Simple. It is irrelevant what the ear does as long as what it gets from the amp/speaker is the same as what it would get from a live sound. In that case it will hear the sound exactly as it originally is. Even if the ear would transpose all frequencies, it still would say: that sounds the same / great!
With threshold I mean its ability to discern differences. If a difference of 5 degrees in phase is unnoticeable, then your transparent amp can have up to 5 degrees of phaseshift and still sound (to the ear) as the original sound.
That was one of the issues with the (in)famous Cheever study. He was proposing (IIRC) an amp that follows the ear's response so as to make it sound more natural (something like that). A fundamental error in thinking.
jan didden
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Yes, possibly. These speakers look very impressive, very well done, that becomes a perception factor.
I think I answered this in the above post.
jan didden
It is generally agreed that this is impossible given current technology!
But that isn't the case - see above
We know the ear distorts incoming sound about 25%, (I have not asked about phase shift)! So why are you bothered with getting amp distortion < 20%, 10%, 1%, 0.1%?
Don't know the study but it seems like a jump of logic to say that one approach was wrong therefore all statements that you loosely say fall into this definition are wrong! The details are important
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Thanks Jacco, for providing a link to this important paper. Please understand everyone, that this sort of research has been going on for decades, and it is usually ignored by everybody, but the hi end designers and listeners.
For example, it could be equally argued, (and it has), that double blind tests 'prove' that severe bandwidth limiting at about 20KHz does nothing that anyone can hear with real music. The same goes for different amps, cables, etc.
The only area allowed, seemingly, to be 'creative' is in speaker design, where it is almost impossible to get truly accurate waveforms to the ear by any means.
One of our first 'hopes' at least mine, over 35 years ago, was the Manger approach. He REALLY did his 'homework' and developed a more 'accurate' loudspeaker, yet for me, the overall results have been disappointing.
Horns, the same thing. In many ways, they are superior to direct radiators, yet they always seem to also have so many problems of their own, that they fall short.
I don't know IF we can ever get an accurate signal through a multi way direct radiator, yet that seems to work fairly well in many cases. Why?
That said, the argument FOR extended bandwidth is well stated in the last group of linked papers, corresponding more closely to the 'old' opinions of hi fi reproduction, rather than the 'new' opinions developed in the digital age.
I am glad to see serious researchers actually using their ears to attempt to improve audio quality, and attempting to mathematically model their work, rather than obscure it in 'double blind testing', and attempting to 'prove' that 'everything sounds the same'.
For example, it could be equally argued, (and it has), that double blind tests 'prove' that severe bandwidth limiting at about 20KHz does nothing that anyone can hear with real music. The same goes for different amps, cables, etc.
The only area allowed, seemingly, to be 'creative' is in speaker design, where it is almost impossible to get truly accurate waveforms to the ear by any means.
One of our first 'hopes' at least mine, over 35 years ago, was the Manger approach. He REALLY did his 'homework' and developed a more 'accurate' loudspeaker, yet for me, the overall results have been disappointing.
Horns, the same thing. In many ways, they are superior to direct radiators, yet they always seem to also have so many problems of their own, that they fall short.
I don't know IF we can ever get an accurate signal through a multi way direct radiator, yet that seems to work fairly well in many cases. Why?
That said, the argument FOR extended bandwidth is well stated in the last group of linked papers, corresponding more closely to the 'old' opinions of hi fi reproduction, rather than the 'new' opinions developed in the digital age.
I am glad to see serious researchers actually using their ears to attempt to improve audio quality, and attempting to mathematically model their work, rather than obscure it in 'double blind testing', and attempting to 'prove' that 'everything sounds the same'.
This whole thing about the ear distorting 25 or 30 % to me is complete and utter nonsense, and let's not make this fallacy fashionable.
Where do you plug in your frequency analyzer? Or are we talking about a different kind of distortion? If so, what? The ear is not a linear device, in the sense that it is more sensitive to some frequencies than others, but that has nothing to do with distortion.
The ear and connected auditory system are the final benchmark.
