Head-Fi.org › Forums › Equipment Forums › Sound Science › hypersonic effect discussion
New Posts  All Forums:Forum Nav:

hypersonic effect discussion - Page 2

post #16 of 111
Thread Starter 

 

Quote:
Originally Posted by gregorio View Post

Quote:
Originally Posted by khaos974 View Post

Suppose that you all a panel of listeners all incapable of hearing beyond 20 kHz, they could still pass an ABX test with the following 2 signals: nothing and plenty of ultrasonic content.
There could be plenty of inter modulation distortion that is below 20 kHz, and that would be equipment related issues.

So in other words a panel of adult human beings! Yes, they could pass the test but you would not be testing for the ability to hear ultrasonic content, you would be testing for the ability to hear distortion within the hearing range of 20Hz to 20kHz!

Kiteki:- The Oohashi study has become infamous and a real pain in the audio world. When it became apparent that the Oohashi experiment produced non-repeatable results (a basic criteria for scientific evidence) it's methodology was examined and found to be severely lacking in several areas. Due to these facts and the large amount of evidence (repeatable) the Oohashi paper, it has been discredited. The Boyt paper you linked to did not provide any evidence of hearing beyond 20kHz. With regard to hearing Boyt just referenced the Oohashi paper, Boyt's paper was written before Oohashi's paper have been discredited.

To date there exists no reliable scientific evidence that humans can hear beyond 20kHz but a substantial body of scientific evidence exists which indicates that we can't.

G


In red,

I am looking for where his study has been repeated, and can't find one, well I'm not fully clear on if it's only Ooohashis study, but I'm talking about this one http://jn.physiology.org/content/83/6/3548.full#aff-1

I don't consider an ABX test "repeating" that study at all, and until I find a repeated study, then why should I believe it's been repeated? I agree with you a scientific truth should be repeatable but as far as I can see it hasn't been repeated, I repeat!! =p

 

 

In blue,

I know the boyt paper doesn't provide evidence for hearing beyond 20kHz, it just shows that instruments resonate that high, that's all.


In purple,

There is a substantial evidence that we can't hear beyond 21kHz, but the supporters of the hypersonic effect agree on this, and they claim that the tests do not show results through the normal air conducting pathways, but rather through something else, and even people with a hearing impairment showed a reaction to the hypersonic frequencies.

 

 

 

 

 

post #17 of 111
Hi Kiteki,

That study you linked to is the Oohashi study, look at the first name at the top of the page. I'm sorry it's a good six years ago that I researched this area and I can't remember exactly who or where they recreated the Oohashi's study. Hopefully someone else reading this can point you in the right direction.

It's pretty much accepted by the pro-audio community that freqs > 20kHz for music are pointless. As I said in my first post, it is possible to perceive ultrasonic freqs, if they are loud enough. The problem is that the higher than 20kHz harmonics produced by musical instruments/voice are not loud enough. For the voice and the vast majority of instruments significantly less than 2% of the energy is above 20kHz, an area of the audio spectrum where at best (according to those who believe in perceiving >20kHz) we are highly insensitive and at worst, we are completely insensitive. Also, the vast majority of studio microphones cannot record above 20kHz and most speakers and studio monitors do not reproduce anything above 20kHz. Not to mention the fact that as a producer, I really don't want to be trying to mix and produce frequencies which I can't even hear! So as an audio professional, the case in my opinion is closed.

G
post #18 of 111
Thread Starter 

Well thanks for your opinion and take on the matter... that's what I want this thread to be about.

post #19 of 111

Try these for Oohashi follow-ups

 

Ashihara et al., “Detection threshold for tones about 22 kHz”, 110th AES convention 2001, preprint no. 5401

Ashihara “Hearing thresholds for pure tones above 16 kHz”, The Journal of the Acoustical Society of America 2007, Volume 122, Issue 3, pp. EL52-EL57

in short Ashihara and colleagues could not replicate the Oohashi results and posited the effect was due to IMD due to the arrangement of transducers used (as per the NHK study you cited) , JVC research back in the late 70s used hard cut-offs at 20K, 18K , 16K and 14K - none of the subjects reliaby detected the 20K cut-off

