Excellent. Thank you.
I wouldn't consider a thesis for a master's degree to be a scientific reference, as it is not peer reviewed or experimental, but it is interesting nonetheless. His listening panel of N = 5 listeners is a bit of a joke. This is what happens when engineers try to conduct scientific experiments.
I'm left with one burning question: The analysis presented in this thesis shows that low-order harmonic distortion is masked to a greater extent by our ear/brain perceptive system than high-order distortion. If this is true, why would people then prefer amplifiers that have higher low-order harmonic distortion over those that have very low distortion overall? If I understand you correctly, that's your claim, right?
As far as I read the analysis, circuits with higher low-order distortion would have a higher chance of "flying under the radar" versus those that have higher high-order distortion as the low-order distortion would be masked (i.e., not audible) to a greater extent than the high-order distortion even if the overall THD is the same. But the distortion of a circuit with ultra-low THD would then be just as inaudible as one that had relatively high low-order distortion, right? So there's no support for your claim that people on average prefer circuits that have high low-order distortion over those that have extremely low distortion. All I see is that people still prefer low distortion overall as indicated by Geddes, Belcher, et al.
The masking could help explain why THD isn't a perfect correlate of the listing experience, i.e., why the effect size is moderate rather than large as per Cohen (1988).
Tom
Not exactly. My claim only has to do with variability of what a particular THD number may represent in terms of the degree of distastefulness of reproduced sound, and or in the degree of preference for a particular sound. Its can kind of be all over the place, which is why I suspect guys like Olive and Geddes would rather see us switch to something else. If we need to have a single number metric to make it easy for consumers, there are probably better choices than THD.
This has been my observation as well.
The speaker drivers I now use have special motors and soft-parts that have a dominant 2nd harmonic over most of their usable bandwidth. (Scan-Speak) Adding even more 2nd harmonic unfortunately blurs the sound for me. On the other hand, if one has drivers with a simple motor structure, or horns with throat distortion, they typically have a dominant third and fifth harmonic, and the added 2nd harmonic distortion might be more welcome. We are looking at the harmonics of the whole acoustic system after all.
In addition, some recording eras and genre traditions add "warmth", or "dryness", or "cohesion", or "dynamic eq" , etc to mixes, and these may respond well to added odd or even distortions as harmonic compensation in the reproductive equipment. So our equipment preference may also depend on how our favorite recordings were processed...For more, Floyd Toole covers this "circle of confusion" in his book.
If one has age-related hearing loss, which usually has a corner frequency around the consonants, say 2-4 KHz, then an amplifier with elevated and rising distortion from those same frequencies may help bring more enjoyment to that listener...most tube amps for example...most SS low feedback designs for example...
For example, if we listen to a Perry Mason TV episode circa 1960 on Tom's Modulus 686, the Foley is humorously too noticeable and slightly distracting. But if we listen to that show on our PP KT88 Electrobeam II amplifier, it sounds correct relative to the dialog...now is that difference because the show was recorded on 1960's equipment whose distortion masked the Foley in the mix, and thus it was recorded at a higher level than we need with today's equipment? Dunno.
"Clarity" is a term I use for myself. e.g. do I clearly hear the familiar inner instrument voices in the orchestra that I pretend to remember hearing while sitting in the viola section all those years ago, without added aural distractions?
Am I experiencing the heartfelt musical expression and skill of the artist?
Psycho-acoustic data is very complex, varying, and difficult to quantify, BUT, after years of distortion profile tests (prejudiced tests, blind tests, accidental tests, wine-soaked tests, short tests, long tests, etc. ) my contemporary conclusion is: I prefer the lowest distortion, lowest noise equipment I can afford. This has given me the most enjoyment of music through the recordings and equipment I use. Thanks Tom!
I did chase capacitor DA around the last time it became a popular issue, and fortunately I was unable to hear or measure any effect it made to the sound.
Also, as I remember, some instruments (the trumpet?) have their 2nd harmonic as the dominant tone in their spectrum.
