The ear in a human body is said to be the most sensitive and powerful radar available in this world. Apart from its unique capacities of sensing, filtering and identifying a large variety of sounds in the spectrum of audible frequencies - in its most general state, a healthy ear in the human body can as well sense smaller (low in pitch and loudness) sounds from long distances if the external disturbances are removed. For instance, we can hear the buzzing sound of a bee from about 6ft in an otherwise silent surrounding. Controlled experiments in advanced telecommunication centers (including AT & T Bell Labs, New Jersey, USA) have recorded several such extraordinary sensing capabilities of human ears. These include the successful 'listening' of the physiological tremors by different groups of human subjects under different soundproof experimental conditions.
Modern technology is still far away from developing an electronic analogue of the natural device like the human ear. The fine sensor - the tympanum,
inside our ears - is made up of an ultra-thin membrane of thickness of about 4 X10-10
inches only. Even in the average normal conditions, i.e., without any practice of Nada
Yoga, the sensing power of this unimaginably thin membrane is about ten thousand times more than that of the most powerful sensor developed by the state of art technology till date.
Theoretical analysis of the models of the structure and functioning of the human ear indicates that it can discriminate about four hundred thousand different kinds of sounds. There have been noted musicians who could recognize the individual sound of each of the hundred odd instruments being played jointly in an orchestra.