Where do you plug in your frequency analyzer? Or are we talking about a different kind of distortion? If so, what? The ear is not a linear device, in the sense that it is more sensitive to some frequencies than others, but that has nothing to do with distortion.
The ear and connected auditory system are the final benchmark.
Really? Anything to back up your "belief"?
a microphone in the ear is often used!
Why not look it up?
Correct!
"A microphone in the ear is often used." For what, to measure the distortion of the ear? How would that work?
The only "distortion" I am aware of is the occurance of difference tones at f2-f1 (f2>f1) and the cubic distortion tone 2f1-f2 (f2>f1). So, there are frequency dependant distortion products, which are audible and can even be measured on the auditory nerve, but attaching a percentage to them is something I have never found in literature.
Perhaps you can enlighten us. Where did you look it up?
vac
Just picking up these points in isolation (notably that our hearing mechanism is more complex than a simple SPL magnitude vs frequency analyser), in below post I described a simple way to self-test for this kind of psycho-acoustic phenomena, with low/mid-frequency steady-state signals that are pretty music-like...
http://www.diyaudio.com/forums/multi-way/119677-enabl-technical-discussion-108.html#post2651152
Personally I found it an eye-opener (ear-opener, that is).... for speaker design at least. Amps come way further down the list and there the amp<-->driver interface in terms of impedance vs freq is the most important point to me...
We do?? (distort 25%)
The paper you referenced via a commercial website says " As the human eardrum is highly non-linear (it distorts approximately 25 %)"
Without conditions that is pretty meaningless! Levels? Range? What type of distortion?
It is an OPINION, but you seem to have latched on to it as a revelatory axiom.
Little useful is being said here. OF COURSE, the ear creates self distortion, but the ear-brain system compensates for it, and we can hear fairly low levels of harmonic distortion, especially higher order odd harmonics (or IM products) that are unmusical in character. The absolute linearity of each part of the listening mechanism is relatively unimportant, except it MIGHT add capabilities to the human hearing mechanism such as mono phase detection under certain conditions. Therefore, this non-linear mechanism in the ear is probably very important in more subtle ways. Detection of 'absolute polarity' might be another attribute to the non-linearity of the hearing mechanism.
Hi,
There is no fallacy. It is science fact for over halve a century.
Based on the results of Georg von Békésy, Experiments in Hearing. McGraw Hill. p.335, 1960
And it has 30% 2nd Had for 94dB of 200Hz tones.
There is actually a lot more in this research.
Ciao T
There is no fallacy. It is science fact for over halve a century.
An externally hosted image should be here but it was not working when we last tested it.
Based on the results of Georg von Békésy, Experiments in Hearing. McGraw Hill. p.335, 1960
And it has 30% 2nd Had for 94dB of 200Hz tones.
There is actually a lot more in this research.
Ciao T
If you can unequivocally pontificate on the difference between the distortion in our hearing mechanism and that from mechanical transducers before the fact etc. please I'm all ears.
Maybe the ear mechanism does distort 25%. But, let's not forget the output signal then feeds the brain, which processes this signal. As in sight, some heavy processing takes place in the brain. So I do not think a statement to the effect that the ear distorts 25%, so why bother with low distortion amp designs is correct or based on sound reasoning. Secondly, if the ear distorts 25%, then how can the situation be helped by an amplifier in the signal chain that adds unnatural distortion (man made)?
And then, what are we to make of the numerous studies that claim to demonstrate the ability of humans to detect 0.2% 2nd harmonic, and even lower levels of the higher order ones. Think you need to look at hearing as a transducer+processor (brain) system. You cannot pull part of the system out and use that with it's obvious failings to set amplifier distortion specs.
Bottom line: after paying attention to to the engineering rules and caveats, lower distortion is better.
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John,
Au contraire, mon ami.
It is EXTREMELY useful and EXTREMELY important.
The ear brain system in fact does emphatically NOT compensate ANYTHING, in fact it uses this distortion as a fundamental mechanism in the way ot works.