David
Yeah. And I keep saying that I only bring up the THD issue when someone says, as I believe someone did in earlier this thread, something more or less to the effect that if THD and noise are good enough then that's all you need know, or that it means a device audibly transparent, etc. My only point in that case is that THD or THD+N by itself is not sufficient to make claims of that nature.
Maybe I'm the only one with this interpretation but your repeated posting of the Sean Olive meme comes across as a crusade against THD measurements. This thread is one example: https://www.diyaudio.com/community/threads/help-me-start-my-measuring-tools.404864/ You posted the meme at least twice in that thread simply because someone dared to ask about how to measure distortion. Same in this thread.
THD is one of many ways to characterize an audio circuit and many of us find it relevant to measure it. Please accept this.
Tom
THD is one of many ways to characterize an audio circuit and many of us find it relevant to measure it. Please accept this.
Tom
I looked on it as an opportunity to start a conversation with the member as to why they wanted to measure THD in particular. By itself it has limited value. So why choose to measure it and noise?
The stated goal of the member looked to me like someone who might not know any better than to overly focus on THD and noise floor. Maybe too much time at that other SINAD website. Quoting Sean Olive wasn't meant as an attack, but it was intended to get the persons attention. Why would Sean Olive say what he did and why it is important? I think you may know, but a lot these guy don't.
Tom,
An argument is a connected series of statements in support of some proposition. It doesn't change being crusaded or otherwise. The suggested crusade isn't changing your view is it. Why do you care, or do you care about how many amplifiers you can't sell if someone else thinks differently from your advertising copy?
The objection to repetition suggests everyone read the post the first time. Just because you read it, as seemingly the only important person that counts, doesn't matter to you that anyone else hasn't. Think of it that the posts presented I haven't read yet and want to.
An argument is a connected series of statements in support of some proposition. It doesn't change being crusaded or otherwise. The suggested crusade isn't changing your view is it. Why do you care, or do you care about how many amplifiers you can't sell if someone else thinks differently from your advertising copy?
The objection to repetition suggests everyone read the post the first time. Just because you read it, as seemingly the only important person that counts, doesn't matter to you that anyone else hasn't. Think of it that the posts presented I haven't read yet and want to.
Last edited:
Yes. It has limited value to you. But it has great value to those of us who want to see how close our circuits are to the ideal Vout = A*Vin. Besides, the OP in that thread clearly stated they wanted to measure distortion and asked for advice on how to do that. They didn't want to measure the sound quality. In fact, they said directly that they wanted to measure opamps, which can be used in many applications and not just audio.
If I was designing a horizontal sweep circuit for an oscilloscope I would care greatly about the distortion of that circuit. I would care zero about what it sounded like. The same goes for capacitors (there! my feeble attempt to nudge this thread back on track).
Tom
And the result is.............. Peanut brain?? 🤣 🤣 🤣
Sorry.... Couldn´t help myself.......... Had to 😊
That's an interesting read! There are some other works on weighing the harmonics before summation into some figure of merit, but this one seems to derive the weights directly from measured self distortion of the ear.
That Cheever's master's thesis has been discussed here already two decades ago.
https://www.diyaudio.com/community/threads/total-aural-dissonance-the-proper-metric.39942/
Post #3 on that thread is a good summary.
https://www.diyaudio.com/community/threads/total-aural-dissonance-the-proper-metric.39942/
Post #3 on that thread is a good summary.
Ignoring the summary (post #3) by someone adding commentary sadly lacking of any hint of argument that isn't fallacious there are numerous posts later on in thread that at least suggests substance, and by the writer as well (post #17) . So thanks.
https://www.diyaudio.com/community/threads/total-aural-dissonance-the-proper-metric.39942/
https://www.diyaudio.com/community/threads/total-aural-dissonance-the-proper-metric.39942/
You seem excited. Once it cools off you might use the search functionality for "Cheever" here. There are hundreds of posts with substance to be found.
Some of the posts are plain wrong too.
