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'deaf' above 14kHz, appear to hear above that frequency -- hypothesis as to how.


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42 minutes ago, John Dyson said:

Here is an interesting datapoint.   This is about HF hearing, not about the software that I am working on...

 

I don't know what this means, but before making any assertions -- my hearing is blind to tones > 14kHz.

Note exactly the language that I am using -- 'blind to tones',  not cannot hear >14kHz!!!

 

During testing, I found that I made a mistake on one of the equalizers in my SW -- caught by hearing an anomaly in the sound...

I was wrongly using an equalizer that is an HF shelving filter of 21kHz with a rolloff of -3dB.  (Yes, such small details are important.)

Instead, I should have used 18kHz, with a gain of 18kHz/21kHz.or -1.34dB.  (  I happened to choose the  wrong

filter spec because I was not thinking clearly, and should have chosen the 18kHz EQ to begin with...)

 

Even though when considering the normal hearing rolling off at 18-20kHz, and my hearing rolling off at 14kHz, I could hear a profound difference

between the 18kHz, -1.34dB 1st order EQ vs. 21kHz, -3dB.   The 21kHz, -3dB rolloff seemed to leave more highs in the sound, but the highs seemed distorted.

These kinds of distortions or 'tells' are why I can do EQ in certain cases in frequency ranges where I cannot hear well. Oddly, this scheme doesn't

appear to work at freq <1kHz or so.)

 

Now -- about this strange HF hearing.   A 1st order EQ of 18kHz, -1.34dB  has a small effect at 14kHz, and even at 14kHz, I my hearing of

tones is more weak than at 10kHz.   The difference that I am hearing is more significant than the sub-dB change that technically is happening

in my normal range of hearing.

 

This is a guess, and for EEs they will understand this hypothesis:   I believe that my hearing, blind at 14kHz is sometimes getting the effect of parametric

amplification, perhaps the nonlinear effects at frequencies above my normal range of hearing.   So, with the co-incedence of energy in the HF region, a kind of parametric amplification

or biasing of my hearing can boost my ability to hear transients above 14kHz.   I don't think that I  can ever hear 'tones' at 18kHz, but I am hearing some kind of

distortion as a result of co-incedental energy.

 

This biasing/parametric effect thing is the REAL reason why analog tape bias works.  It makes me wonder if the same kind of thing is happening, but

with a different result or purpose, for hearing >14kHz?

 

For those into 'measurements' -- this might be an interesting project, and one reason why some 'golden ears' honestly complain about differences when

BTW is wider/narrower than 20kHz, yet most of 'em cannot hear much above 18kHz or even less....   I really don't think that this is much about

'filter skirts', but might be a contributing factor.   Also, there can be issues associated with time delay (e.g. high order analog filters or not-linear

phase digital filters causing time delay differences.)

 

Just an observation -- but also a helpful odd artifact of human hearing (or at least, my own human hearing.)

 

ADD-ON:  I noticed the 'distortion' on processing the Supertramp recordings this morning, but heard it again when processing 'Olivia's' recordings.   I did a review and found the bug described above.  Once the 'bug' was corrected, the distortion went away.

Another ADD-ON:  This has manifest on different headphones & different situations in the past.  I just finally realized that this might be an interesting issue for someone to research.   I am sure that at the levels that we are speaking, this isn't a headphone nonlinearity matter, and I am using high sample rates in the 88.2k/96k range for the ultimate D/A conversion.

 

John, the simplest explanation is that you're just hearing IMD. Energy at or above 14kHz can be significant on some recordings, so you don't need to hear those frequencies, as they add and subtract with frequencies below 14k.

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41 minutes ago, pkane2001 said:

 

John, the simplest explanation is that you're just hearing IMD. Energy at or above 14kHz can be significant on some recordings, so you don't need to hear those frequencies, as they add and subtract with frequencies below 14k.

THANKS FOR THE REMINDER:

 

I thought about IMD also. but that would have to be one heck of a lot of IMD if at 18kHz/21kHz directly in the local analog/digital circuit.   Note that the 'distortion' difference  that I am hearing isn't the result of significant signal level difference either (both EQ result in similar levels), and the energy at those frequencies shouldn't be high enough to cause significant IMD.  I was hearing a PROFOUND amount of distortion -- but read further -- I was reminded of what was really going on.

