It's easy to understand that both sound and vibration play a role in acoustics, but it's less obvious to know how they interact.
Understanding the differences and how they interact is essential to avoid mistakes.
What is sound?
Sound is vibrations transmitted through a solid or a liquid or gas, with frequencies in the approximate audible range of 20 Hz to 20 kHz.
Vibrations with frequencies lower than 20 Hz (infra sound) or higher than 20 kHz (ultrasound) cannot be heard but under certain circumstances, can be felt. But we will concentrate here on the audible range.
If sound is transmitted trough a solid a liquid or gas, a human ear is made to receive sound trough air.
Our ear drum will detect a sound wave that impacts it and will transform it into a different form of energy.
We speak of airborne sound, or sound transmitted through air.
Airborne sound can be detected or measured by a microphone.
For a sound wave to reach our ear or a microphone, it has to propagate in air but it also needs to be somehow generated. Air particles will be put in movement to create the sound wave by a vibrating object. It can be a musical instrument (with the exception of wind instruments), vocal cords or any object vibrating at a frequency within the audible range. In that sense, a loudspeaker cone is a vibrating object.
This vibration can propagate trough air (as see above) but also through solids and liquids.
In that case we speak of structure borne sound, or sound transmitted trough objects.
Structure bone sound can be detected or measured by an accelerometer.
The fundamental difference between airborne and structure borne sound (or noise) is important to keep in mind because it will determine the way we tackle the problems. Confusion in that matter will result in inefficient measures, meaning wased time and money.
To simplify, I will call airborne sound "a sound" and structure borne sound "a vibration" .