 

in OoHashi the above 20K stimulae (alone) went undetected - only the combination of below and above was detected suggesting an interference effect - although Meyer and Moran do not address the issue directly their high-res degrading stage also takes out information above 22K again with no strong evidence to suggest it was relevant

 

70s - 00s research also suggests that exposure to inaudible high frequency sounds (in specific industrial settings) at high levels may cause nausea and vomiting

 

post #20 of 111
Thread Starter 

I bought an SACD player,

 

 

to vomit.

post #21 of 111
Quote:
Originally Posted by kiteki View Post

I bought an SACD player,

to vomit.


biggrin.gif

Seriously though you did not waste your money. Most SACD recordings sound better than most CD equivalents. Audiophiles jump on this as proof that we can hear the increased resolution of the SACD format or frequencies higher than 20kHz. I'm not sure if this is due to commercial concerns or just ignorance, probably a combination of both. However the real explanation is a far more simple, economic one:

Record companies know that people who buy SACDs take their listening very seriously as to play an SACD requires an SACD player and they are not cheap compared to mass produced CD players. Therefore when an SACD is recorded they pay the extra to have it recorded by top professionals, in top quality studios and mastered by top mastering engineers. This costs a premium and is why SACDs are expensive, more expensive than the general public would pay for a CD but a price audiophiles are willing to pay for quality. SACDs sound better because what is recorded on them is better, not because the format itself is superior to CD. The sad truth is that you could make a CD sound just as good as an SACD but economically it virtually never makes sense to do so.

So your investment was worthwhile because it allows you to listen to the highest achievements in contemporary recording and mastering.

G
Edited by gregorio - 8/24/11 at 12:40pm
post #22 of 111
Thread Starter 

vomit-1.gif

post #23 of 111
Just in case Nick did not provide you with enough try this:

http://www.head-fi.org/t/266217/from-cd-to-sacd-how-much-of-difference/156#post_3516735

Best debunking of the Oohashi paper I've ever read.

G
post #24 of 111
Thread Starter 

Gregorio, I understand that as an audio professional you want to concentrate on the 20Hz - 20kHz range, I really do get that, that's what music and audio is, but from the Boyt paper I can clearly see that a cymbal crash for instance resonates much higher than 20kHz and with a reasonable amount of volume, I understand our ears aren't tuned to that frequency response way up there, but for the sake of fidelity I'm not sure why we should be ignoring it? I mean it's a bit like comparing 256kbps AAC and FLAC.

 

 

From the hciman77 post you linked to, here's a couple excerpts I found interesting.

 

"5) Oohashi designed the super-tweeter, a commercially available product and this gives him another interest in the outcome of the study, see conflict of interest."

 

That's true, he had a conflict of interest, I don't think he was testing for the sake of testing, I think he was after some kind of result, so I can see that.

 

"2) The graphs are pretty poor but if you zoom in on them you find that the HCS and FRS sound spectrograms are not quite the same below 20K, thus the test is invalid to start with."

 

I don't understand that part, it doesn't look like a subtle change the graphs, it looks like a dramatic change, which makes hciman77's post seem cynical, to me.

 

moving on...

 

"6) Clearly the high frequency sound + normal sound, if we can trust the results has a physiological affect, but it isnt in the auditory cortex, it is in the occipital lobe and that houses most of the visual cortex, processing visual signals. Also the effect is to increase alpha wave activity. Increasing alpha wave activity actually results in relaxation. Thus the sound plus hypersonic sound is causing a relaxation response. So the subjects relax more, this means that they are inevitably going to ascribe positive attributes to this stimulus, note also which ones 5/10 are affected, these are entirely predictable. Thus what we have here is pretty much a smoke and mirrors job and nothing to do with hearing."

So what was this highly relaxing visual stimuli then? or is he saying the the hypersonic sound+audible sound is causing a relaxation response through the optic nerve? (or something similiar), because that is still a very valid finding! It would also perhaps be in favour of the recent (2011) claims from that Japanese company that Jude talked about, that say hypersonic frequency response is diminished, when you cover your face. Even Oohashi supported this, as he noted the hypersonic effect can not be achieved with headphones.

