Well, this sounds like an interesting topic.
To dispel this myth about marble sounds, why don't arrange with
neighbors directly above and the adjacent unit above, and get
someone to go up with some marbles to test?
I live on the top floor of an HDB flat, and have never heard
marbles dopping. Accept for one ocassion when I was staying at
another older flat on the top floor as well. Being on the top
floor, one would not expect to hear any sounds coming from above as
it is the roof of the flat. But I too, heard marble being gently
dropped - you can hear the tik-tik-tikity-tikity-tik-tik
sounds.
I ignored it, and did not acknowledge hearing it. Never mentioned
aloud that I heard it.
It stopped.
