Why I hear sound from downstairs clearer than sound from upstairs? In all the houses of two levels where I have been, why I hear the sound from downstairs clearer when I am at the second level, than I hear sound from upstairs when I am at the first level?
Does sound  travel upward more easily than downward?
Do the architectures of houses matter much?
 A: This is an interesting question. I regret that I don't know the answer for sure, but I can say that sound does not travels in any substantially different way upwards vs downwards. Rather, I believe the answer has to do with the fact that low frequencies are carried through the physical structure differently because of where they are: things that make sound tend to be in physical contact with the floor, not the ceiling, and that physical contact carries extra low-frequencies.
Imagine a stereo: it is physically connected to the floor (perhaps through a bookshelf) which conducts the low frequencies downstairs, and creates a muddy sound. Upstairs, however, they don't get those additional low frequencies, just the air->ceiling->air sound, so it's a bit clearer (albeit quieter).
The same logic would apply to children running, furniture moving, and even people speaking.
A: I have a theory. Since the first floor is anchored to the ground and is likely concrete, both act as a buffer. Imagine a speaker playing music. Now touch the speaker. The level decreases dramatically. Think of your finger as earth. It more mass than the speaker cone. It has more potential energy than the speaker has kinetic energy, thus drastic attenuation.
Now the second floor is only anchored to the first floor. This would be similar to adding a second speaker cone to the first cone. Since the mass of the second cone is close to the first, very little attenuation occurs.
Have you noticed the same effect on a pier and beam house?