 

There is ONE thing that it could plausibly be, and it COULD be IMD, but not generated directlty by the signal at 18-21kHz.   There is a vast amount of anti-distortion phasing in the signal procesing on the decoder, and if the phases and cancellation isn't done perfectly, some of the latent distortions left over from the FA signal processing can be let through.   I really doubt that is the source of distortion at the high frequencies in the local circuitry, but could be the modulation products created at the lower frequencies, in the mutiple dynamics processors needed to produce FA and the phasing at the lower frequencies didnt' cancel as completely.

 

So, I didn't initially think about IMD because of the energy levels at 18kHz are so small (not enough to directly create noticeable IMD at lower frequencies), but there IS already a lot of IMD in the FA signal, and the incorrect EQ at 18kHz could cause more profound phase effects at lower frequencies than the effects on levels.  A senior moment where I forgot about an important feature in the decoder that appears to exist nowhere else.

 

The phasing matter has been a major improvement over a straight-forward design with simple EQ.   But, I just didn't think of it in this specific instance (again, transient senior moment)   In fact, the EQ being done at 21kHz and/or 18kHz had the anti-distortion phasing in it also.  This just might have been a senior brain fart about what was really going on.

 

ADD-ON:  explaining where the phasing modulation is happening...   Think about multiple dynamics processors with a dynamically changing phase, but instead f the output of each unit being hand-in-glove decoded, the processing goes further on to another step.   The anti-distortion cancellation does an approx 1st order cancellation of the PM that is happening in the signal.  So, the audible effect is anti-IMD when actually it does significant cancellation of the PM.   This happens at each step in the process.   The major effect of the anti-PM EQ when it comes to frequency response is pretty much nil, but the effect on phase is profound, and along with the anti-MD code, makes a MAJOR improvement for distortion reduction.

 

I should have remembered -- but I get tripped up once in a while, then get locked into wrong-headed thinking for a few days.

 

I REALLY WISH I HAD A CO-WORKER ACROSS THE DESK LIKE I USED TO...   I was a member of a sub-team of two people at AT&T Bell Labs, myself (the crazy person), and the exquisitely sane person who was mildly on the 'spectrum'.   Both of us together created a superhuman, but by myself, I am incredibly mistake prone.  I really love the good old days!!!

 

John

 

 

 

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2 hours ago, pkane2001 said:

John, the simplest explanation is that you're just hearing IMD. Energy at or above 14kHz can be significant on some recordings, so you don't need to hear those frequencies, as they add and subtract with frequencies below 14k.

 

 If this was true , there would be absolutely no point in anything with higher frequency content than 21kHZ such as Professional  reel to reel tape, Vinyl, (which these days can readily exceed >30kHZ,)  SACD , 48kHz of Music Videos, 24/96 and 24/192 and DSD.

 I prefer the sound of 24/48 on Music Video for example over 16/44.1 of the same recording . e.g. The often discussed Olivia Newton John recordings in John's PM group sound better to me than the same on CD, which is why I have linked to them several times previously.

 

It is insulting to the vast majority to members to suggest that their preference for High Res material is imaginary simply because they are no longer directly  able to hear a pure sine wave of >15kHz due to their age demographic.

 Perhaps I must be really stupid to believe that my collection of 6 high res albums ( in 24/192) from SoundKeeper Records sound markedly better than the same recording professionally downsampled to 16/44.1 ? 😜

 

P.S. 

I assisted Barry with the selection of the best sounding out of 4 versions of .aiff to .wav converters for his most recent 24/192 album Kay Sa.

I have since heard the previous 5 albums reconverted using this S/W and they all sound clearly better under non sighted conditions.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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Just now, sandyk said:

 

 If this was true , there would be absolutely no point in anything with higher frequency content than 21kHZ such as Professional  reel to reel tape, Vinyl, (which these days can readily exceed >30kHZ,)  SACD , 48kHz of Music Videos, 24/96 and 24/192 and DSD.

 I prefer the sound of 24/48 on Music Video for example over 16/44.1 of the same recording . e.g. The often discussed Olivia Newton John recordings in John's PM group sound better to me than the same on CD, which is why I have linked to them several times previously.

 

It is insulting to the vast majority to members to suggest that their preference for High Res material is imaginary simply because they are no longer directly  able to hear a pure sine wave of >15kHz due to their age demographic.

 Perhaps I must be really stupid to believe that my collection of 6 high res albums ( in 24/192) from SoundKeeper Records sound markedly better than the same recording professionally downsampled to 16/44.1 ? 😜

 

P.S. 

