Hi-jacked thread split off from Single or dual differential planet10 
Hmmm. What's "natural sounding"? Is a clarinet natural sounding? If you look at its spectra, it's virtually all odd-order harmonics. And what about the piano which actually produces aharmonic components?
se
AKSA said:
Hmmm. What's "natural sounding"? Is a clarinet natural sounding? If you look at its spectra, it's virtually all odd-order harmonics. And what about the piano which actually produces aharmonic components?
se
AKSA said:
Why thank you. 🙂
So, what's "natural sounding"? You said that ideally one wants a distortion spectrum which is not too dissimilar to that found in the natural world. I'm just trying to figure out exactly what you mean by this.
se
Steve,
One where the proportions of harmonics created by the machine perform minimal spectral shift on the sounds which are being processed.
Given that distortion is largely inevitable, it would seem that outputs richer in the lower orders, with progressively lessening magnitudes as the order rises, would be most likely to preserve the natural proportions of complex tones introduced at the input. This would include your oboe, and a trumpet or horn played hard.
This approach would tend to more closely preserve the relative proportions of the harmonic structures, giving the natural timbre of the instrument. It would militate against odd order for musical reasons, and foster creation of low order harmonics over higher order. The distortion spectrum of a single ended triode would appear to fit this requirement, even though the magnitude of the distortion sums, THD, is actually very higher, since it favors H2 and H3 only.
This argument is largely based on the fact that the ear is not sensitive to large levels of H2, up to about 2%, yet hypersensitive to odd, higher orders, such as H7 (around 0.05% according to studies I have seen of the differences between soft and hard trumpet sounds.)
Cheers,
Hugh
One where the proportions of harmonics created by the machine perform minimal spectral shift on the sounds which are being processed.
Given that distortion is largely inevitable, it would seem that outputs richer in the lower orders, with progressively lessening magnitudes as the order rises, would be most likely to preserve the natural proportions of complex tones introduced at the input. This would include your oboe, and a trumpet or horn played hard.
This approach would tend to more closely preserve the relative proportions of the harmonic structures, giving the natural timbre of the instrument. It would militate against odd order for musical reasons, and foster creation of low order harmonics over higher order. The distortion spectrum of a single ended triode would appear to fit this requirement, even though the magnitude of the distortion sums, THD, is actually very higher, since it favors H2 and H3 only.
This argument is largely based on the fact that the ear is not sensitive to large levels of H2, up to about 2%, yet hypersensitive to odd, higher orders, such as H7 (around 0.05% according to studies I have seen of the differences between soft and hard trumpet sounds.)
Cheers,
Hugh
While I will not get into whether even or odd harmonics are universally preferrable (except for 2nd order, which is masked to some extent by the harmonic distortion of the speaker, as well as the harmonic distortion of the air (temperature and moisture dependant)), I would like to point out that, in theory, disregarding the odd/even issue, any harmonic distortion that is lower than the fundamental by about 40dB per octave should be inaudible. This is because of the masking threshold of the ear, which exhibits a roughly 6th order slope, according to (amongst other) the MPEG psychoacoustic model (which does remarkably well, considering what the priorities were; the modern derivate MPC is actually quite decent 😎 )...
The problem is that a complementary differential stage will tend to have harmonics that range pretty far up. And, at H7, the sensitivity of the ear should be such that the component needs to be down by about 280dB.
Obviously, in practice, it would probably suffice for it to be below the noise floor of the ear, but that depends on the net acoustic output; my guess is, if H7 is down by 120dB, relative to H1, it is inaudible in a hearing man's home. Even so, -120dB H7 is a figure that is hard to reach without introducing feedback loops, and thus time domain distortion, which the ear is even more sensible to. 
The problem is that a complementary differential stage will tend to have harmonics that range pretty far up. And, at H7, the sensitivity of the ear should be such that the component needs to be down by about 280dB.
Obviously, in practice, it would probably suffice for it to be below the noise floor of the ear, but that depends on the net acoustic output; my guess is, if H7 is down by 120dB, relative to H1, it is inaudible in a hearing man's home. Even so, -120dB H7 is a figure that is hard to reach without introducing feedback loops, and thus time domain distortion, which the ear is even more sensible to.
AKSA said:
Ok. But wouldn't that basically demand a reduction of all distortion components?
