noise reduction

I own a raise ranche home that is split into a 2 family house, 1st and 2nd floor.
I recently put hard wood flooring in my living room. The gaps where the wall and floor meet I used caulk to seal off that bit of space, thinking it will block some noise. The wall plugs I used electric foam covers that go inside the plate.
I managed to cut down the noise level I hear from the 1st floor a little. One of the problems is noise coming from the 1st floor where the 1st floor door is. There is an almost 1 inch gap under the door. Is there something I could do to muffle the noise a little without replacing the door.
I was wondering if anyone also has any other advice on muffling the noise coming from downstairs.
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yo wrote:

Before you close off that inch space under the door, make sure it is not needed for air circulation as in heating and cooling.
Take a look at: http://www.soundproofing.org /
Note: I have no connections with them, but they do have some good information. The little I have ordered from them was fine.
--
Joseph Meehan

Dia duit
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