suffering. Nobody has found a real solution.

Mine is ok sometimes and buzzes at other times, no pattern as to when it occurs ie when hot/cold/battery use/on charge etc

I've updated the sound drivers many many times using a range of different ones.

It started when the Anniversary Edition of Windows was installed back in Nov 2016. I'm still thinking that there's a connection with Cortana...or maybe it has driven me so crazy that I imagine all types of things thesedays :)