If you are in a room where the windows are closed, the door is closed shut and there is weather stripping around the door and at the bottom, you will not notice the sound outside of the room.  If you open the door a small amount, there will be a noticeable difference in the amount of sound coming into the room.  Just like you can feel the cold rushing into a room in the wintertime when you open the window in the room.  Sound works the same way.

When sound is in the untreated room, the sound waves bounce off all hard surface finishes.  The more it bounces, the more the sound wave is amplified creating an echo in the room.  Echo and reverberation result in an uncomfortable acoustic environment which affects the quality of music being played and the clarity of any communication in the room.                                                       

To resolve unwanted sound from entering the room,  you need an appropriate construction design and all openings need to be sealed properly.  Then to reduce the noise level in the room, sound-absorbing material will need to be strategically placed in the room.

 Ten Interesting Facts About Sound

1. The sound of a whale song can travel a distance of 800 km.
2. Sound with frequencies of less than 20 Hz is known as infrasound. If a sound has a frequency that exceeds 22,000 Hz it is called ultrasound.
3. Sound is a traveling wave which is an oscillation of pressure transmitted through a solid, liquid, or gas.
4. For humans, hearing is normally limited to frequencies between about 12 Hz and 20,000 Hz (20 kHz), although these limits are not definite. The upper limit generally decreases with age.
5. Dogs can perceive vibrations higher than 20 kHz.
6. In the air, sound travels at the speed of about 335 meters (6100 feet) a second. Sound travels about 4 times as fast in water as it does in air.
7. The speed of sound is approximately 343 m/s (1,230 km/h; 767 mph).
8. Sound is transmitted through gases, plasma, and liquids as longitudinal waves also called compression waves.
9. The accepted units for sound pressure are metric, Newton per one square meter (N/m2).
10. Sound waves are invisible because the human eye can’t see pressure waves. But an oscilloscope can detect and show the shape of sound waves very accurately.