What can it be if the sound of the smartphone, for example when watching videos, jerks and cracks, even when the doorbell rings, the doorbell cracks?

When I watch films on Netflix or the videos on Facebook, the video jerks and the sound cracks recently. Can someone help me there? I've already cleared the cache.

What's the situation with headphones?

If it doesn't appear there, it's the speakers.

This can of course also be a software problem, but the error sounds like to me: Box broken. The thin magnetic membrane in there will actually be broken. There are 4 options:

It is like that now.
This might work better if it is set less loudly.
You can have it repaired (or do it yourself)
You buy a new cell phone.