Anyway, IMHO and IME most simplistic theories of how people hear are at least partially wrong. That includes Ohm's Acoustic Law as formulated by Helmholtz.
BTW: Dan Cheever, the paper's author, comments in one of the threads: https://www.diyaudio.com/community/...ssonance-the-proper-metric.39942/post-6012329 Cheever's post is followed by one from Earl Geddes.
Anyway, IMHO and IME most simplistic theories of how people hear are at least partially wrong. That includes Ohm's Acoustic Law as formulated by Helmholtz.
BTW: Dan Cheever, the paper's author, comments in one of the threads: https://www.diyaudio.com/community/...ssonance-the-proper-metric.39942/post-6012329 Cheever's post is followed by one from Earl Geddes.
Last edited:
How we hear (and see) is enormously fascinating. Sensing & Perception was a course requirement for my psych degree. I find that many of the audiophile claims around hearing fall apart pretty quickly once you understand how our ears process the auditory information and how the auditory circuits in the brain work.
It gets even more fun when you start thinking about how subjective audio tests are done. Sighted, a small group of friends getting together, etc. Then think about Asch's conformity study from 1951 and how that could play in. Humans, including audiophiles, are social critters...
Tom
It gets even more fun when you start thinking about how subjective audio tests are done. Sighted, a small group of friends getting together, etc. Then think about Asch's conformity study from 1951 and how that could play in. Humans, including audiophiles, are social critters...
Tom
You know there are people who can hear their eyelids click shut?
You know that some of sound perception is through bone conduction, and or through vibration of the body particularly at LF and high SPL? The brain integrates all sensory input, not just from the ears.
Besides, the fact remains that I sorted audio opamps in order of distortion by ear, DBT. As was noted earlier in this thread, once people have formed their opinions, they tend to reject disconfirming evidence out of hand.
Moreover, people are still researching how the audio circuits in the brain work. Don't know when you got your degree but a whole new field of how people hear has emerged which is called Auditory Scene Analysis. At this point nobody fully understands how the brain processes audio, despite what some people may claim. https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2016.00524/full
You know that some of sound perception is through bone conduction, and or through vibration of the body particularly at LF and high SPL? The brain integrates all sensory input, not just from the ears.
Besides, the fact remains that I sorted audio opamps in order of distortion by ear, DBT. As was noted earlier in this thread, once people have formed their opinions, they tend to reject disconfirming evidence out of hand.
Moreover, people are still researching how the audio circuits in the brain work. Don't know when you got your degree but a whole new field of how people hear has emerged which is called Auditory Scene Analysis. At this point nobody fully understands how the brain processes audio, despite what some people may claim. https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2016.00524/full
Last edited:
I'm fairly intelligent, so I would appreciate it if you would stop talking down to me like that.
I've done more than many to educate myself on various topics so that I could have an informed opinion on those topics. You have a different opinion than I. That's great. I'm at peace with that. There are other informed opinions in the universe than mine. I'm at peace with that too.
I just wish you could be at peace with the fact that some of us measure THD, including the THD of capacitors (there! back on topic), and consider those measurements to be meaningful to us even if they aren't meaningful to you. That is all.
Tom
I've done more than many to educate myself on various topics so that I could have an informed opinion on those topics. You have a different opinion than I. That's great. I'm at peace with that. There are other informed opinions in the universe than mine. I'm at peace with that too.
I just wish you could be at peace with the fact that some of us measure THD, including the THD of capacitors (there! back on topic), and consider those measurements to be meaningful to us even if they aren't meaningful to you. That is all.
Tom
I know. Maybe it will help if we both try to keep it more professional all the way around.
This is the sort of thing that is off-putting to me. Makes it sound like you feel smugly superior to all audiophiles, who may actually be hearing more real effects than you think. True, they also make some mistakes, and maybe roughly one-third of them are the stereotypical foolish types. However they are not all wrong, with only you being right.
Out of respect for you, I will send you a PM about some other stuff.
Last edited: