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Hearing and psycoacoustics page

    General information

    The human hearing system is an incredibly sensitive sensor system withextensive signal processing in the brain.All sound professional and other people workign with audio system should educate themselves about hearing loss and hearing conservation. The idea that you're responsible for the health and safety of your own ears is common sense. But you may be responsible for somebody else's when you operate anything that makes lots of noise or high level audio signals. You must also understand hearing to understand the operation of hearing to be able to get the good sound on any system. The thing is to understand what is the most important and what is less important in sound is necesary to optimize any sound system. You shoudl play back the important parts best, and if necessary save on those less important ones. The ear can respond to a remarkable range of sound amplitude. (Amplitude corresponds to the quality known as loudness.) The ratio between the threshold of pain and the threshold of sensation is on the order of 130 dB, or ten trillion to one. The judgment of relative sounds is more or less logarithmic, such that a tenfold increase in sound power is described as "twice as loud". The just noticeable difference in loudness varies from 3 dB at the threshold of hearing to an impressive 0.5 dB for loud sounds.Loudness is the psychophysical response to the stimulus of soundpressure, and is a VERY complex response. The subjectiveresponse to the "loudness" of a sound is dependent upon how loudit is to begin with, it's frequency, it's spectral content, thepresence of other, possibly masking sounds, the recent historyof sound perceived (temporal masking) and many other factors.Examples of the complexity: it rquires a MUCH larger differencein power at low frequencies to result in a subjective doublingof loudness than it does at 4 kHz. It requires a largerdifference in power at low sound pressure levels to perceive adoubling than it does at higher SPL'sBut there is no "equation" which relates changes in SPL tope4ceived loudness changes. There are reasonable approximations,and they are not simple. But the often heard "10 dB difference needed for aperceived doubling" is a rul-of-thumb that's reasonably validfor a specific set of circumstances only.

    Psycophysics

    The operation of the ear has two facets: the behavior of the mechanical apparatus and the neurological processing of the information acquired. The mechanics of hearing are straightforward and well understood, but the action of the brain in interpreting sounds is still a matter of dispute among researchers. The mechanisms of sound interpretation are poorly understood, in fact is not yet clear whether all people interpret sounds in the same way. Most studies in psycho-acoustics deal with the sensitivity and accuracy of hearing. This data was intended for use in medicine and telecommunications, so it reflects the abilities of the average untrained listener.

    • Hearing and Perception - The operation of the ear has two facets: the behavior of the mechanical apparatus and the neurological processing of the information acquired. The mechanics of hearing are straightforward and well understood, but the action of the brain in interpreting sounds is still a matter of dispute among researchers.    Rate this link

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