 

Again, after this hciman77 moves on the meyer on moran paper, claiming it did 500+ tests and so on, again I don't see that test as a valid replication so they could have done 5,000,000 tests for all I care, without scientific statistical evidence, if all they're doing is verbally asking the particants which recording was which.

 

 


 

post #25 of 111
The way I interpreted that point is that Oohashi was reporting a hypersonic effect + audible sound causing alpha waves (relaxation effect) in the area of the brain which deals with visual processing rather than with aural processing. Therefore even if there was a response to high frequency (which the poster says there is absolutely no evidence for) it wasn't related to hearing but to sight. This is just more circumstantial evidence that the whole paper is BS, maybe deliberately so.

The reason it's not a valid finding is because of point two, that there was a difference in what the test subjects were hearing within the hearing range.

The reason Oohashi stated the effect cannot be achieved with headphones was covered in point 9.

Mayer and Moran did not ask subjects to identify which was which, just to identify if there were any differences or if they were all identical.

With regards to fidelity, I see no difference in fidelity to the ear being unable to respond to ultrasonic frequencies present in a concert hall to the ear being unable to respond to ultrasonic frequencies which aren't there. It's a bit like the old joke: Customer: "Can I have a coffee without cream please". Waiter: "Sorry we don't have any cream, will you take it without milk?" The only thing we have to be careful of is to make sure the removal of any ultrasonic content in the recording chain doesn't affect the frequency band which we can perceive.

G
Edited by gregorio - 8/26/11 at 11:32am
post #26 of 111

This is a little thing I'm going to throw out here.  I did this a couple years ago, but it does fit this topic nicely.  Please note these are just observations, I say this a later and this won't prove or disprove the fact that we can hear > 20000Hz sounds.

 

I was at my friends house (name won't be mentioned for privacy reasons, let's call him John) and he has a dog.  I thought it'd be cool to test the dog whistle apps on the App Store with the iPod Touch 2G.  So I downloaded one.  Set it to 22000 Hz (>= 2k above our hearing range).  I range it...  The dog looked straight up.  I did it again, the dog looked up again, John gave a quick glance at me (I was looking at the television and he had no clue I was doing this).  I ring it again, this time more interested in his response, the dog had gone into the basement.  When I rang it he squinted as if he heard something  and looked slightly left then slightly right.  I stopped the noise and he had the look of utter confusion on his face.  Please note that at this time, he still had no idea what I was doing (kinda' mean of me, yes; but fun nonetheless).  I did it once more and he had the same reaction, he said that he thought he heard something...  I don't think he heard something, more that his brain interpreted something (a 22000Hz sound wave) as something else. 

 

Furthermore, I would also like to say that I did too also feel a sense of the sound myself as well.  I can't really say I heard it, but I did feel a bit of energy (similar to the feeling you get if you point a laser pointer at your skin, your skin will feel something; energy in a sense) through my ears (similar to the laser pointer on skin).  I did stop though since I started getting a headache from the tone as well (so something must have happened, headaches came and went with the tone).  Now these last few bits may be psychological, but the first bit cannot since John had no clue that the App Store had dog whistles...  I know for a fact that it did make a noise or the dog would not have stormed off like that. 

 

This was done a couple years ago, I was 18 and John was 19 (just in case fresher ears can play a role in this). 

 

What I am providing is straight data (observations if you wish to call it that; observations is still data) from something I did while bored.  I was quite shocked that he was able to actually hear that (I italicize hear for a reason), and that I cold interpret it in some sort of way (again, my side might be psychological, but John's can't be since he had no clue what I was doing).  This data doesn't prove, or disprove, anything since I did not type it in that format.  I do not know the reason either of us felt a sensation from the 22000Hz sound (mine may be psychological, John's cannot be). 

 

Other notes about re-testing this:

  • If there is a fan, or other droning constant sound (or close to constant sound around), you will not be able to interpret the sound (22000Hz tone) since it will be drowned out and mix with that sound.
  • If it gives you a headache, STOP doing it!
  • I'm not responsible if anything gets damaged in the process (this includes hardware, or yourself).

 

_____

 

I just wanted to put this out there as I did find it interesting, it was something I did a while ago, but do remember vividly due to the observations I saw when doing it.  Again this is just data, and no explanation has been formed for why the observations happened.  Do as you wish with it.


