Go upstairs, ask them what's going on and let them know( politely) that it is bothering you. That is the best way I know to deal with something like this.
Otherwise wait for a day or two and see if it stops.
I know how you feel. A couple moved in next door to us a few months ago. Her talking voice is the same volume as mine when I'm having a major hissy fit...!!!
It's so infrequent tho , I was trying to convey it with the dots ... it's quiet for half an hour than bang bang , nothing for 10 minutes bang - strange , rather than annoying , will see how it develops . Saw him when they moved in , not sure if all his wirings right