hypersonic effect discussion - Page 3

Maybe I should come out with a new product, how about the SWS (Super Woofer Suppository): Simply stick one end into you CD player with the splitter provided and stick the other as far up your rectum as you can. The SWS provides the fullest musical experience possible: Feel the power of the bass all the way down to your bowels, enjoy a musical "tightness" you never imagined existed. If you can't perceive a difference using the SWS we will give you your money back (and you should visit your doctor)!

G

it exists...

 

Whether or not you can hear hypersonic frequencies, there is a reason to make drivers perform at those frequencies. High end loudspeakers have tweeters that can play to 30, 40 or even 50 thousand Hertz not for any magical effect this may have on the listener, but because this means their breakup frequency will also be outside of the realm of normal human hearing guaranteeing that it will not distort in its primary operating frequency range (say, 3KHz to 20KHz).

If speakers breakup or distort in the hearing spectrum I would conclude they are either being driven incorrectly or are broken. There is a potential advantage in maintaining phase coherency by extended range speakers. Simply because they could be designed to filter HF more smoothly.

G
Edited by gregorio - 8/30/11 at 9:44am

When I was in HS, I had an LP from one of the vendors, maybe it was JBL or HK, or someone like that. It was the early 70's. At the time I had the veritable BOSE 901, a Thorens TD125Mk II fitted with the wonderful SME 3009, and a  Shure V15 MK(?), a Dyaco PAT 5 Kit, (and the HK 11 Peramp, but the PAT 5 was clearly better), and the Koss ESP9 electrostatic headphones. Sometimes I used a couple of mono Marantz amps, and sometimes I used the HK Citation Twelve (built from a kit), or a Dynaco. 

 

WIth a bunch of friends in HS, we played a track on the LP of a violin progressively filtered starting at 18K, 16K, 15K, and so on. Even with the lowly Bose 901's, we could easily distinguish when the violin was filtered at each step, to the point that whatever remaining harmonic structure was left, made the violin sound starkly hollow as it reached its fundamental.

 

Sometimes I wonder about some of us who argue so vehemently about limiting FR to 20 - 20K might be in our middle years, yet the preponderance of Head-Fi folks are probably much younger?    

 

BTW, even though my high FR is down significantly now, I can still discern 14K in both ears, thankfully.  

 

 
 

 

I think it's possible that you maybe jumping to conclusions. IMHO, your post highlights the difficulty of testing the perception of sound. The fact is, that it's very difficult to isolate and test what we think we are actually testing and even experienced scientists sometimes get it wrong.

In your test for example there are a few points which, in my opinion, make it unlikely that you perceived what you think you did. 1. LPs are notoriously inaccurate and noisy at high frequencies, 2. Filters are inherently non-linear and produce audible artefacts well inside the pass band and 3. Of the energy produced by all a violin's harmonics, only 0.04% is above 20kHz.

It's virtually impossible to create an analogue filter operating in the hearing spectrum which does not introduce audible artefacts. Even the latest digital technology needs very careful programming and a lot of resources to implement a filter without audible artefacts. We also have to consider that with only 0.04% of a violin's energy being produced above 20kHz, that even with the very best and latest high tech equipment, it's still bordering on the impossible to record this energy above the noise floor of the recording environment and equipment. Let's say for the sake of argument that it is possible, we come to the last and most telling argument: Even if it is possible that someone can hear a signal above 20kHz, hearing a test tone at 20kHz is trivially easy compared to actually differentiating >20kHz signals from the noise floor and which comprise only 0.04% of the sound you are hearing.

G
Edited by gregorio - 9/2/11 at 3:14am

Thanks for your perspectives gregorio. It certainly was nothing so scientific as you allude to; it was only a simple experiment with a bunch of HS kids. I'm not jumping to any conclusions as you suggest. It was only offered in the context of the discussion. 

 

The topic is the effect of hypersonic's on hearing and what we perceive. HIstorically, audio is really not that old, scientifically, or experientially (as it relates to music reproduction), and as far as I'm concerned, it is still an evolving science. We have not solved the perception equation so that we can recreate the full illusion of a live (place-based, living) event. (Maybe the Holodeck will solve that problem.) I believe that is why topics like Hypersonic Effect Discussion are not as cut and dry as we are led to believe. When we slam shut the door using absolute terminology, we stifle the discovery process. And because we are dealing with perception based hobbies like audio and photography, the scientific method helps model some aspects of what we hear through measurements. Beyond that, it's a work in progress, IMHO. 

 

Here's some more fodder to consider, related to ultrasonics:

 

http://www.positive-feedback.com/Issue52/ultrasonic.htm.

 

Granted, it is not a full-blown treatise on the topic, but there are some additional reference links to consider. 

 

 

 

 

 

 

 

I agree that we have been unable to re-create the experience of a live event in a recording. The reason is because much of the experience of a live event cannot be captured in sound waves. Things like expectation, the perception and emotions of being part of an audience, the 360deg 3-D visual experience of the concert venue, etc, etc. All of these things and more contribute to our experience and perception of a live concert and none of them can be captured on an audio recording. What I can say with absolute certainty is that these things do not exist in the ultrasonic frequencies and recording ultrasonic frequencies will not therefore re-create for you the experience of a live event. Many live events have been recorded in high sample rates which capture the ultrasonic frequencies. To the best of my knowledge, in blind tests never has anyone been able to tell these apart from the same recording with the ultrasonic frequencies removed. It may be possible one day to reproduce the experience of a live event. Maybe one day someone will invent a digital interface directly into the brain and be able to transfer an experience but you'll never get this though an audio system. This is a limitation of all past, present and future sound systems, I'm afraid you are going to have to live with it. Looking for the solution in ultrasonic frequencies is futile, a whole new (and as yet undiscovered) technology is required for what you want.

Hypersonic Effect does not exist, except to those who have some sort of ultrasonic product to sell and to those they can convince through marketing.

G
Edited by gregorio - 9/2/11 at 3:43pm

In my opinion, absolutes, black and white, yes/no, go/no-go thinking only discourages discovery and innovation. This is where I respectfully bow out and stick with respected resources, references and personal experiences. 

  

 

 

Quote:

 

No! God damnit we're losing 'em! MEDIC MEDIC get over here now this person needs some shades of gray STAT!

 

There is an effect that hypersonics have upon us... you can't introduce a variable in to a complex system and expect the system to go unchanged in some way... no the real question here is: HOW MUCH does this change the system? Well the current understanding, based upon experiments, is that when the change is physical in nature, it's so minute so as to generally not be consciously perceived.

 

Or at least I think that's how it works : P
 

 

Well there's your problem. You are relying on marketing and personal experiences and misjudging them as respected resources and references.

The problem is that ultrasonic sound is not introduced to the "complex system" of sound perception, it is filtered out by the ear.

G

I believe you need to study psychoacoustics. Dr. Bose led the way at MIT, and has had a very long road... whether or not hypersonics are related or not, is only part of the discovery, but probably not the primary focus. 
 

 

I think you will find that sychoacoustics is the study of the perception of sound. As there have been no reliable tests where anyone could perceive ultrasonic sounds, ultrasonic sound is therefore not related to psychoacoustics, by definition.

BTW, there were studies of psychoacoustics many years before Bose. For example, Fletcher-Munson curves are still a cornerstone of psychoacoustics today and were created by Bell labs in the 1930s.

G
Edited by gregorio - 9/7/11 at 10:25am