The hearing or the Audition is the capacity to hear sounds. It is one of the five direction.
The Oreille is the principal body of hearing.
The transmission of the vibrations of the air medium in the liquid medium present in the Cochlée poses concrete problems dependant on the Physique of the fluids. Let us recall that if a wave Acoustique which is propagated in the Air perpendicularly reaches the surface of a lake, for example, the thousandths of energy only is transmitted to water, the near total being considered. The perception of a sound wave request thus a system complexes amplification, contained in the physiological chain of perception. (see Hearing)
Our auditive system comprises many smoothnesses: Weaver admitted the possibility of distinguishing up to 64 different heights in the semitone, in the neighborhoods of 1 000 Hz. To provide an idea of the measurement of this sensitivity to the heights, one can refer to measurements of the amplitude of the molecular movement; thus in the average field of the audible Frequency S, displacements of the tympanum, with the threshold of hearing, border 10 Nanomètre S (but this sensitivity is much less good for the serious frequencies and acute).
Two thresholds are also important to announce for hearing: one is called the time of integration of the Oreille (it varies from 50 to 100 milliseconds according to the intensity), and the other, the temporal threshold of recognition the height (which is defined in 1/100e of second on average). In short, the perceived sound does not have a precise height and is qualified by the acoustics experts of “slapping”.
The role of the Temps is also essential for the perception of the stamp S (of the color of the instruments, for example) insofar as a persistence always remains after the stimulus which makes it possible to assess the qualities of a sound. On the matter, the experiments of the Hungarian physiologist Georg von Bekesy made it possible to measure the speed to which one was to decrease a sound to have the same subjective impression that if it were stopped instantaneously: with the Frequency of 800 Hz, von Bekesy measured a persistence of 0,14 second approximately. This measurement corresponds to the perception of fast variations of intensity (beats) or heights (trilles). Beyond 6 to 7 vibrations a second, these variations are not perceived any more like distinct.
Finally according to the application of the principle of uncertainty, our perception offers to us a choice between temporal error and error in Fréquence, which results from the Principe of uncertainty of Heisenberg (∆t * ∆f ≥ K = constant). One can know the signal with an error of time given if one admits an error in frequency sufficient and vice versa. The difficulty of physical interpretation is deferred on that of time and the frequency.
Fiu-vro: Kuuldminõ Simple: Hearing
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