Background sounds are useful, but can be monotonous, which is why for a while I ended up with https://www.youtube.com/watch?v=w1o4O2SfQ5g instead, varies a bit but still has no gaps. Of course, nothing's more potent I find than heavy metal, but it can have gaps... my problem also is mostly with inconsistent engine noises, don't mind too much regular ones as long as they're not loud... but the combination of absolutely loud and sudden... is giving me PTSD (without the post...), I think... earlier just my cat opening a door made me think it's the nightmarish engine, just because the door has some minor bass sound... also, I doubt anyone can do anything so I could move, I was actually in a better place, but they made sure to screw me over...