We may need MRI scan after all - audio nervosa

[kittykat]

Also, unlike CD, SACD had a major competing "hi-res" format (DVD-Audio) to contend with.

And you’re right EricW. Consumers were probably pretty confused by then. Interesting to note that Meridian bet pretty big on DVD-A and now they are again on the front line with Sooloos?

There was an interesting article in Rolling Stones recently about how decreasing software prices makes a considerable positive impact on cd sales. On the way in this morning, I saw 4 CD’s for AUD$30. Mostly old classic rock i think and reasonably recent contemporary. Imho think this is a better way to claw back sales than fight some pimply highly driven (by peer acceptance and ultimately a status beyond the sums spent on countering duplication ) computer geek who sleeps 3 hours a day banging at his keyboard.

[STHLS5]

Oohashi wasn't trying to prove the participants could tell the difference. He was analyzing how brain reacts to hypersonic. In all the links debunking Oohashi I don't see results of EEG or MRI scan disproving Oohashi. Whether Oohashi was right or not is not going to change how and what equipments I use to listen. The papers worth a discussion in HUG irrespective who sponsored, conducted or what the motives were. Did any of current results explicitly repeated Oohashi experiment? In my country, I can't even dream of someone repeating his experiment for next 10 years simply because we do not have the facilities nor the expertise. I would at least read the papers in full before dismissing them as SACD marketing. You can also refer to Wikipedia to see rebuttals but nothing shows anyone ever came close nor attempted to see how the brain really function irrespective whether you can tell the difference or not.

The said experiment was more interested to find out the effects of frequencies above human hearing threshold which 20khz. But it is also common for most of us couldn't hear anything above 14khz at normal listening level. So would our brain react similarly with or without musical content above 14khz.? Could we subconsciously react to frequencies outside those can be detected by our ears?

ST

[A.S.]

...But it is also common for most of us couldn't hear anything above 14kHz at normal listening level. So would our brain react similarly with or without musical content above 14khz.? Could we subconsciously react to frequencies outside those can be detected by our ears?...ST

If we respond to super-high frequencies then what organ of sense are we detecting them up with?

I recall our founder, Dudley Harwood explaining that above about 3kHz (i.e. around the frequency at which the tweeter starts to contribute) the ear is not 'fast' enough to follow the up and down shape of the waveform of the frequency as you'd see it drawn out on an oscilloscope. That's because our nervous system is a chemical-electrical transfer; one cell changes it's chemistry which then bumps a minute voltage along to the adjacent one and so on right along the nerve. It is an extremely slow process sending an electrical signal along a nerve. So slow, that fast-moving signals (i.e. high frequency signals with a short period) just can't be transmitted reliably - they have come and gone before they can be shunted along the nerve.

So, there must be a substantial amount of processing in the brain of higher frequencies, or rather, there must be clues in the overall sound energy 'package' at any one instant that allow the brain to work-around the slow nerve transfer by filling-in or guessing the fast details that can't be sent along the nerve. That process is in action down at 3kHz - it's hard to imagine what could possibly be happening at ten times (30kHz) or thirty times (100kHz) that frequency. It's very hard indeed to believe that anything worthwhile is dribbling out of the end of the nerve fibre at those vastly elevated frequencies, hence, nothing useful for the brain to work on. The same situation discovered by the transatlantic telephone cable pioneers - no matter how much high frequency was pumped-in, no top arrived at the other end.

Let's not forget evolution. Our auditory system, developed over about twenty million years, was developed for one and one reason alone; survival and the detection of predators. One of the most dangerous sounds we could hear (in the jungle) would have been a twig snapping indication perhaps an approaching threat. That sound is clearly detected with an energy peak around 3kHz - not 30kHz or 100kHz. Nature is efficient and not wasteful. If we needed to hear to super-high frequencies for survival, all humans devoid of super-high frequency hearing would have been eaten by predators.

Our ears were not optimised for music (a very recent invention), nor really for speech. And that's why they have a usable frequency bandwidth that perfectly adequate for survival, far more than is needed for speech and more than adequate for musical pitch.

[STHLS5]

If we respond to super-high frequencies then what organ of sense are we detecting them up with?

