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“Then consciousness is recruited to make sense of an integration that does not come out properly.”I.e. when we hear from speakers what we expect to hear in the nature we don't perceive distortions. But when they differ from what we may expect we pay conscious attention to them.
Probably why Guinness is considered an aphrodisiac in certain countries Is Guinness Stout An Aphrodisiac?
A nice Class D
I have been using Class D stereo Amp with 15W RMS per channel for my desk/computer amplifier. It fits in my pam. Runs of a wall wart - (2A 24V). It sounds really good with floor standing JBL HLS615 speakers - Very good bass very clean mid This amp is offered by http://www.Thinkgeek.com - for $60 - I am afraid JBL HLS615 speakers may not be good enough for this Class D amp!
I use it for playing MP3 files from Pandora -One subscription. It does not have enough gain to work with a LP record player ( You will need a preamp)
I have been using Class D stereo Amp with 15W RMS per channel for my desk/computer amplifier. It fits in my pam. Runs of a wall wart - (2A 24V). It sounds really good with floor standing JBL HLS615 speakers - Very good bass very clean mid This amp is offered by http://www.Thinkgeek.com - for $60 - I am afraid JBL HLS615 speakers may not be good enough for this Class D amp!
I use it for playing MP3 files from Pandora -One subscription. It does not have enough gain to work with a LP record player ( You will need a preamp)
Attachments
Verily, we Hear, yet we do not notice...
I'll add this to this thread, and then later put this in as a separate topic so we can get back to discussions about which amps sound good and why.
This is an open letter for those who insist on pushing the "Measurements only" arguments into every thread on this site, claiming it's only about THD or TIM or (name your favorite here______).
Ummm.... at the risk incurring your wrath, it looks like there's a lot more to it. Turns out the subjectivists may win some portions of this argument after all. And we can prove at least some of it. Scientifically. With info that has been peer reviewed and then published in highly respected Journals.
OK, take deep a breath and read on. You're not going to like this.
Here goes:
Along with measuring HD and THD and TIM, there are almost surely other forms of distortion which we have not yet found ways to define or measure in the reproduction chain. Earl Geddes' HOM for example, or some of the spatial imaging/size/localization distortions.
While there are audible events which are consciously noticed as pleasant or unpleasant, there are others that create subliminal physiological responses... even if "un-detected" on a conscious level.
You see, there's a LOT of signal information that we react to sub-consciously, in ways that are physiologically MEASURABLE....with no conscious recognition of what is happening. Such as HF content beyond 20KHz...and other as-of-yet un-named forms of distortion.
OK, so here's some science that supports this notion; please read the following paper about "super HF" audibility and then let's discuss the conclusions that can inferred:
Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect
In the experiments described, test subjects were asked to identify if a new Pioneer super-tweeter with super steep cutoff slopes, reproducing from 26KHz and up, was audible. They used EEG's on the test subjects, looking for changes in alpha wave production. (Increases in Alpha waves have been shown to be a strong indicator of better health, deeper relaxation, higher creativity, etc. as well as pleasure.)
- The Pioneer tests showed the test subjects had a notable long-term increase of alpha-wave activity when the super-tweeter was playing, even when not consciously detected.
- It ALSO showed a long-term DECREASE in alpha waves when system bandwidth was restricted by removing the super-tweeter. (Listening fatigue?)
- And these differences showed even when the test subjects were unaware the super-tweeter was playing.
Something notable was that some of the subjects strongly defended the notion that they were NOT hearing any difference, even though their EEG's clearly showed otherwise!
Gee, does anyone here think just maybe... if an EEG shows conclusively that people DO react to frequencies in the 20KHz to 100KHz range, (even when they don't take conscious notice)...
Could it then be that an EEG might also show a difference in response when subjects are comparing between cables or amplifiers?
If an EEG or other physiological measurement could show consistent differences in physiological response.... would you still want to categorically assert that it cannot possibly make a difference what cables or what amplifier you use?
How's this for an interesting perspective: double-blind tests are all looking to see if we can CONSCIOUSLY detect the difference... oh-oh...what about the subliminal?
Ladies and Gentlemen: usual double-blind audio testing does not measure any part of the SUBLIMINAL response. Anyone see a flaw in this?