I assisted Barry with the selection of the best sounding out of 4 versions of .aiff to .wav converters for his most recent 24/192 album Kay Sa.

I have since heard the previous 5 albums reconverted using this S/W and they all sound clearly better under non sighted conditions.

 

I'm guessing it's really hard for you to follow what I say, Alex, and this is not the first time.

 

If you read carefully, I made no claims at all in my post, but you've certainly made a bunch and even accused me of insulting others. Are you feeling ok?

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Hearing is really complex as, along with smell, it is a primary 'survival' sense and is always 'on' and tuned to receive input.

 

While we hear primarily with our ears that's not the only part of our body that senses sound. There are profoundly deaf people that have trained themselves to hear, and even to enjoy music.

 

The reception of sound on the body is also processed by major parts of the brain, and brain/mind functioning is still, to a large extent, a "black box".

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2 minutes ago, pkane2001 said:

I'm guessing it's really hard for you to follow what I say, Alex, and this is not the first time.

 You always come out on the side of measurements to attempt to prove what others report hearing is not due to  their hearing above the thresholds generally quoted for older people. 

 At John's age for example, he shouldn't be able to notice tape hiss either, let alone miniscule amounts of IMD. 

Hearing Loss -Steve Hoffman Forums.jpg

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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(sorry about not properly quoting -- I am a very primitive user of GUI stuff.

 

I still think that there is  the *possibility* of SOMETHING going on about the parametric effects.

I am not fully convinced (NOW, after this recent experience) that there isn't something usefully nonlinear in the auditory process.  My current position is still about the engineering norm right now.

 

An experiment that eliminates the variables, also considering the parametric effects,  SHOULD be done.   Most of the

time, the thinking is limited to simple nonlinearity instead of the more dynamic parametric nonlinearities.

 

However, for now, I am still a believer in the 20kHz orthodoxy.   My mind is open for other things though -- once there is true, more than anecdotal evidence.

 

Parametric amplification usually entails some kind of IMD, but isn't the typical audio IMD, and the output from the desired signal can be greater than the input (given

the amplifier or mixer is pumped by a signal, like tape bias, for example.)

However, I also agree with @pkane2001(in a circumspect way) tabout my issue, hat there are other things that are going on -- I temporarily forgot them.

 

Some day, I'll do some demos after turning off the 'special sauce' entirely.   (The 'special sauce' is a bunch of distortion cancellation stuff.)  The difference is extreme.

The trivial, straightforward EQ sounds significantly worse than the circuitous EQ that I do for the 'sauce.'   The cancellation EQ is substantially different than the norm,

and is a bit non-intuitive. Since the special sauce works so well, I quit using a special switch to disable it, and the mode can only be disabled in legacy parts of the code.

This special EQ makes me think that there MIGHT be equipment that doesn't sound as good as it should -- because the 'trick' isn't well known?   Some actual measurements might also be useful in the future.

 

 

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28 minutes ago, GregWormald said:

While we hear primarily with our ears that's not the only part of our body that senses sound. There are profoundly deaf people that have trained themselves to hear, and even to enjoy music.

 

 Even Archimago has acknowledged that people with severe hearing damage are often able to hear things that others are unable to hear.

 In my case, in addition to me now being 82, I have a 21mm diameter Acoustic Neuroma pressing directly on my right ear canal, yet I prefer well recorded High Res material over the same on RBCD.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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5 minutes ago, sandyk said:

 You always come out on the side of measurements to attempt to prove what others report hearing is not due to  their hearing above the thresholds generally quoted for older people. 

 At John's age for example, he shouldn't be able to notice tape hiss either, let alone miniscule amounts of IMD. 

Hearing Loss -Steve Hoffman Forums.jpg

 

Read it again. I didn't try to prove anything, and didn't mention measurements. How's your eyesight? I have concerns.

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12 minutes ago, pkane2001 said:

 

Read it again. I didn't try to prove anything, and didn't mention measurements. How's your eyesight? I have concerns.

Typical insults from you, with the graph I posted showing that your suggested causes of such minute levels of IMD,  should not be possible.

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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20 minutes ago, pkane2001 said:

 

So because you believe what I said might be impossible you feel the need to attack me personally?

 

John

 As the OP you have the ability to request OP privileges and remove all of this this personality clash stuff between a purely Measurements based member and myself who believes that pertinent measurements are indeed valuable, but NOT the be all, end all.

