To put a note through the noisy neighbour’s door?

[glittertissues]

A few weeks ago I got a new neighbour in next door and I think they’ve got an air lock in their upstairs plumbing. Every time they flush the toilet or have a shower it sounds

Just go and speak to them!

Why put a note through the door.
I imagine that they can hear it too, so its not like they're not aware.
And its not as if they are playing loud music at 3am
They're just going to the bathroom.
strike up a conversation. Ask how they are settling in
Tell them you noticed their pipes probably need bleeding and would they like the name of a good plumber.
Dont shove a note through their door
Its rude

I pressed send too soon on this post stupid phone but you get the gist

I would just give them a knock

Yes knock. I would hate a note