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Discussion Starter #1 (Edited)
Well, I can't really hear those high frequencies--but I can perceive them. Everyone can! People argue about CD this vs. LP that all the time when they should really be arguing about the best way to capture and reproduce harmonics. Why? Because harmonics are one of the details where music lives, and we all know the :devil: is in the details! And what are harmonics? Well, they are how we can tell instruments apart.

At this point you may be thinking it makes no difference to CD's because you can still tell an oboe apart from a clarinet or a guitar apart from a fiddle. And you'd be right; except that when you change the conversation to ultimate sound quality, you now want to be able to tell one violin apart from another. So let the discussion begin! Do you think this can of worms holds any water? Why or why not? As source for thought I cite two references:

Reference #1 (paraphrased excerpt):
"A pure note consisting entirely of one frequency will sound boring. The harmonics are missing. Harmonics are integer multiples of the fundamental frequency. The first harmonic is the fundamental frequency, 264Hz for middle C. The second harmonic will be twice this frequency, 528 Hz, which is an octave higher. The third harmonic will be three times the fundamental frequency, 792Hz, and so on. The violin, piano, and guitar all produce sounds by vibrating strings. Playing the same note, say middle C, will produce a tone with a fundamental frequency of 264 cycles per second. Yet all three instruments sound different because they have different harmonics. The amount of each harmonic present is what gives each musical instrument its own unique sound. A well made instrument will sound richer than a poorly made one because it will have better harmonics. An instrument with no harmonics will sound like a tuning fork with only one fundamental frequency present."

Reference #2 (paraphrased excerpt:)
Section X. Significance of the results
"Given the existence of musical-instrument energy above 20 kilohertz, it is natural to ask whether the energy matters to human perception or music recording. The common view is that energy above 20 kHz does not matter, but AES preprint 3207 by Oohashi et al. claims that reproduced sound above 26 kHz "induces activation of alpha-EEG rhythms that persist in the absence of high frequency stimulation, and can affect perception of sound quality."
Oohashi and his colleagues recorded gamelan to a bandwidth of 60 kHz, and played back the recording to listeners through a speaker system with an extra tweeter for the range above 26 kHz. This tweeter was driven by its own amplifier, and the 26 kHz electronic crossover before the amplifier used steep filters. The experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter, and also denied, when presented with the ultrasonics alone, that any sound at all was being played. "
 

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Discussion Starter #2
:scratchhead: People are staying away. Did I say something wrong? I didn't mean this as a flame or to troll. I'm genuinely interested in your thoughts. Should I have used the word "discussion" instead of "argument"? Do most/all of you rank this topic up there with snake oil?

Please reply or PM me, as I welcome constructive criticism!
TIA
 

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Personally I don't care about the science behind such things. I let my ears tell me what I hear and decide from there. The whole LP vs CD is old and the reality is that most people don't care unless they have invested a huge amount in an LP setup the winner is easy. Plus it was already mentioned in the other thread that channel separation on vinyl as well as bass is mono so you must have a high end table and cartridge to gain from it.
 

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Discussion Starter #5
Thanks for checking in... I do appreciate the feedback. I'll get the hang of this thread-starting thing one of these days, you'll see. :R

Just to sum up and not leave this thread up in the air... Harmonics grow steadily weaker has they go higher in scale. I think anyone would be hard pressed to hear a difference even if fragile harmonics could be preserved through the whole recording/listening chain. Hey, maybe that could be a selling point for snake-oil cables: "We preserve upper harmonics, so you don't have to!"

Our listening media, systems and rooms--with all their faults--still allow us to tell the difference between similar instruments. Most of the harmonics that make a difference are within our range of hearing, so super-tweeters need not apply. Chalk this can of worms up to Great Audio Myth #_____.
 

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Hey, Lou, just catching up. I find this very interesting, not just in how it relates to CD vs vinyl, but in how it could possibly explain other preferences. Amp A vs Amp B, for instance. I have wondered if there might be some "other sense" involved sometimes where an amp or DAC or medium is clearly preferred by certain listeners, or where it is only after extended listening that a difference becomes apparent. The alpha-EEG reference is the first work that I have heard of that looks at possibilities of perception beyond but related to hearing. To someone who has "tuned into" that other dimension of perception, they might very well associate it with their hearing, as it would seem natural to do.

