Double Bungalow

[Roger Klimek]

I own a duplex (side by side) and would like to better soundproof the home.  We have hardwood floors which does not help.  I can sometimes hear TV's, the stereo, and voices through the heating or return vents, and am not sure why since there are two seperate furnaces.  I am guessing that sounds travel into the walls and ceilings and then travel through the duct work.  Can anything be done to solve this noise problem?  I also have dropped ceilings in the basement and would like to know if I can better soundproof the ceiling which might prevent sound from traveling to the ducts.