Edited by tinyman392 - 8/26/11 at 12:38pm
post #27 of 111
Interesting. My guess (and it is just a guess) is that there was some distortion, filter ringing or some other artefact occurring a little lower in the frequency range. Only way to know for sure would be to put a scope on the iPod, run the dog whistle program again and measure the output.

When I was a lecturer I used to test my classes, about 100 students a year for 5 years, they were all over 16 and mostly 18-21, most max'ed out around 16-17kHz, once found one who could hear 18kHz. There have been reports of the occasional rare case who could hear up to 22kHz, although they were usually young children. That is why 22kHz is sometimes listed as the extreme limit of human hearing and why it is the limit of what can be captured by CD. So, I'm not saying it's absolutely impossible your friend heard 22kHz, just extremely unlikely. I would certainly be looking to exclude other possibilities before jumping to conclusions. I'm sure your local university would be interested in running some tests (given the possibility of finding an adult who can hear 22kHz), might be worth a call if your friend feels like it.

G
Edited by gregorio - 8/26/11 at 2:51pm
post #28 of 111
Thread Starter 

I haven't had time to read the above posts in detail yet, but I just wanted to point out this hypersonic effect is not a "case closed and burned" topic.

 

As you might have noticed, there is this company now called TAKET, which is receiving positive reviews and apparently has made one of the best headphones in the world, at least it is being compared to the best headphones in the world, so they are not a scam, they are making the highest-end audio products.

 

They support the hypersonic effect (they even have super-tweeters built into their headphones) and they are selling this product which is being advertised avidly on head-fi in banners... http://www.taket.jp/bpp/bpp_e.html

 

 

Edit: I'm not saying if it works or not, just saying the topic is still under fire, in 2011. ;)

 

 


Edited by kiteki - 8/26/11 at 9:37pm
post #29 of 111
Kiteki, there is a great deal of reliable evidence against the possibility of perceiving ultrasonic frequencies and none for it. Is the case closed, pretty much yes, there is more chance of me being killer by a meteor than of the human population being able to hear ultrasonic frequencies. Of course there is a chance of me being killed by a meteorite and I'm only willing to say that I'm 99.999999999999% certain that we can't as a race perceive ultrasonics (at normal listening levels). One day in a million years maybe we'll develop the ability or maybe there is the odd human already alive with a genetic mutation but as a race we cannot hear above about 20kHz and for the vast majority of us considerably lower than that.

This type of product, the BPP, is just taking advantage of the fact there is a lot of mis-information and mis-understanding out there. It's so very easy to prove it cannot work (except by placebo effect). The instructions say to plug it into a CD player. OK, CD's are restricted to 44.1kHz sampling frequency, which means ALL content above 22kHz has been removed from the CD. So whether you can hear above 22kHz or not is moot because you can't hear what isn't there (except by placebo effect). Once removed there is no way on earth for removed frequencies to be recovered. So the only thing this BPP can be doing is adding distortion. So why is it getting good reviews? Can only be one of three reasons: 1. The reviewer likes the distortion. 2. The reviewer is suffering from Placebo Effect. 3. The reviewer has something to gain by providing a good review.

Unfortunately, there are a lot of products available to the audio consumer which sell on the basis of marketing mis-information. People and reviewers are paid (or incentivised) to be "shills" and profits are made. Look at the whole area of so called high-end audio cables. These products are no better than far cheaper alternatives and sometimes (for example the audio formats of 24/192 or 24/384) these products are actually worse than the alternatives. The sad truth is that people and companies will make and say anything to make a profit at your expense.

G
Edited by gregorio - 8/27/11 at 5:51am
post #30 of 111
Thread Starter 

Yes,

 

I too don't like incentivised (nice word btw) reviews, or shilling...

 

I also don't like expensive cables, that don't do anything.

 

We live in a time of supply and demand, and if you are supplying tap water for $900, and there is a demand for it, there is nothing wrong with that businessman, it sucks.

 

 

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Sound Science
Head-Fi.org › Forums › Equipment Forums › Sound Science › hypersonic effect discussion