Sound is the effect of matter resisting matter.
Where there is no matter, e.g. a vacuum, there is no sound.
Where there is no resistance, there is no sound.
All matter is energy with its own uniquely energetic vibration.
Sound is a physical vibration not an energy vibration.
When different energetic vibrations of matter resist each other, they cause a different, physical, vibration called sound.
The paradox of sound is that without a physical vibration receiver, the sound doesn’t make a sound.
My ear is a physical vibration receiver, which I call my hearing organ.
In normal use, it is a sensitive detector of changes in the rate of the physical vibration of air molecules.
It is less sensitive to the rate of vibration of liquid molecules, when I am submerged in water.
The denser the medium that surrounds my ears, the less sensitive my sense of hearing becomes.
For sound to be an effect, it requires a cause.
The cause of sound is the motion of matter relative to other matter or the interaction of matter in resistance to other matter.
Without motion, there is stillness & no sound.
Stillness is the absence of sound and calm is the absence of the motion that causes sound.
Sound is the medium through which the physical sense of hearing becomes activated.
Without sound, there is no physical sense of hearing.
Without the physical ability to hear, there is no apparent sound; just the presence of matter energetically vibrating in its own unique way.
It is not necessary for matter to interact with other matter and make a sound for me to intuitively sense that it is energetically there.
I physically hear (sense) the physical vibration of matter, I intuitively sense (hear) the energetic vibration of matter.