Some would infer that without testing for subliminal response, double-blind testing is USELESS. Yep, or at least pretty flawed.
Now this: we may not be hearing only with our ears !! One of the study's conclusions: "Therefore participation of non-auditory sensory systems such as somatosensory perception also needs to be considered in further investigations."
So if we want to determine which amplifier or cable designs are better, it might be time to start measuring EEG response (and other physiological indicators such as GSR - Galvanometric Skin Resistance - which correlates closely with EEG results) and see how well they correlate with existing amplifier measurements.
When there is the temptation to state something is "inaudible", (such as cables, capacitors, resistors, etc.) it may be wise to re-read the above study and be reminded that even when we are not "consciously noticing" something in the music, we may in fact still be perceiving and subliminally registering the difference in ways that are both physiologically measurable and meaningful.
Who knows? We may in fact be responding to small differences in our local electromagnetic field!
BTW, my background is in EE, and like many, I wanted to believe that what I had learned in school was sufficient, and good enough to explain the world around me. Well, it wasn't.
After a few years studying this issue, I am convinced that if we really want to get a handle on what makes for great sound, we will need to find ways of studying the subliminal response as well as the conscious one. The next frontier in audio is measuring our subliminals. I've been doing some of this with my speakers at HolisticAudio.com, using GSR to see how time/spatial information affects the body, and the results are quite amazing. Turns out that accurate time-response helps create much greater relaxation response, even though it is not "usually noticed" consciously.
Let's coin a new acronym: ===> S.P.D. ===> Subliminally Perceived Distortion
Hmm...what you don't know may actually hurt you!
I'll add this to this thread, and then later put this in as a separate topic so we can get back to discussions about which amps sound good and why.
This is an open letter for those who insist on pushing the "Measurements only" arguments into every thread on this site, claiming it's only about THD or TIM or (name your favorite here______).
Ummm.... at the risk incurring your wrath, it looks like there's a lot more to it. Turns out the subjectivists may win some portions of this argument after all. And we can prove at least some of it. Scientifically. With info that has been peer reviewed and then published in highly respected Journals.
OK, take deep a breath and read on. You're not going to like this.
Here goes:
Along with measuring HD and THD and TIM, there are almost surely other forms of distortion which we have not yet found ways to define or measure in the reproduction chain. Earl Geddes' HOM for example, or some of the spatial imaging/size/localization distortions.
While there are audible events which are consciously noticed as pleasant or unpleasant, there are others that create subliminal physiological responses... even if "un-detected" on a conscious level.
You see, there's a LOT of signal information that we react to sub-consciously, in ways that are physiologically MEASURABLE....with no conscious recognition of what is happening. Such as HF content beyond 20KHz...and other as-of-yet un-named forms of distortion.
OK, so here's some science that supports this notion; please read the following paper about "super HF" audibility and then let's discuss the conclusions that can inferred:
Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect
In the experiments described, test subjects were asked to identify if a new Pioneer super-tweeter with super steep cutoff slopes, reproducing from 26KHz and up, was audible. They used EEG's on the test subjects, looking for changes in alpha wave production. (Increases in Alpha waves have been shown to be a strong indicator of better health, deeper relaxation, higher creativity, etc. as well as pleasure.)
- The Pioneer tests showed the test subjects had a notable long-term increase of alpha-wave activity when the super-tweeter was playing, even when not consciously detected.
- It ALSO showed a long-term DECREASE in alpha waves when system bandwidth was restricted by removing the super-tweeter. (Listening fatigue?)
- And these differences showed even when the test subjects were unaware the super-tweeter was playing.
Something notable was that some of the subjects strongly defended the notion that they were NOT hearing any difference, even though their EEG's clearly showed otherwise!
Gee, does anyone here think just maybe... if an EEG shows conclusively that people DO react to frequencies in the 20KHz to 100KHz range, (even when they don't take conscious notice)...
Could it then be that an EEG might also show a difference in response when subjects are comparing between cables or amplifiers?
If an EEG or other physiological measurement could show consistent differences in physiological response.... would you still want to categorically assert that it cannot possibly make a difference what cables or what amplifier you use?
How's this for an interesting perspective: double-blind tests are all looking to see if we can CONSCIOUSLY detect the difference... oh-oh...what about the subliminal?
