driving long distance with ear plugs
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From: Midlothian
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How did i do as a novice audiologist? I am an EE, and am interested in sound in the work I do evaluating high end audio gear, and also in protecting my own hearing. You are right about bone conductivity in terms of hearing - what I did not says as precisely as I should have is that the physical effects of sound on the body can be tiring - imagine being pummelled by a 30 Hz tone at 115 dB for 5 hours. The amount of subsonic noise in a car at levels above 85 dB is substantial by my measurements.
Yes, Fletcher-Munsons's pioneering work has withstood the test of time - some of the best science does that: Maxwell in electromagnetics, for example - he layed it out 150 years ago, and not much has changed, except perhaps if one were to get into the quantum arena in terms of potential E/M effects.
If I read your post correctly, are you saying that it is duration and amplitude only that figure into hearing loss? I thought that a very loud 50Hz wave was much less damaging than a 5 kHz wave, because the tiny hairs are more susceptible to damage - is the reduced loss at low frequencies only because of the filtering?
It is really sad to me that many young people are damaging their hearing, and without a break-through in medical science, that will be for keeps - tinnitus will remind them of what they have lost. I wonder if some of them will ever be exposed to natural acoustic instruments before the damage is done? You young bucks - read about what has happened to Pete Townshend - it is sobering.
I have a set of the Eytomotic in-ear "headphones" that were tailored to the frequency ups and downs of my own hearing - they are absolutely amazing. MY ESL speakers have response into the ultrasonic range, but beam like crazy.
How did i do as a novice audiologist? I am an EE, and am interested in sound in the work I do evaluating high end audio gear, and also in protecting my own hearing. You are right about bone conductivity in terms of hearing - what I did not says as precisely as I should have is that the physical effects of sound on the body can be tiring - imagine being pummelled by a 30 Hz tone at 115 dB for 5 hours. The amount of subsonic noise in a car at levels above 85 dB is substantial by my measurements.
Yes, Fletcher-Munsons's pioneering work has withstood the test of time - some of the best science does that: Maxwell in electromagnetics, for example - he layed it out 150 years ago, and not much has changed, except perhaps if one were to get into the quantum arena in terms of potential E/M effects.
If I read your post correctly, are you saying that it is duration and amplitude only that figure into hearing loss? I thought that a very loud 50Hz wave was much less damaging than a 5 kHz wave, because the tiny hairs are more susceptible to damage - is the reduced loss at low frequencies only because of the filtering?
It is really sad to me that many young people are damaging their hearing, and without a break-through in medical science, that will be for keeps - tinnitus will remind them of what they have lost. I wonder if some of them will ever be exposed to natural acoustic instruments before the damage is done? You young bucks - read about what has happened to Pete Townshend - it is sobering.
I have a set of the Eytomotic in-ear "headphones" that were tailored to the frequency ups and downs of my own hearing - they are absolutely amazing. MY ESL speakers have response into the ultrasonic range, but beam like crazy.
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From: Minneapolis, MN
A few years ago I decided to stop praticing clinically and do research. I'm now two years into my Ph.D. at Vanderbilt my research focus is on the DSP algorithms in Cochlear Implants and Hearing aids. I am finishing up a minor in E.E. this spring. So I can totally understand your love for acoustics and stereophile level equipment. I wouldnt trade my Kimber Kable for anything!
You did a great job of providing an accurate estimation of the auditory reception and localization processes. It was a very clear summation of how the hearing loss occurs as well. One thing that you may find interesting is that the Cillia you referred to are specifically called the "haircells" there are two banks of haircells know as the inner and outer hair cells the outer bank of hair cells are what are first and most often damaged by noise induced hearing loss. I thought this may help you form a mental image of the process.
When looking at noise damaging hearing you are right that there is a correlation to the frequency itself. But the overall bandwidth for possible damage is pretty large, large enough that it would encompass more than just high frequency stimuli. You are correct in saying that a very low frequency sound will be less likely to cause noise induced hearing loss. Part of this is due to cochlear mechanics and the normal hearing curve where sensitivity decreases at these low levels so the intesity would need to be much greater to reach threatening levels. So yes you are correct.
Funny that you mention young people damaging their hearing and resulting tinnitus. My motivation to get into this field was prompted by my current mild hearing loss and nagging tinnitus, as a result of installing car stereos as a teen and contorting into trunks to run wires with countless SPL's pounding my young and stupid head. I have since learned my lesson all too well.
Those Etymotic head phones are great, if you havent heard the processor they make that stimulates an average HRTF ( head related transfer function) its a must try the realism of the simulated acoustic environment over head phones is really impressive. Also Mead Killion who owns Eytimotic is an extremely friendly gentleman who has countless stories to tell and a moustache that you could never forget.
My recent ventures into the world of EE have only shown me how neglected my math background is from years of focusing on pathology and etiology. I am green with envy everytime I hear the professor say something like "This just requires some simple linear algebra" and I sit there thinking... Oh yeah... simple...
You did a great job of providing an accurate estimation of the auditory reception and localization processes. It was a very clear summation of how the hearing loss occurs as well. One thing that you may find interesting is that the Cillia you referred to are specifically called the "haircells" there are two banks of haircells know as the inner and outer hair cells the outer bank of hair cells are what are first and most often damaged by noise induced hearing loss. I thought this may help you form a mental image of the process.
When looking at noise damaging hearing you are right that there is a correlation to the frequency itself. But the overall bandwidth for possible damage is pretty large, large enough that it would encompass more than just high frequency stimuli. You are correct in saying that a very low frequency sound will be less likely to cause noise induced hearing loss. Part of this is due to cochlear mechanics and the normal hearing curve where sensitivity decreases at these low levels so the intesity would need to be much greater to reach threatening levels. So yes you are correct.
Funny that you mention young people damaging their hearing and resulting tinnitus. My motivation to get into this field was prompted by my current mild hearing loss and nagging tinnitus, as a result of installing car stereos as a teen and contorting into trunks to run wires with countless SPL's pounding my young and stupid head. I have since learned my lesson all too well.
Those Etymotic head phones are great, if you havent heard the processor they make that stimulates an average HRTF ( head related transfer function) its a must try the realism of the simulated acoustic environment over head phones is really impressive. Also Mead Killion who owns Eytimotic is an extremely friendly gentleman who has countless stories to tell and a moustache that you could never forget.
My recent ventures into the world of EE have only shown me how neglected my math background is from years of focusing on pathology and etiology. I am green with envy everytime I hear the professor say something like "This just requires some simple linear algebra" and I sit there thinking... Oh yeah... simple...
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s2kbug
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Jul 16, 2002 06:02 PM