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

[pkane2001]

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.

[pkane2001]

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?

[pkane2001]

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. 

 

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

[pkane2001]

Just now, sandyk said:

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

 

 

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

[pkane2001]

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? 

[pkane2001]

12 minutes ago, GregWormald said:

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.

 

That's been done with equipment. A test where a randomly selected component (of two) was put into the circuit each time the system was turned on. The listener didn't know which one it was. The test circuit also tracked how much time the listener spent with each component over a period of a few months. The expectation was that a better sounding component would make it easier to listen to, and the listener would spend more time with it. In the end, the result wasn't very conclusive. I posted on this test before, but will need to locate the description for more of the details. It wasn't a true experiment, just a simple test by a single individual, but does point to a possible way to test these types of explanations.