According to Martin Collom advance notice has now been given of further work by Oohashi which suggests that his previously reported phenomenon actually requires that the body and not just the ears be exposed to the ultrasonic sound field. If the body shielded from the ultrasonic component, then the perception of an extended bandwidth is no longer reported.

ST

[A.S.]

That must be the naked body then. Clothing would (does) readily absorb high frequencies even in the middle of the audio band.

I was thinking about the comment that in the rain forest 'there are frequencies up to 100kHz'. In fact, a rain forest, especially when raining, would (probably) sound rather like hiss, the inter-station static on a VHF radio or a crackly record's run-out groove. In other words, a completely random wide-band noise. Is that relevant to speech or music in ordinary life? No. Would evolution have deliberately extended our hearing to catch all of these super-super high frequencies? No. The problem from a survival perspective is that if the hearing range is too extended, then we are unable to hear the predators because our hearing would be drowned-out with useless random noise from the wind rustling leaves and other HF details.

As I said, evolution is very frugal; we are neither provided with super senses nor inadequate ones. The senses we have are exactly right for the environment in which we live. No more, no less.

[kittykat]

If we respond to super-high frequencies then what organ of sense are we detecting them up with?

my hypotheses is the "ears", not as we imagine it, but still the ossicles and the bones in the middle ear. the reason for saying this is because those in the aviation industry shield not only what we commonly know as the "ears" and the entrance (with ear muffs and plugs) but are encouraged to put their hands to shield the part behind the ear as well., where the temple is. The ossicles (although in the "middle" ear is actually very closed to the surface). You'll see the aircraft carrier deck guys doing it (fingers pointing back v shaped, elbows 90 degrees). Ignoring protection of this area can apparently be equally dangerous. Looking through some of the documents last night, think i read more than once that a certain bone being mentioned and ive heard people in the maintenance industry also mention this. Must be more than a coincidence.

Any specialist in this area like to confirm?

If we move away from a music and sound perception perspective (as we know it), there is little if no doubt that very low (or in this case high frequencies) having physiological effects. Ultralow sonic wave generators are already being used as a weapon, even in the fight for whales. can't remember which party uses it but yeah, its being used in the southern oceans and it can really disorientate a human.

[STHLS5]

As I said, evolution is very frugal; we are neither provided with super senses nor inadequate ones. The senses we have are exactly right for the environment in which we live. No more, no less.

You have often emphasized that our auditory senses are for survival. But unlike other life form human evolved beyond surviving. If survival alone our predisposition in evolution, we would not be using fire to cook our food nor wearing any clothes. Unlike other animals we discovered music and musical instruments. Leaving that aside, why didn't our auditory senses evolved despite being exposed to music more than 35000(?) years. Evolution doesn't stop or does it?

ST
p.s New research about auditory memories published on 27May2010 is here. I will post later to the other thread after reading it.

[honmanm]

Alan, I'm not sure of the evolutionary argument for the irrelevance of frequencies above 20kHz.

Have a look at hearing ranges of assorted non-primates here and some monkeys here and deer here.

It seems that 40kHz is quite a common upper limit for smallish animals that would be typical prey.

In Eugene Marais' "Soul of the ape" (I think) he commented that normally baboons have much greater visual and auditory acuity than humans, however when hypnotised the human subjects' abilities were on a par with the baboons. While his studies were not what we would consider to be scientifically peer-reviewed and did not touch on frequency range, his book has left the lingering thought that maybe he was right and that what makes people uniquely human is the suppression of our instincts. That doesn't really help with the present discussion, though...

[A.S.]

You have often emphasized that our auditory senses are for survival. ...why didn't our auditory senses evolved despite being exposed to music more than 35000(?) years. Evolution doesn't stop or does it?

I stress it because there is a total correlation between evolution (Natural Selection) and the senses we have today. Not only senses, but every aspect of our physiology and our interaction with others is deeply rooted in our evolutionary development. Just tour the nightlife district of any city and you'll see primative evolutionary forces cloaked in a veneer of 'modern man'. We are entirely the product of evolution - regrettably there is no escape from that, for good or ill.

I've mentioned before that 35,000 years back (to the first musical instruments) in evolutionary development is a mere click of the fingers. It is as if it were yesterday.

