hearing tests - where and how?

This is in response to Learsfool: I am not trying to be contentious but presenting what I know. Most posters on audio forums refer to the work of Oohashi and associates and it is about their work I was commenting.

What I do not know is what you believe is scientifically reliable evidence of "hearing" significantly beyond 20KHz and would appreciate a reference or two.

Kal

This article makes for interesting reading, and supports what Kal has been saying:

http://mixonline.com/mag/audio_world_above/

The reference in the article to "High-Frequency Sound Above the Audible Range Affects Brain Electric Activity and Sound Perception" is the Oohashi paper Kal referred to, which can be purchased from the AES here.

Also, I hope that Professor Kal R., Ph.D., won't mind if I mention that he is a long-time faculty member at one of the most prestigious medical institutions in the United States.

Regards,
-- Al

Thanks very much Kal and Al for the info and the link. Sounds to me like the question is very much unanswered. Just because modern technology cannot measure whether we can hear above 20K does not mean that we cannot. I personally would not be so dismissive of the idea as the writer of that article - I don't think it is an unimportant subject, despite the fact we can't prove it anytime soon. Clearly the results were not entirely negative, so more study is warranted.

I have always found it interesting that many proponents of analog, as stated in that article, have argued that digital processing is eliminating important info from the music. I personally have always tended to agree with this - when I listen to a digital recording of my own sound (I am a professional horn player), it seems to be missing overtones compared to the analog tape recordings I used to make of myself back in the day. You could argue that I am just imagining this, or hearing things or whatever, and you might be right, but you might be wrong as well. We can't prove it. I do know that when I play an LP from the "golden age" of orchestral recording and compare it to a digitally remastered version, the latter just doesn't sound the same. I have always thought that this processing away of anything above 20K must have something to do with that, and I didn't read anything in that article to change my mind on that, though there are certainly other things that the processing could be eliminating that would account for the difference as well, I freely admit. Fascinating stuff - I hope that we do know the answer in my lifetime. And Kal, the research referred to in that article took place after the time I read whatever I read back in college, so obviously I am misremembering that someone had scientifically proven it. I am more than happy to take your word for it that there hadn't been any other significant work done on the subject. Whoever I read must have been writing about it only as a theory. Thanks for your patience with me, I very much appreciate it!

Learsfool wrote:
Sounds to me like the question is very much unanswered. Just because modern technology cannot measure whether we can hear above 20K does not mean that we cannot.

First, the technology we have is more than capable but why would you presume that we can hear supersonic frequencies? All the substantial data indicates otherwise. For example, competent electrophysiology demonstrates that auditory nerve fibers respond to frequencies up to approximately 20KHz in healthy young adults but not higher and the technology is capable of resolving whether there are responses to higher frequencies. So, if any such information is not getting in via the auditory nerves, then (1) one must posit that any higher frequency input must be coming in from a non-auditory pathway and (2) one must, consequently, question its role in auditory perception.

I don't think it is an unimportant subject, despite the fact we can't prove it anytime soon.

Sure, it may be important around here but, frankly, we do have all the technology needed for this but it has not captured the interest of the best scientists in the field.

Kal

Kr4 is correct on all points in this discussion. After spending many years in the field of biomedical engineering and having read hundreds of engineering as well as medical journal articles I can attest to the fact that if there is a topic that is unsettled or begs to be investigated then there is research being conducted on the topic and articles published on the research. The nature of research in these fields is that repeated studies are carried out by different researchers, not only to investigate previously researched questions but also to validate (or invalidate) the results of already published research studies. A single study, without verification, says little. As it is universally accepted that the upper frequency limit of human hearing is 20kHz (look in any physiology textbook) the burden lies with those who assert that the upper limit is higher. A trip to your local enginneering and medical college libraries will provide you with the resources to conduct literature searches of published research necessary to support your theory. Many public universities provide access and assistance to members of the community.