Don t put an area rug over a very long pile carpet such as a frieze or a newer soft carpet such as smartstrand because the area rug will not have firm support and will shift buckle and wrinkle.
Does putting a rug on the floor capture sound.
If noise from downstairs neighbors is coming through your floors your first step should be to add carpeting to help dull the sounds.
This has been very sucessfully reduced by mlv on the floor.
Do know that hardwood floors are very susceptible to the vibrations caused by speakers resting on the floor causing sound anomalies.
To further reduce sound transmission add carpet padding to new or existing carpets.
Let s start with the floor.
Rug safety rugs should always be anchored whether used on a hardwood floor or on top of carpet.
Offsetting the rug can allow both patterns equal weight.
On a hard floor an untethered rug is more likely to slide or slip but when layering area rugs over carpet the rug is more likely.
Similarly if you have a more plush style of carpet installed choosing a low profile berber or woven rug is your best bet.
You will need to cover the whole flor as sound is like water and will find the path of least resistance.
Even carpeted floor tiles can help damped audio from above.
There s no need to fully carpet the floor as even a selection of scatter rugs will help.
More likely the sound waves are being re radiated from the floor up and causing acoustical not vibration sound waves.
The top rug does not have to be parallel to the bottom rug.
Do recognize floor surface attenuation.