Funny audiologists only test up to 8Khz.
I know my audiologist tests up past that. Like I said they changed the software that the hospital system uses and now I can not see any lab results or test results before that change over. My Doctor can see them all if in the network and I could go to records and pay $12 for a hard copy but that is a waste of time. I know for a fact that my results went well past 8khz. On more than one instance online Ihave shared my lab's or other information minus my name, date of birth, SS# etc....
You can also test yourself with your phone or your PC and even trash pair of headphones. You can use a signal generator and your home stereo system. There are so many ways to do your own test.
My noise canceling ear buds likewise test your hearing from top to bottom of human range and a little beyound on their app if you want it. It then custom eq's the music so you can get more enjoyment out of it boosting the volume where it can to try and match reproduction to your hearing.
I can also tell you my 1st Class Flight Physical does tests I have never had any other Doctor or Optometrist perform. The eye exam is off the chart the audio exam is very average.
I can also say that my dad's audiologist and the VA also went way beyound 8khz.
That might well be the standard though I am not sure. You could listen to human speech and operate just fine as a human being with hearing up to 8khz and not miss much. Most of the audiblity of speech happens well bellow 8khz. A lot of 2way radio like CB and Commerical Business radio are 350hz to 3000khz and often they will narrow that down even more and even hit it with symetra(sp) type early broadcast asymetry phase rotation then downward expansion and compression which destroys sound quality from an audiophile musicality stand point but makes speech pop out nicely depending on how heavy handed your get. I have one system designed for use of Single Side Band aka SSB that narrows things down to about 800mhz-2000mhz converts the audio to rf for the clipping,compression, DSP and then converts back to audio before injection back into the radio that can break through a contest pile up's like mad. So strictly speeking you do not need a large bandwidth to carry speech data well for intelligibility. The data needs to be clear, concise, uninterupted and the brain has to process it well. In fact someones inner ear can be absolutely perfect and degradations in the brain will be the limiting factor for understanding words and the standard audiology test does not account for which thing is degrading ones hearing it is only measuring the total response or results fromt he test.
If we turn our attention away for a moment frm hearing to eye sight for instance the brains inpact of interpreting what we think we are seeing or not seeing is far better understood. For instance we know that peripheral vision declines with age. We also know that brain training to improve general cognitive function has the happy side affect of improving/restoring peripheal vision.
The way our hearing actualy works compared to how people think it works is not well understood by 99% of the population and doctors do not help because they are always dumbing things down for patients and marketers and public schools do not help either. Not that it matters much since once it is gone it seldom returns. Putting it down to just loud noises is an easy out because that is obvious and the most likely since so few wear hearing protection unless forced to by their work place. Given the insane degradation of systemic health across all systems in the body in the USA since about 1950 until currently though and the insane increase in metabolic and neuroligic dissease in the USA I think it is overly simplistic to put down hearing loss especialy as one ages to just over exposure to loud noises.
If you Google " Freq. range that carries the most speech intiligibility" you will get the follow:
2 kHz-4 kHz
More specifically, in the
2 kHz-4 kHz frequency range. We perceive the voice as natural and with the highest intelligibility when we are approximately 1 meter in front of the person talking.
So that begs the question why would someone that once had 20hz-20,000hz range have issues with speech inteliligibility if their current hearing is far better than this limited range? Either the data the ear is sending is not getting to the brain in a consistent and coherent manner aka nerve conduction issues or the brain is not processing the data properly!
Do note that I am talking about speech not musical apprecation that is another ball of wax. People that have a hard time understanding speech in a room full of people talking or other background noise often have ZERO problem listening to music and having a fantastic experince the two do not always walk the same path! That is why the "why" is important. If ones hearing is degraded across the board that is one thing but if it is just speech that is the problem and only when their is a noisy environment again the "why" matters!
Keep in mind that concusive head trama can affect hearing as well and is one of the possible causes on sensorineural hearing loss hearing loss! Antibiotics can permenetly damage hearing as can viruses! Yes 90% is attributed to over exposure to loud noises but that is not the only way damage occurs!
