You want to achieve your neighbour being quieter, for the long term, and I think you already understand that for that to happen it will be better to have an, at least, cordial relationship with your neighbour.
At present you know very little about your neighbour, beyond the fact that they live in an apartment and don’t go to bed early, so the degree to which you can tailor your approach to their personality is limited, but whatever you DO do:
Don’t go and hammer on his door when you are angry.
Consider the encounter from his perspective, some stranger turns up
at your door wanting you to change your behaviour, and possibly spend
money to make their life nicer. What would make you want to be
helpful to that stranger?
Here are some things to consider:
Timing and realism
Go at a time which seems convenient to his schedule as far as you can
figure from what you can hear. Try not to go when he’s just leaving
for work for example, or at the start of the period which you find
Don’t expect him to have an instantly effective solution.
If your neighbour is going to have to rearrange his furniture, get rugs, have a fridge-ectomy, buy slippers… none of that is going to happen instantly so try to come up with a timing which minimises the amount of time you both get to spend dwelling on what the other said/did/is doing/isn’t doing. That’s a recipe for folk getting angry. Can you broach the subject at a time when you are about to go away for a weekend or a business trip or something to take that ‘it hasn’t got better yet’ pressure off a little bit?
Focus on Outcome
Don’t tell him what he needs to do; most of us don’t like getting instructions from strangers. And really, it matters not a jot to you whether his solutions is to turn his apartment into a huge ball pit that he swims through, attach helium balloons to his belt for added lift or learn to levitate.
What you care about is the outcome. So don’t tell him he needs to spend money or change his lifestyle, let him know that there is a solution.
‘I don’t know what’s different but I really never heard the last
Make it clear that you are blaming the fabric of the building, not him
‘I’m really concerned that if the building transmits sound so much, I
might be bothering you with my TV/music/Digeridoo practice’
Most of us react well to being though well of. If people treat us as though they think we are a stand-up person, we tend to value that assessment and try to live up to it. If they assume we are a waste of space, we tend not to value their opinion (since they are clearly a poor judge of character) and therefore don’t feel any need to improve their opinion of us.
While it may be overkill to try to convey that this heavy-footed neighbour is a pillar of society right off the bat, at least avoid opening the exchange with anything that gives away that you think he is a fridge eating hephalump.
- Exude the conviction that he is a stand-up fridge-eater who is going
to be really happy to do whatever he can, in fact you are concerned
that he doesn’t get carried away and go too much out of his way,
spend too much to accommodate you.
- Try to avoid making him feel as though you have an uncomfortable
level of insight into his life from what you can overhear as that may
make him react defensively. Keep statements general rather than
specific, ‘movement sounds’ or ‘footsteps’ rather than ‘you walking
between the fridge and the john all night.’
So an ideal exchange might be something like
Hi neighbour, welcome to the building, sorry I didn’t get a chance to
say ‘Hi’ sooner. How are you finding the place?
.... chit chat follows
Something I wanted to say, the reason I knew I had a new upstairs
neighbour was that the soundscape changed completely. I don’t know
what the difference is, but somehow I hear your footsteps/moving about
a lot more than I used to hear the last guys. So I wanted to check
that I wasn’t bothering you with my flugelhorn practice, (I’m totally
going to get a muffler for that thing) and to ask if there might be
something you could do in the future to soften the sound from your
side? I don’t want to put you on the spot, you couldn’t have known how
this building transmits sound, so I’ll just leave you with that
thought. I’m off for a couple of days now on a flugelhorn retreat with
my collective, so you’ll get a break from me at least. Ciao
Okay, so I’ll never get a job writing sitcom dialogue, but I’m sure you can find your own way to bring those ideas together.
Forgot to say: if he makes changes that work thank him.