Some maths .... let's say the first recognisable man evolved 3.5 million years ago. 35,000 years in a time line of 3.5 million years represents only 1%; so musical instruments represents merely 1% of our exposure to evolution as a recognisable human-like form. That is not long enough for the environment to have made any preferential selection amongst and in favour of those with super-hearing.

We can go further back and say that our hearing system is probably virtually identical to adapids such as Darwinus masillae, back about 37 million years. 35,000 years in a time scale of 37 million years means musical instruments represents only about 0.1% of our total development. Hence, music is an evolutionary irrelevance in physiological terms.

[yeecn]

The discussion is getting very interesting indeed. I personally would like to keep an open mind on this subject. I don't think the human ear and the central nervous system can receive the hyersonic sound as a type of signal that the mind can interpret (as music or other information) and make consciously use of. But the human body is basically an electro-chemical system. So it is possible that the high frequency sound can be absorbed by the various glans or organs and produce observable (and potentially beneficial) effects.

The criticisms on Oohashi experiment was on his methodology and his conclusions. Nobody is trying to disprove him. The NHK experiment was actually trying to repeat his experiment using more stringent methodology, and they cannot reach the same conclusions. So the result is inconclusive at present.

In the mean time - the audiophile enthusiasts are quoting Oohashi experiments to make claims of how adding a super tweeter 'improved' the sound of their systems. Those claims are especially ridiculous when most of these enthusiasts are only listening to CD - which has no output whatsoever above 20kHz.

[A.S.]

... But the human body is basically an electro-chemical system. So it is possible that the high frequency sound can be absorbed by the various glans or organs...

That sounds OK at first, but we know that the skin is reflective at audio frequencies and only up in the infra-red range is absorptive, where the wavelength is very short and can penetrate the skin - hence sunburn.

If the high audio frequencies bounce off the skin, which organ or organs are detecting them?

We know that even the very thin and porous grille cloth can and does effect the tweeter output at even 15kHz, and would have huge effect at 30kHz. A shirt, with it's completely closed woven structure would pass little through above perhaps 5kHz (a guess), so how a clothed body could be susceptible to super-high frequencies is a complete mystery.

[STHLS5]

.....I've mentioned before that 35,000 years back (to the first musical instruments) in evolutionary development is a mere click of the fingers. It is as if it were yesterday..

Did music really evolve as recent as 35000 years ago? Besides humans animals do make music. They must be doing that for millions of years. Birds sing and some birds go through certain ritual like dancing to court the opposite ***. The oldest flute made of bone is said to be 57000 years (or 35000). For humans to reach the sophistication of making flute must be later, i.e., after basic musical instrument such as drums. Why should humans be exception to the general rule? The oldest stone tool factory is 25000000 years old. Can music to be as old as that or as old as life itself? Humans must have heard birds singing millions of years ago and if they bulit factory millions of years ago then wouldn't they have discovered some sort of musical instrument or at least use their voice to repeat songs of the animals? In fact, the birds singing or other sound by howling wolfs may have exposed human to music millions of years ago. And those sound are without the 22khz CD upper limit.

That sounds OK at first, but we know that the skin is reflective at audio frequencies and only up in the infra-red range is absorptive, where the wavelength is very short and can penetrate the skin - hence sunburn. If the high audio frequencies bounce off the skin, which organ or organs are detecting them?...

Maybe not the skin but how about hair fiber and hair follicle covering our skin and especially our head over the skull covering the whole brain. I am not sure but did anyone research of those possibilities? Insect uses the tiny hairs to detect vibration.

ST

[A.S.]

Ok, I'm no anthropologist. I really can't add anythin more here. Whether the first instrument is 35,000 or 75,000 years ago is irrelevant. In our evolutionary development, music is an extrememely recent development and there has been insufficient time for our DNA to significantly adapt to that in perhaps as few as 1000 generations. An enhanced ability to play or hear music does not seem to have offered any irrisistible attractiveness to a mate, so has not been positively selected by evolution. It's as good as it needs to be.

That's all I have to contribute to this thread.

[STHLS5]

..That's all I have to contribute to this thread.

Thank you very much for your contributions to this thread. It was very informative.

Regards,
ST