As you appear to have rethought your original post, perhaps this thread should be permitted to wind down out in the absence of further new input from you ?

Alex 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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1 hour ago, firedog said:

Because hearing also involves processing in the brain. It's not just your ears. That's why I can still (with typical age compromised ears) still tell mp3 from CD. Many younger people can't. It's not their ears, it's their brain, which hasn't been taught the difference, so they don't notice it.

You hit the nail on the head.... (pun intended.)

We can accomodate a lot of things about what we hear.   Some of us make hiss go away, some can actually ignore the FA compression, some people's hearing adjust down their bass or treble sensitivity when there is too much.

There is a 'kind of' agc going on in our hearing system.

 

Likewise, when we start missing the highest highs, or the lows disappear because we have troubles hearing those frequency regions, there is no real indication that we are missing those  Our brains adjust to the fact that we don't hear those sounds any more, and all seems normal, but not really.

 

I used to be very sensitive to frequencies well above 18kHz, and moderately strong signals above 20kHz, but now I have troubles starting in the 14kHz region.   I don't feel like I am missing anything, but I really am.

 

I can also sometimes hear the temporal distortion caused by MP3, but in my case, I can only hear it on already defective material that goes beyond normal audio signals -- and that hint tells me that other  people with more acute hearing in that area just might be able to detect mp3 in less extreme conditions.

 

 

John

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On 3/25/2021 at 4:49 AM, firedog said:

Because hearing also involves processing in the brain. It's not just your ears. That's why I can still (with typical age compromised ears) still tell mp3 from CD. Many younger people can't. It's not their ears, it's their brain, which hasn't been taught the difference, so they don't notice it.

 

I would love to have been there for the blind testing. 🙂

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How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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54 minutes ago, lucretius said:

 

I would love to have been there for the blind testing. 🙂

About the 'age compromised' ears...  Sometimes my hearing goes berserk (as you have seen me complain before), but oddly -- SOMETIMES when my hearing goes defective, I seem to be better at hearing defects that I couldn't easily hear otherwise.   I will NEVER make strong claims about always being able to hear differences between different recording formats, but IN SOME WAYS, 'age compromised' hearing might actually make it easier to detect certain impairments in a recording?!?!  (punctuation means, not sure....)

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If you believe the chart below there are practically no first order harmonics above 10k for acoustic instruments and second order harmonics take

very little hit outside of violin and cymbals for content lost above 10K.

 

http://blog.landr.com/wp-content/uploads/2016/12/Instrument_Frequency_Chart.jpg

 

As to high frequency hearing, I always do this exercise when it feels dulled. Pinch nose, blow until you feel pressure in ears, then swallow to equalize.

 

 

Regards,

Dave

 

Audio system

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6 minutes ago, davide256 said:

If you believe the chart below there are practically no first order harmonics above 10k for acoustic instruments and second order harmonics take

very little hit outside of violin and cymbals for content lost above 10K.

 

http://blog.landr.com/wp-content/uploads/2016/12/Instrument_Frequency_Chart.jpg

 

As to high frequency hearing, I always do this exercise when it feels dulled. Pinch nose, blow until you feel pressure in ears, then swallow to equalize.

 

 

 

http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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37 minutes ago, firedog said:

For the interested ones I point out the differences. Like other things in listening, once you are aware of them, you can suddenly hear them. The downside is that I've ruined mp3 listening for them.😃

I wonder if the hearing but not consciously noticing might be responsible for: tiredness, headaches, less listening to music for enjoyment rather than music as a background, etc.

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17 minutes ago, GregWormald said:

I wonder if the hearing but not consciously noticing might be responsible for: tiredness, headaches, less listening to music for enjoyment rather than music as a background, etc.

 

Anything's possible, but how do you confirm that this is the case, and not the other way around: tiredness and headaches cause sound quality to appear worse? 

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5 minutes ago, pkane2001 said:

 

Anything's possible, but how do you confirm that this is the case, and not the other way around: tiredness and headaches cause sound quality to appear worse? 

Individually: maybe the way I inadvertently tested a set of cables. I put in the new cables and loved the new clarity. A month later I noticed that I was turning the volume down or off often and not enjoying the music as much as previously. I went back to the old cables and my listening returned to *my* normal.

 

So, record listening habits, headaches, fatigue, etc. for a month or so, then swap the library for an MP3 version and record again. This could be arranged to be 'blind' for those that can't already tell the difference.

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