RE: Dell Inspiron 11 (3147, Mid 2014) makes crackling sound whenever sound is played
The problem with crackling noises is that the cause is hard to track down, but most often the cause is software and software is not covered by the warranty, so you end up "owning" the problem if you keep the laptop past the return period.
I suggest that you perform a system recovery. Doing that will return the laptop back to the exact state it was in when you took it out of the box.
If the crackling is there immediately after the recovery -- before you connect to the internet -- then you could try to make a case to tech support that the hardware is defective and try to get them to install a new motherboard.
If you perform the recovery and the crackling is gone immediately after the recovery, but the crackling does return later, then it is being triggered by a change to your system configuration. A lot of things change the configuration: Windows updates, viruses, software that you or a third party installs, etc. It can be tough to pin it down.