Types of Sounds
There are two types of sounds:
Airborne — These sounds are transmitted by way
of the air and can be absorbed by insulation.
Structure-Borne — These sounds are generated by
vibrations in the ground and/or a structure and must be interrupted
to reduce or eliminate the transmission of sound energy.
Many sounds are both airborne and structure-borne.
For example, speech is an airborne sound until it strikes a
wall and becomes structure-borne. This causes a vibration that
travels through the wall and once again becomes airborne sound,
audible to listeners in an adjacent room.