I have the same issue, did you resolve this or discuss with dell under warranty?

M15 r2 2070 max q. 

It's defo not the fans and is very loud and concerning, certain games cause it to be worse such as fortnight, barely noticeable on the witcher, slight issue with apex legends.

All drivers are upto date etc. 

After 2 weeks of them "investigating" which was, them reviewing videos I made of the noise...they didn't give me any tech help they just said to take it back to the store. I was pretty angry at that.

It's not resolved, and I've just got used to it. It's annoying, because it only seems to happen on some games. When it happens, it's horrible.

Good luck!

Oh great

Thanks for the update though

This guide will help you to troubleshoot the crackling issue on your laptop:

https://www.dell.com/support/article/en-us/sln117556/troubleshooting-sound-problems-on-your-alienware-systems?lang=en

We used the method described in it to solve the crackling sound of almost all of the Alienware laptops in our Office (O365CloudExperts),

I hope this helps!

Thanks for the response, the sound I have an issue with does not come from the speakers, it is a noise from the components when under load. 

I think it's coil whine but a particularly bad case. 

Guaranteed if you start a new thread about your laptop they will ask you to send a video clip of the problem (there's no upload video function on here, so you have to mess around uploading to Youtube...) and then they will get back to you 2 weeks later and tell you to return it where you bought it, without offering any suggestions at all.

My experience was a complete and utter waste of time, coupled with the waste of money that I spent on a crackling laptop.

Try adjusting your bass and treble settings in the Alienware sound center.

Next thing I’d do is Do a ePSA test but click the 7 beep audio test and see the results.