The reason I queried you is that your statement seemed to imply that in the natural world, harmonics have some particular characteristic which is somehow alien to the characteristics found in various amplifiers.
Hmmmm. Doesn't that typically describe most amplifiers? Don't often see amplifiers with a distortion characteristic where the higher order components increase with frequency.
I still don't see that there's any particular dominance of even or odd ordered distortion across musical instruments. So I don't see that odd ordered or even ordered harmonics would necessarily be any more natural or preferential.
What studies are you referring to? I haven't seen any which have shown we're more sensitive to odd ordered distortion versus even order. However there have been those which have shown that we're more sensitive to higher order harmonics versus lower order harmonics whether even or odd.
se
Steve,
I have neither the time nor the stomach to substantiate all my comments to the nth degree. It seems my entire post is contested!!
Some of your responses are pretty obviously off the mark; I was making no assumption that the harmonics found in amps are somehow alien; odd statement indeed. Your comment about rising distortion components with frequency is never observed in real life; not a single amp I've seen does this either, but they do all differ slightly.
I never stated or implied this at all. I'm talking of the amplifier, not the instrument. Please read the comment, and try to be faithful to the original statment.
I will dig up some studies on odd v. even order material, and present it here. Your not knowing of such studies is not surprising; it is psychoacoustic information not usually studied by audio designers. Don't be misled by the spectral composition of instruments; the issue is amplifiers, not the instruments.
My comments, and indeed those of most here, are made in the spirit of informal discussion, not a full-on IEEE paper. They are based on my experiences, my observations over a long period, and because they are the preserve of just one man, they are opinions, just that. Passion about a topic does not preclude the possibility of being wrong, and arrogance in any field only obscures the truth.
You tend to destroy discussion when you become combative, and challenge everything stated as an opinion. Be tolerant of that with which you disagree; there is always the possibility the other guy is right; this should never be discounted. You have caused concern here before; please don't choke debate and interesting points made by various posters here - I speak for Walt, PRR, John, as well as others, and of course, those who wish to learn more.
Cheers,
Hugh
I have neither the time nor the stomach to substantiate all my comments to the nth degree. It seems my entire post is contested!!
Some of your responses are pretty obviously off the mark; I was making no assumption that the harmonics found in amps are somehow alien; odd statement indeed. Your comment about rising distortion components with frequency is never observed in real life; not a single amp I've seen does this either, but they do all differ slightly.
I never stated or implied this at all. I'm talking of the amplifier, not the instrument. Please read the comment, and try to be faithful to the original statment.
I will dig up some studies on odd v. even order material, and present it here. Your not knowing of such studies is not surprising; it is psychoacoustic information not usually studied by audio designers. Don't be misled by the spectral composition of instruments; the issue is amplifiers, not the instruments.
My comments, and indeed those of most here, are made in the spirit of informal discussion, not a full-on IEEE paper. They are based on my experiences, my observations over a long period, and because they are the preserve of just one man, they are opinions, just that. Passion about a topic does not preclude the possibility of being wrong, and arrogance in any field only obscures the truth.
You tend to destroy discussion when you become combative, and challenge everything stated as an opinion. Be tolerant of that with which you disagree; there is always the possibility the other guy is right; this should never be discounted. You have caused concern here before; please don't choke debate and interesting points made by various posters here - I speak for Walt, PRR, John, as well as others, and of course, those who wish to learn more.
Cheers,
Hugh
AKSA said:
Then don't. I haven't any gun to your head.
Contested? I'm just trying to make some sense of what you said.
I didn't see it as odd.
You said that an amplifier's distortion charactertistic that should not be too dissimilar to that found in the natural world. To me this implies that an amplifier may have distortion characteristics which are not found in the natural world to any degree (how else then could it be dissimilar?). And it's in that context that I used the term "alien." As in a particular amplifier's distortion characteristics being dissimilar to that found in the natural world.
Yes. And this is why I'm still trying to make sense of your comment regarding natural sound as it relates to the natural world.
If the distortion characteristics of amplifiers aren't any different than those found in the natural world, then they can't very well be dissimilar to those found in the natural world. And if that's the case, I simply fail to see the point of your statement.
Yes, I know you're talking about the amplifier. What I'm trying to figure out is what amplifier has distortion characteristics which are dissimilar to those found in nature. I brought up acoustic insturments in the context of their being part of the natural world.
