The only I have seen distorted sound was when playing some music which the processor was being speed limited.  In my case if I opened a new window it would cause the distortion with the processor showing around .4 GHz.

Otherwise, you might see if you can find something in common with the crackling.  Is it a certain type of audio or source?  Is it only when something else happens?  Basically I suppose is try to be aware of what your system is doing at these times..

It's definitely not when the CPU is high. It happened as I was writing this post. Only Spotify and Chrome are open, two tabs. Nothing intensive. As for whether it's all audio sources, I don't know. I would imagine it's not a Spotify issue. Possibly the MaxxAudio software? This software is always asking me what device I plugged into the headphone jack. Seems a bit unnecessary.

In any case, I would expect better from a £1000 piece of technology even if it's running Windows.

So can I get help with this from staff or....?

Well, you listening volume seems about normal.  If it isn't by the processor running slow or overloaded, maybe something else is happening at the same time.  I have seen folks have problems if they had a fluorescent light nearby.  But if you can pin down any info as to when it happens or in relation to something, even software, it might help.

Try not running whatever you are running when it happens.

Other than that, newer drivers are all I can suggest.  

If you check the Audio FAQ, and look at your model of XPS 13, whatever that might be, you may find something.

Keep in mind the source of the sound may also have a volume control.  The combination determines how loud it is.  Of course, it also depends on the playback device  I have seen some folks on this forum which run the volume at 100%.

If 20% sounds really loud to you, you may have the source set too high and it is causing the crackling.

You don't use any third party audio software, since I have heard some types can overdrive the system.

I just updated the driver through the control panel. The problem is now worse and more noticeable.

Well, the listening volume isn't normal. In Windows 10, anything over 20/100 would blow your ears out.

Yeah, I understand that but the Max Audio Pro software that came preinstalled cannot be removed, apparently, as it's linked to the driver. Anyway, its own volume slider matches the Windows one. They're not independent of each other. The volume in spotify I have always set to max... as for YouTube etc, I've never needed to lower the volume. This does not seem like something I should have to do, especially not with a new product out of the box, with fully updated drivers and software.

To further elaborate on the problem, I would describe the audio as stuttering. Like you said, as if the computer were momentarily freezing... thought it is not.

Also, since updating the Realtek driver from their website, the AudioMax whatever it is software has been acting up and not long recognises my headphones as headphones, but rather "speakers", and the sound is awful. Turning off this "profile" removes all enhancement I guess, but without it... the audio is extremely dull. Honestly, I don't know what to make of that. I only know my 7 year old Vaio performed better.

Also it still stutters with the AudioMax thing off.

What is Dell's return policy and how does one get the ball rolling for that? I bought it through Amazon less than 28 days ago.

Okay, so I notice a spike in the CPU, to 100% for a second only, when the audio stutters. How do I identify the cause of that spike?

I would use Resource Monitor.  Keep it open and if you see it and it only lasts for a second, try hitting the print screen button so you can try to pin down what process in the top window is doing it.  It may take several tries to work down to the actual cause.

If it happens on a certain time period it is easier to catch it.  Also, that means it is probably some type of Task which might show up in the task scheduler or something like mail which goes online.  It could be some software updater among other things.

If you can get us a picture of the windows showing high CPU activity we might be able to trace it down.  Starting with the top window and after setting the filter, go to one of the lower ones.