Having dealt with meditation and hypnosis - OK, we are way out of the audio field now - I can testify that an increase in alpha waves when self-induced definitely feels different, more peaceful, very pleasant. If a listener experienced this while listening to vinyl, or a different amplifier, or a different speaker cable - I know it is a stretch, but we are just brainstorming here - that "pleasant, peaceful" feeling could be perceived as part of the listening experience and lead to an equipment or technology preference. And would be very real and potentially repeatable, for the attuned listener, under the right set of test circumstances.

Edit: Some listeners might have have a tendency to "tune out" that other area of perception altogether, or when doing critical listening. And it might not be conducive to A/B testing. But if a listener is "tuned into" that perception and associates it with the listening experience, then it is as valid to that listener as soundstage or distortion or any other aspect of the listening experience. And someday might even be a measurable system parameter.
 

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Couldn't the extended frequency response also effect the tonality of the instruments or vocals?
 

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Just speculating, if the extended response is directly associated with hearing, then it would seem like it could affect the perception of tonalities. If it is more of a "nice feeling," then it seems like it would not.
The reason I said this is every note has overtones (?), and if you chop off a part of it... What happens to the original note. I am thinking it is possible that chopping off the overtone could effect the original tone...maybe tonally. Not sure how you would be able to prove it one way or another though.
 

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The only way I can think of to test the theory would be...

Take a tone and digitally chop it off directly at the frequency, and take another tone and leave it alone, and then listen to the 2 tones, and see if there is any audible difference. Feasible?
 

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We do that all the time already with filtering. If the overtones that are chopped off were audible in the first place, then tonality is definitely changed. If those overtones that are chopped off by filtering were not audible, then there is no apparent change to the sound, and no change in totality. Overtones are all in our heads, in that it is our brains that associate those frequencies as all part of 1 sound.

Edit: For instance, an additive synthesizer creates its sound by adding components that when combined make up the overtones of the overall sound. The old Hammond organ is the same way, where frequencies are added together to create what we interpret as a sound of a single note, but in reality they are just frequencies with certain relationships. The timing envelope of the sound gives us cues that those different components are all part of the same sound. All those overtones are just separate frequencies until our brain tells us they are part of a single sound.
 

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We do that all the time already with filtering. If the overtones that are chopped off were audible in the first place, then tonality is definitely changed. If those overtones that are chopped off by filtering were not audible, then there is no apparent change to the sound, and no change in totality. Overtones are all in our heads, in that it is our brains that associate those frequencies as all part of 1 sound.

Edit: For instance, an additive synthesizer creates its sound by adding components that when combined make up the overtones of the overall sound. The old Hammond organ is the same way, where frequencies are added together to create what we interpret as a sound of a single note, but in reality they are just frequencies with certain relationships. The timing envelope of the sound gives us cues that those different components are all part of the same sound. All those overtones are just separate frequencies until our brain tells us they are part of a single sound.
Thanks for clearing that up for me... It's all just in my head then. :T
 

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Discussion Starter #13
Hey, Lou, just catching up. I find this very interesting, not just in how it relates to CD vs vinyl, but in how it could possibly explain other preferences. Amp A vs Amp B, for instance. I have wondered if there might be some "other sense" involved sometimes where an amp or DAC or medium is clearly preferred by certain listeners, or where it is only after extended listening that a difference becomes apparent. The alpha-EEG reference is the first work that I have heard of that looks at possibilities of perception beyond but related to hearing. To someone who has "tuned into" that other dimension of perception, they might very well associate it with their hearing, as it would seem natural to do.
Are any marketing people out there listening to this? It's golden! Ad copy: "Our amp doesn't just take you there, it transports you into the next dimension" Sorry Wayne, I couldn't resist. I do think slight differences in harmonic content may affect how listener's perceive Amp A vs. B, especially if one of them produces odd-order vs even-order distortion artifacts. What might otherwise look like an even playing field on paper might in actuality be a stacked deck. If we take brainstorming into the realm of distortion, even-order harmonics are supposedly more pleasing to the ear. Tube advocates' claim that odd-order harmonic distortion is largely to blame for solid state gear's unpleasant "sound." The solid state camp says that tubed gear's introduction of large amounts of distortion (even-order or not), disqualifies it from serious consideration.