Actually, a better way to say this would be:
"we can hear fairly low levels of harmonic distortion, especially higher order odd harmonics (or IM products) that are incongruent with ears own distortion patterns"
The counter argument incidentally is that we cannot hear gross levels of HD if it is very low order at high SPL's...
So if we talk about "distortion" we need to consider many factors.
And for IMD/THD we need to consider how the ear itself reacts.
And the fun part is that we can predict a lot of things easily once we understand how the ear works...
For example, we can understand why the gross levels in Speaker drivers do not cause complete un-listenability...
No, the LACK OF LINEARITY of the listening mechanism is ABSOLUTELY CRUCIAL in understanding how audio operates.
And not just for absolute polarity or mono detection.
Ciao T
Au contraire, mon ami.
It is EXTREMELY useful and EXTREMELY important.
The ear brain system in fact does emphatically NOT compensate ANYTHING, in fact it uses this distortion as a fundamental mechanism in the way ot works.
Actually, a better way to say this would be:
"we can hear fairly low levels of harmonic distortion, especially higher order odd harmonics (or IM products) that are incongruent with ears own distortion patterns"
The counter argument incidentally is that we cannot hear gross levels of HD if it is very low order at high SPL's...
So if we talk about "distortion" we need to consider many factors.
And for IMD/THD we need to consider how the ear itself reacts.
And the fun part is that we can predict a lot of things easily once we understand how the ear works...
For example, we can understand why the gross levels in Speaker drivers do not cause complete un-listenability...
No, the LACK OF LINEARITY of the listening mechanism is ABSOLUTELY CRUCIAL in understanding how audio operates.
And not just for absolute polarity or mono detection.
Ciao T
Can't say it better than Thorsten has done already elsewhere http://www.diyaudio.com/forums/anal...ch-preamplifier-part-ii-1325.html#post2626927
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Well T, I must agree with you in many ways, but it is possible for us to hear smallish amounts of harmonic distortion, for example, that you would think would be masked by your model. For example, 2nd harmonic should drop LINEARLY with level, so we would expect 3% second at 74 dB, but we know that we can hear better than that. Maybe 10 times or more, better. Third and higher harmonics would drop MUCH faster, so they might fit the model more exactly.
Hi,
Depends on SPL and frequency.
Yes. It would help if one actually understood the nature of this processing.
Well, I would formulate the thesis differently:
"Given the way the human hearing systems works (including the high levels of certain types of distortion present in it) low distortion must be made low in reference to the way the human hearing percieves it."
It cannot and does not.
The intuitive leap of "It has high HD levels but it sounds good so it must sound good because it adds HD" is patently untrue and it should be obvious that it is merely our prejudice that "high THD is bad" clutching at straws...
Which is why, as I pointed out above, frequency and SPL must be taken into account. Single number THD has been discredited as a measure of quality and distortion audibility for well over six decades.
Actually YOU MUST understand the systems you are talking about, otherwise it may a wiser path to not talk about them...
Bottom line, the above is an utter fallacy. It should be self-evident, incidentally.
Ciao T
Depends on SPL and frequency.
Yes. It would help if one actually understood the nature of this processing.
Well, I would formulate the thesis differently:
"Given the way the human hearing systems works (including the high levels of certain types of distortion present in it) low distortion must be made low in reference to the way the human hearing percieves it."
It cannot and does not.
The intuitive leap of "It has high HD levels but it sounds good so it must sound good because it adds HD" is patently untrue and it should be obvious that it is merely our prejudice that "high THD is bad" clutching at straws...
Which is why, as I pointed out above, frequency and SPL must be taken into account. Single number THD has been discredited as a measure of quality and distortion audibility for well over six decades.
Actually YOU MUST understand the systems you are talking about, otherwise it may a wiser path to not talk about them...
Bottom line, the above is an utter fallacy. It should be self-evident, incidentally.
Ciao T
Nobody said this - read it again! I formatted it as a question to elicit some thinking about the situation of what's going on & not a simplistic statement as you have reduced it to! Obviously my attempt has failed in your case!
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