From a frequency of approx. 15hz (oscillations per second) upward our hearing perceives a tone.

Our tactile perception (skin surface, finger tips) senses oscillations as vibrations up to 400hz. The oscilations that we hear and feel are called vibro-acustic.

By the perception of tones there is the basic difference of the perception of sound waves as pressure fluctuations of the surrounding air, converted from the ear into a heard tone and the waves transferred by direct body contact 'Körper­schall' - structure-borne sound.

You experience this in everyday life: we do not recognise the recording of our own voice. It sounds foreign to us because we perceive our voice in the main over our body, you can say from our inside. Violinists as well hear their instrument primarily through structure-borne sound.

The vibro-acoustic has become increasingly the field of bases and aplied research in different areas of sience and research during the last 20 to 30 years. For example, in the car and mechanical engineering, but also in the medical research.

We deal often in the everyday life with effects of the vibro-acoustic. Whether we feel the noise of a big machine or a means of transportation as pleasant or tiresome (research subjects in technical highscools are from the car industry supported projects which frequency have to do a car on his passengers transferred and which not). The noise and the vibrations on ships with big, slowly running engines is experienced in general as reassuring, quick ferries with high-speed gas turbines rather than hectic and in the long run unpleasantly.

From many parents I have already belonged that they have risen in the middle of the night with her baby in the car to drive rounds around the block because that was the only way to calm down the worried, weeping child and bring it to fall asleep.

Different attempts to the investigation and application of the vibro-acoustic in the area of the wellness and therapy are to be found in sound couch basics.