I don't often read studies by audio designers. But I don't recall having read any in the area of psychoacoustics or biometrics which have shown that we're more sensitive to odd order harmonics versus even order harmonics. But rather that we're more sensitive to high order harmonics versus low order harmonics.
The issue is amplifier distortion characteristics which are dissimilar to that found in the natural world. I used acoustic instruments as examples of the natural world and how distortion characteristics in the natural world are quite varied and to try and figure out what would be an example of an amplifier whose distortion characteristics are dissimilar to that found in the natural world.
Certainly. But even the comments we make informally are typically intended to make some sort of sense and as I said above, I'm just trying to make some sense of what you said regarding distortion characteristics and the natural world.
That's fine. I'm just trying to figure out what exactly you're referring to when you mention the distortion characteristics of the natural world.
Combative? Where have I been combative here? You made a statement which didn't make much sense to me and I've been trying to make some sense of it by questioning what you'd said. How is that combative? And how is it destroying discussion? This IS a discussion. By my dictionary:
a consideration of a question in open and usu. informal debate
I have been quite tolerant. If anyone is being intolerant here it is yourself, trying to characterize my questioning of your statement as "combative."
Choke debate? Who's the one choking debate? It's becoming obvious that you're the one trying to choke discussion and debate by trying to mischaracterize any sort of questioning or challenging as "combative."
So what do you really want, Hugh? Do you want discussion and debate or do you want everyone to either never question and agree with everything or just shut up?
That's rather condescending isn't it? Aren't these people capable of speaking for themselves? And when exactly did these people elect you to be their spokesman?
And finally, how else do we learn except through questioning, discussion and debate?
se
AKSA, actually you have stuck your head out a bit. I don't know of any definitive info that demands a series of harmonics in a certain way, EXCEPT that higher order odd components are very bad. This includes 7th,9th, etc.
However, I agree with your right to state your opinion and working hypothesis of what makes a good sounding amp.
In earlier years, I used to go all out and manually balance out any residual even order harmonics, in order to get the distortion as low as possible. Today, I leave a little to a lot of even order harmonics in the final output, because your hypothesis has some merit.
SE will attack each and every one of us, not matter what we put down here, sooner or later At least that is my hypothesis. 🙂
However, I agree with your right to state your opinion and working hypothesis of what makes a good sounding amp.
In earlier years, I used to go all out and manually balance out any residual even order harmonics, in order to get the distortion as low as possible. Today, I leave a little to a lot of even order harmonics in the final output, because your hypothesis has some merit.
SE will attack each and every one of us, not matter what we put down here, sooner or later At least that is my hypothesis. 🙂
Hi Steve,
You are quite right, and I apologize for including them in my post. I do not have the right to speak for them.
I'll try to find that research and get back to you later.
Cheers,
Hugh
You are quite right, and I apologize for including them in my post. I do not have the right to speak for them.
I'll try to find that research and get back to you later.
Cheers,
Hugh
john curl said:
There was no attack, John. With the possible exception of your statement above. I spent $2.95 for that New York Times article you were interested in and sent it to you and this is the thanks I get?
se
AKSA said:
Thanks, Hugh.
And I'm not claiming that we're not more sensitive to odd-order distortion versus even-order. Only that I haven't seen any research bearing that out, but have seen plenty which shows that we're less sensitive to low order versus high order due to masking.
se
Hugh, including us was OK. I think that I can also speak for Walt, as we have been friends for 30 years and I know him pretty well.
Let me help with this even-odd topic:
'Science and Music' Sir James Jeans 1937 p. 87 This book is available through Dover.
"... The seventh harmonic, however, introduces an element of discord; if the fundamental note is c', its pitch is approximately b (flat) ''', which forms a dissonace with c. The same is true of the ninth, eleventh, thirteenth, and all higher ODD-numbered harmonics; these add dissonance as well as shrillness to the fundamental tone, and so introduce a roughness or harshness into the composite sound. The resultant quality of tone is often described as METALLIC"
Well folks what do you think that this means?
This is not the first time that I have quoted this passage over the years, but it just gets ignored by those who would not learn from it. SE has told me, in print, to sell my books, since my personally having them is a waste of time and space. Here is one exception to his assertion. 😎
Let me help with this even-odd topic:
'Science and Music' Sir James Jeans 1937 p. 87 This book is available through Dover.
