TYPES OF SOUND- AIRBORNE SOUND STRUCTURE BORNE SOUND Airborne sound originates in a space with any sound producing source and although it changes to structure-borne sound when the sound wave strikes the room boundaries it is still referred to as airborne because it originates in the air. Structure sound is generally understood as energy delivered by a vibrating or impacting source directly contacting the structure. Hence a child crying in an adjoining apartment is contributing to airborne sound but the same child bouncing a ball on the floor is creating structure-borne sound,in this case by impact. DISTINCTION BETWEEN AIRBORNE AND SRUCTURE-BORNE SOUND All sound transmission is both airborne and structure-borne since,once having entered the structure,the sound travels along the structure and causes the structure to vibrate,in turn generating airborne sound. Airborne sound is generally much less disturbing than structure borne, since its initial energy is very small and it decreases ra...