Having dealt with meditation and hypnosis - OK, we are way out of the audio field now - I can testify that an increase in alpha waves when self-induced definitely feels different, more peaceful, very pleasant. If a listener experienced this while listening to vinyl, or a different amplifier, or a different speaker cable - I know it is a stretch, but we are just brainstorming here - that "pleasant, peaceful" feeling could be perceived as part of the listening experience and lead to an equipment or technology preference. And would be very real and potentially repeatable, for the attuned listener, under the right set of test circumstances.
Yup, "'pleasant, peaceful' feeling". Wasn't that an Eagles song? :R
I imagine self-induced alpha waves could influence preferences for equipment, media, and even artistic genre. That's an interesting premise that spills over into any habitual, self-gratifying activity like smoking for instance. I think for the purposes of listening we mean to entertain more subliminal notions such as pleasant aroma while auditioning Amp A as opposed to intrusive outdoor noise while listening to Amp B.

Edit: Some listeners might have have a tendency to "tune out" that other area of perception altogether, or when doing critical listening. And it might not be conducive to A/B testing. But if a listener is "tuned into" that perception and associates it with the listening experience, then it is as valid to that listener as soundstage or distortion or any other aspect of the listening experience. And someday might even be a measurable system parameter.
Oh, the possibilities... one could only hope for tighter correlation between what we hear or think we hear, and what can be mesured.
 

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Discussion Starter #14
The reason I said this is every note has overtones (?), and if you chop off a part of it... What happens to the original note. I am thinking it is possible that chopping off the overtone could effect the original tone...maybe tonally. Not sure how you would be able to prove it one way or another though.
The only way I can think of to test the theory would be...
Take a tone and digitally chop it off directly at the frequency, and take another tone and leave it alone, and then listen to the 2 tones, and see if there is any audible difference. Feasible?
I think that "chop" is the operative term here. If we're talking digital brick-wall filtering, that introduces artifacts in and of itself (e.g. ringing, group delay, etc.). May or may not be a fair comparison depending on who you ask. I'm willing to accept the chopped signal as being clean enough for our thought experiment.


We do that all the time already with filtering. If the overtones that are chopped off were audible in the first place, then tonality is definitely changed. If those overtones that are chopped off by filtering were not audible, then there is no apparent change to the sound, and no change in totality. Overtones are all in our heads, in that it is our brains that associate those frequencies as all part of 1 sound.

Edit: For instance, an additive synthesizer creates its sound by adding components that when combined make up the overtones of the overall sound. The old Hammond organ is the same way, where frequencies are added together to create what we interpret as a sound of a single note, but in reality they are just frequencies with certain relationships. The timing envelope of the sound gives us cues that those different components are all part of the same sound. All those overtones are just separate frequencies until our brain tells us they are part of a single sound.
I'm no acoustician or physicist, but I would agree our ear-brain mechanisms interpret a note from say, a flute as a single sound. In the case of multiple sounds presented together, I believe throwing away lower magnitude signals in favor of larger ones changes the sound. MP3 technology bases its psycho-acoustic modelling on this type of masking.
 

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Discussion Starter #15
Couldn't the extended frequency response also effect the tonality of the instruments or vocals?
You said it better than I could. I was trying to convey the difference between
  1. the same instrument with and without overtones, and
  2. similar instruments (e.g. clarinet & flute) with and without overtones
 

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It is quite amazing all the things the psycho-acoustical brain does for us on a moment-by-moment basis. Pluck a stretched-out string, and the brain can estimate length, tension, material, where along its length it was plucked, what kind of material was used to pluck it with, all from the volume envelope and harmonic structure, which the brain recognizes as basic in nature. Blow on a pipe, and a certain set of harmonics is produced, and the brain can tell material, length, whether it was a flute or a clarinet or a pipe organ from envelope and odd and even harmonic ratios. It can even fill in the missing fundamental for us if the speaker's frequency response is not quite low enough. It can do a pretty good job of recognizing an instrument even if its harmonic structure has been drastically filtered. And it can recognize an instrument that is being simulated, if the simulation is close enough, as produced by a synthesizer. And of course it can sometimes recognize, with experience, subtle differences due to amplifier or speaker design variations. Change the harmonic structure enough, and it sounds like a different instrument or even a new instrument.

The brain's recognition of harmonic structure is very basic to our navigating the world of sound on a moment-by-moment basis, and is certainly very fundamental to our analysis, interpretation, and appreciation of music and audio.
 

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The reason I said this is every note has overtones (?), and if you chop off a part of it... What happens to the original note. I am thinking it is possible that chopping off the overtone could effect the original tone...maybe tonally. Not sure how you would be able to prove it one way or another though.
The only way I can think of to test the theory would be...

Take a tone and digitally chop it off directly at the frequency, and take another tone and leave it alone, and then listen to the 2 tones, and see if there is any audible difference. Feasible?
Please forgive the brevity of my earlier response, it was not very clear.