"... The seventh harmonic, however, introduces an element of discord; if the fundamental note is c', its pitch is approximately b (flat) ''', which forms a dissonace with c. The same is true of the ninth, eleventh, thirteenth, and all higher ODD-numbered harmonics; these add dissonance as well as shrillness to the fundamental tone, and so introduce a roughness or harshness into the composite sound. The resultant quality of tone is often described as METALLIC"
Well folks what do you think that this means?
This is not the first time that I have quoted this passage over the years, but it just gets ignored by those who would not learn from it. SE has told me, in print, to sell my books, since my personally having them is a waste of time and space. Here is one exception to his assertion. 😎
john curl said:
Why do you have to speak for Walt? He posts here. He's perfectly capable of speaking for himself.
Since you've taken it upon yourself to publically put words in to Walt's mouth, I think it only fair that I ask him publically if those words accurately reflect his sentiments.
Here are the words (regarding myself) which you are putting into Walt's mouth:
You have caused concern here before; please don't choke debate and interesting points made by various posters here -
Walt?
se
Well, it appears that SE has highjacked yet another thread.
Still, I hope that most of you can understand that higher order ODD harmonics are sonically problematic. Even harmonics, if extended beyond the 10th or so, might also be a problem as well, but they are difficult to generate in any significant amounts to be very important.
It can be debated whether 2'nd harmonic is really necessary to make good sounding audio reproduction. Analog tape, for example, has virtually no 2'nd harmonic distortion, just 3rd and sometimes 5th harmonic, yet can be very pleasant to listen to, without adding 2'nd harmonic to the mix.
Still, I hope that most of you can understand that higher order ODD harmonics are sonically problematic. Even harmonics, if extended beyond the 10th or so, might also be a problem as well, but they are difficult to generate in any significant amounts to be very important.
It can be debated whether 2'nd harmonic is really necessary to make good sounding audio reproduction. Analog tape, for example, has virtually no 2'nd harmonic distortion, just 3rd and sometimes 5th harmonic, yet can be very pleasant to listen to, without adding 2'nd harmonic to the mix.
John,
Thank you for your information on Jeans. Fascinating!
Steve,
You have indeed threadjacked here. Your behavior has been appalling.
Your actions have effectively muzzled friendly debate. A great pity.
And fer crissakes, please learn to spell.
Hugh
Thank you for your information on Jeans. Fascinating!
Steve,
You have indeed threadjacked here. Your behavior has been appalling.
Your actions have effectively muzzled friendly debate. A great pity.
And fer crissakes, please learn to spell.
Hugh
Trying to get back on track...
First, somefolks should just be ignored. Perhaps if no one rose to take the bait, the postings would subside. To this end, perhaps an ignore button would be helpfull - the selected person's posts would be invisible?
But anyway, accepting the evidence as presented, what effects would the various topology's have on the error spectrum? That really is the underlying question here - and the one this neophyte would like to understand better.
First, somefolks should just be ignored. Perhaps if no one rose to take the bait, the postings would subside. To this end, perhaps an ignore button would be helpfull - the selected person's posts would be invisible?
But anyway, accepting the evidence as presented, what effects would the various topology's have on the error spectrum? That really is the underlying question here - and the one this neophyte would like to understand better.
john curl said:
I've hijacked nothing. I simply questioned a statement made regarding harmonics and the natural world. So unless the original statement hijacked the thread, I fail to see how questioning that statement constitutes hijacking.
se
AKSA said:
Excuse me? How does questioning statements made in the course of a discussion constitute threadjacking? If that's the case, then nothing can ever be questioned and there can never be any debate. As far as I'm aware, the purpose of these forums aren't just for people to sit around agreeing with everything everyone else says.
If there was any threadjacking going on here it happened when you and John turned it into a personal issue. Prior to that, everything I had said relatedl solely to your statement regarding harmonics and the natural world.
The debate was muzzled and the thread hijacked when you and John decided to turn it into a personal issue.
I rest my case.
se
Re: Trying to get back on track...
Just click on my moniker to pull up my profile and at the bottom of the profile, click on "Add Steve Eddy to Your Ignore List."
Simple as that.
se
Sawzall said:
Just click on my moniker to pull up my profile and at the bottom of the profile, click on "Add Steve Eddy to Your Ignore List."
Simple as that.
se
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