Resonant frequency of the eardrum?

Discussion in 'Archived Threads 2001-2004' started by Ryan T, Dec 17, 2001.

  1. Ryan T

    Ryan T Second Unit

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    Hi,

    I've been wondering about the answer to this question for a while and I thought maybe someone here would know. Basically I would like to know what the resonant frequency of the eardrum is or what frequencies damage the eardrum the most? I think it might be in the 1000 to 5000 Hz range but I'm not sure. Also I'm not sure if this is the right forum area to post this question so if it is not could someone tell me a better place to post it, Thanks.

    Ryan
     
  2. Mac F

    Mac F Agent

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    I'm not sure the eardrum has a resonant frequency. Resonance is the natural frequency at which an object will vibrate most easily. This is a function of mass, and length. The eardrm is flexible and will only vibrate as long as it is stimulated. The bones in the ear (malleus, incus and stapes) will have individual resonant frequencies as they are rigid. Unless they all have the same frequency, they would not transmit sound except when moved by the eardrum. This is actually a mechanical amplifier, which uses levers.

    More important to your question, the cochlea in the inner ear has a large number of hairlike structures, called cilia. These are of various lengths and will have individual resonances. They are what actually converts the mechanical vibration of the eardrum into electrical signals for transmission along the otic nerve to the brain. If these cilia are damaged, they will no longer make the conversion and the ear will lose the ability to hear a specific frequency.

    In most cases of hearing loss due to loud noises, the high frequencies are most affected.
     
  3. Ron Shaw

    Ron Shaw Stunt Coordinator

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    The ear is most sensitive in the 'midrange frequencies', and the maximum sensitivity is centered around 1kHz. I'm sure the various mechanisms have individual resonances, but lumping them all together may be difficult, as far as trying to find a single resonance.

    I have seen charts which show various safe listening levels/vs. time, but dont have this info handy now. Needless to say, the higher the SPL, the shorter the safe exposure time is. If you are in an environment which leaves your ears 'ringing', then you have had too long exposure to that sound level. Rock concerts are a good example. I fear the younger genration today, who find it 'cool' to rattle windows a block away with their car stereos, are going to have a quiet and musicless life in the coming years. Lossing your hearing to something so meaningless is...silly, sad, stupid? You fill in the blank.
     
  4. DannyL

    DannyL Stunt Coordinator

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    resonance of the external auditory canal is 3000 Hz, of the middle ear is 800 Hz, tympanic membrane 800-1600 Hz, and the ossicles between 500-2000Hz.
     
  5. Greg Monfort

    Greg Monfort Supporting Actor

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