Yes, what you are saying is correct. If some of the harmonics of a note are removed or reduced, or increased for that matter, it affects the sound of that note, absolutely. The psycho-acoustical brain recognizes it as a change to the original note or tone, recognizes it as the same note but modified.

This is an everyday occurrence in the modern recording studio, when a producer asks, "Can we liven up that guitar a little bit?" and the engineer responds by adding a small peak in the frequency response for that track which increases the amplitude of certain harmonics of that sound and perhaps reduces others, and it is still easily recognized by the brain as the same guitar, but it sounds slightly different. The two sounds if compared side by side, or two individual notes, as you suggest, would be easily told apart.

Our ears and brains are very sensitive to these changes. We hear them all the time and think nothing of them, but if we choose to zoom in on them, or to compare two versions of a note side by side, we can tell extremely subtle differences between them. As the OP suggests, this is a possible explanation for some of the differences that might be discernible between amplifiers or audio components of different kinds. Those subtle differences can result from many different types of design choices within a circuit (although we often forget the almighty and ever present phenomenon of negative feedback, which is present in almost every audio circuit to some degree and in some form, and its way of reducing those differences to infinitesimally small levels). And we do not really know what the limits of our perception of those tiny variations might be.
 

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Its all mastering dependent. I have heard both formats sound excellent and dreadfull with no clear winner at all.
 

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Discussion Starter #20
Our ears and brains are very sensitive to these changes. We hear them all the time and think nothing of them, but if we choose to zoom in on them, or to compare two versions of a note side by side, we can tell extremely subtle differences between them. As the OP suggests, this is a possible explanation for some of the differences that might be discernible between amplifiers or audio components of different kinds. Those subtle differences can result from many different types of design choices within a circuit (although we often forget the almighty and ever present phenomenon of negative feedback, which is present in almost every audio circuit to some degree and in some form, and its way of reducing those differences to infinitesimally small levels). And we do not really know what the limits of our perception of those tiny variations might be.
A follow-up to Audio Engineering Society paper No.3207 previously cited correctly asserts that at least one member of each instrument family (strings, woodwinds, brass and percussion) produces energy to 40 kHz or above. It basically discusses the significance of others' work on perception of air- and bone-conducted ultrasound; and points out that even if ultrasound be taken as having no effect on perception of live sound, its presence may still pose a problem to the audio equipment designer and recording engineer.

I find it extremely interesting that measurable EEG activity occurred in the presence of ultrasound, regardless of whether or not any change was detected or admitted by tested participants (ref excerpt below). Only a few instruments generate ultrasonic harmonics, and may not be played in the majority of music favored by an individual, but at least one--the crash cymbal--generates significant energy up to 100kHz. How many audio systems realistically reproduce cymbals? How many also annoyingly distort sibilants?

In any case, I'm still not arguing for or against either analog or digital formats. In my experience, analog is more relaxing. Like your premise these studies infer why.

Excerpt:
X. Significance of the results
Given the existence of musical-instrument energy above 20 kilohertz, it is natural to ask whether the energy matters to human perception or music recording. The common view is that energy above 20 kHz does not matter, but AES preprint 3207 by Oohashi et al. claims that reproduced sound above 26 kHz "induces activation of alpha-EEG (electroencephalogram) rhythms that persist in the absence of high frequency stimulation, and can affect perception of sound quality." [4]
Oohashi and his colleagues recorded gamelan to a bandwidth of 60 kHz, and played back the recording to listeners through a speaker system with an extra tweeter for the range above 26 kHz. This tweeter was driven by its own amplifier, and the 26 kHz electronic crossover before the amplifier used steep filters. The experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter, and also denied, when presented with the ultrasonics alone, that any sound at all was being played.

Even if we assume that air-conducted ultrasound does not affect direct perception of live sound, it might still affect us indirectly through interfering with the recording process. Every recording engineer knows that speech sibilants ....<snip>.... and muted trumpets can expose problems in recording equipment. If the problems come from energy below 20 kHz, then the recording engineer simply needs better equipment. But if the problems prove to come from the energy beyond 20 kHz, then what's needed is either filtering, which is difficult to carry out without sonically harmful side effects; or wider bandwidth in the entire recording chain, including the storage medium; or a combination of the two.
On the other hand, if the assumption of the previous paragraph be wrong — if it is determined that sound components beyond 20 kHz do matter to human musical perception and pleasure — then for highest fidelity, the option of filtering would have to be rejected, and recording chains and storage media of wider bandwidth would be needed.
 
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