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[PookyNMR]

I have tried experiments with mics and speakers capable of upto 32KHz reproduction in conjunction with 96k sample rate (to capture these ultrasonic frequencies).

I am convinced that the audible differences that are being attributed to Ultra High Frequencies that have nothing to do with those fequencies but rather other factors that are within the audible range.

Also with this equipment, the highest frequency any of my test subjects could hear was 24KHz.  After that no matter how loud I played the tones, no one could hear them.   (Most people could not hear >20k - not even really loudly).  

Bottom line is I would have to see some creible evidence to have my mind changed.  To date, I have seen none.

pax

[Terry Demol]

Plectra wrote on Mon, 23 January 2006 20:44

as I said. I'll get some of the research when I'm back in but more importantly test yourself.  We have not had one test subject (and yes this research will also be availible in time, ultra sonic is not actually the main thrust, but essential research for the project)that did not react to the wideband, and 100% (very few out of the subjects were anything like audio engineers) choose the wideband as being the superior recordings.  Tannoy have a basic paper to support their supertweets you'll get that from the site (though it is basic).  the best thing is to go out and get a towshed maximum supertweeter, paired with a earthworks sigma 6.3 (or another good speaker) and TRY IT YOURSELF; you know you have to

Plectra,

You refer to 'we', may I ask who that is?

WRT testing yourself, I'm not sure this is the right approach
here and will probably just lead to more of the arguments that
have happened in the past. Dan is trying to keep this forum
technically/scientifically based and it is fair to respect his
wishes.

However I am interested to hear results of any scientifically
conducted tests that you have done or been involved with that
have verifiable and repeatable results.

Cheers,

Terry

[Plectra]

afraid not -right now.  If you don't want to listen yourself then you really have no interest on the subject, do you?  But, I appreciate the forum rules.

tell you what; when we publish our stuff I put up the relevent bits with results and files for you to decide.  The problem is that most people seem to test for the wrong things and in the wrong way.  We don't use the cochlea at those freqs and so using the 'hearing' test especially in swept sine etc is not the way.  the response though can be conclusively shown (even in subject with very poor hearing) and the difference can be huge when combining this with 20-20 material.

Also this has great uses beyond what most people are thing right now.

we'll have more fun with this later

[Barish]

Plectra wrote on Mon, 23 January 2006 14:57

It is very easy to prove using otoacoustics but more amazingly there was a Japanese study which showed that most test subjects could identify human voice pitched into ultra sonic range through a contact transducer and many could even make out what was being said!

Could you please lead me to the official papers of that study? I would like to know what modulation method they used to pitch human voice into ultrasonic range.

If it was an amplitude modulation then I can see how people could hear what was being said. It's like your guitar amplifier picking up AM radio. No matter what the carrier signal is, the audio content is always there with its own waveform and length at the peak points of the carrier waves. Just connect the dots and you have the envelope.

But if it was a frequency modulation then it would be worth my while investigating it further cos that would mean people really heard ultrasonic range. You never hear a guitar amp picking up FM stations, cos that requires a special discriminator circuit to extract the audio frequency content from a higher frequency range carrier, which neither guitar amplifiers nor human hearing system have.

So I need more detail on that study.

M Ozturk

[Terry Demol]

Plectra wrote on Tue, 24 January 2006 10:47

afraid not -right now.  If you don't want to listen yourself then you really have no interest on the subject, do you?  But, I appreciate the forum rules.

Now just slow down a bit there sunshine!

I listen to high FS playback regularly and I am very interested
in the subject.

Hence my polite question, if you did have some scientifically
done tests that can shed some light on the subject I would be
interested to see the results or some test methodology.

That's pretty clear and is in alignment with Dan's wishes
of keeping discussion here technical / scientific.

Cheers,

Terry

[PookyNMR]

Terry Demol wrote on Tue, 24 January 2006 05:57

Hence my polite question, if you did have some scientifically done tests that can shed some light on the subject I would be interested to see the results or some test methodology.

I, politely, second this motion.  If there is evidence, let's see it.  Talk is cheap.  

[danlavry]

Plectra wrote on Tue, 24 January 2006 10:47

afraid not -right now.  If you don't want to listen yourself then you really have no interest on the subject, do you?  But, I appreciate the forum rules. tell you what; when we publish our stuff I put up the relevent bits with results and files for you to decide.  The problem is that most people seem to test for the wrong things and in the wrong way.  We don't use the cochlea at those freqs and so using the 'hearing' test especially in swept sine etc is not the way.  the response though can be conclusively shown (even in subject with very poor hearing) and the difference can be huge when combining this with 20-20 material. Also this has great uses beyond what most people are thing right now. we'll have more fun with this later

1. Terry asked you to say who is "WE" and so far you did not.

2. That old research from Japan (about 10 year ago if I recall) is very questionable, because some attempts to recreate it failed.

3. That research conclutions was that we can react to some sub 30KHz energy. Well, at the time it was published, I did not wish to question it so I designed a 88.2-96KHz converters which yield plenty margin for 30KHz. But some in the industry wated to go to 192KHz, based on thin air.

4. Anyone can claim anything, especialy when they say "stay tune and we will publish stuff in the future". That is the sort of argument that would serve as a basis for selling sugar water to cure all sickness. So until such time that you DO have published material, that can be CONSITENTLY REPEATED BY OTHERS, ethics sugests that you hold your piece...

Regards
Dan Lavry
www.lavryengineering.com