Ladies and Gentlemen: usual double-blind audio testing does not measure any part of the SUBLIMINAL response. Anyone see a flaw in this?
Some would infer that without testing for subliminal response, double-blind testing is USELESS. Yep, or at least pretty flawed.
Now this: we may not be hearing only with our ears !! One of the study's conclusions: "Therefore participation of non-auditory sensory systems such as somatosensory perception also needs to be considered in further investigations."
So if we want to determine which amplifier or cable designs are better, it might be time to start measuring EEG response (and other physiological indicators such as GSR - Galvanometric Skin Resistance - which correlates closely with EEG results) and see how well they correlate with existing amplifier measurements.
When there is the temptation to state something is "inaudible", (such as cables, capacitors, resistors, etc.) it may be wise to re-read the above study and be reminded that even when we are not "consciously noticing" something in the music, we may in fact still be perceiving and subliminally registering the difference in ways that are both physiologically measurable and meaningful.
Who knows? We may in fact be responding to small differences in our local electromagnetic field!
BTW, my background is in EE, and like many, I wanted to believe that what I had learned in school was sufficient, and good enough to explain the world around me. Well, it wasn't.
After a few years studying this issue, I am convinced that if we really want to get a handle on what makes for great sound, we will need to find ways of studying the subliminal response as well as the conscious one. The next frontier in audio is measuring our subliminals. I've been doing some of this with my speakers at HolisticAudio.com, using GSR to see how time/spatial information affects the body, and the results are quite amazing. Turns out that accurate time-response helps create much greater relaxation response, even though it is not "usually noticed" consciously.
Let's coin a new acronym: ===> S.P.D. ===> Subliminally Perceived Distortion
Hmm...what you don't know may actually hurt you!
Time to introduce Dan Winter's work about Fractality,the thing that causes gravity and life.Physics that mainstream physicists find hard to accept.😀
It is obvious.
My main criterion is, how often subconscious reactions on sounds happen before the listener remembers that the sound is being reproduced.
Back in the '70s they did a lot of double blind testing and one of the results that stuck out was that people invariably preferred their music played through non-bandlimited ie systems with output well above 20kHz. Sadly that got practically forgotten with the arrival of cds.
The research team that came up with the hypersonic effect in the '90s also relied on double-blind testing and confirmed/explained the results with EEG measurements.
Without blind testing the scientists would have been laughed out of the room when they first presented their results. Without DBTs you got nothing in science.
The research team that came up with the hypersonic effect in the '90s also relied on double-blind testing and confirmed/explained the results with EEG measurements.
Without blind testing the scientists would have been laughed out of the room when they first presented their results. Without DBTs you got nothing in science.
Hi,
Blind testing is an essential scientific tool, but it is subject to the vagaries of expectation bias (aka. Placebo effect), attention deficit/examination stress, fundamental statistics and poor experimental set-up. Anyone wanting to be taken serious will attend to these.
The issue is that much (but not all) of the DB/ABX Testing carried out in the context of audio (especially by the ABX Mafia* in the US) suffered in many if not all areas simultaneously** that it is hard to credit the experimenters with any amount of seriousness*** or fairness, placing their efforts in parallel with mountebanks, illusionists and charlatans of the ilk of the illusionist called "The Great Randi".
It is exactly this kind of pseudo-science that has led to the "subjectivist backlash", which cares to throw out all the science as it's all lies anyway (in their considered view) and thus is doing everyone a great disservice.
Correctly implemented and analysed DB Tests are actually quite sensitive and capable of revealing many interesting things, but as they generally require substantial participation from fairly large numbers of the general public****, decent, low stress environments and processes, a lot of time and thus substantial amounts of funding (compare for example medical research), so they simply do not happen, as no-one wants to fund them.
About the only exception was research into perceptual coding in the 80's and 90's, even the "audio watermarking" DB Tests were seriously bad... Then there was Juergen Ackermann's test for his thesis, the Ultrasonic perception test cited above and then a veritable cornucopia of nothing.
Ciao T
* Clark, Krueger, Carlstrom, Nousaine et al.
** E.g. they where carried out with extremely poor experimental set-up, used subjects with VERY HIGH levels of expectation bias in high stress situations and used numbers so small that any "null results" are subject to a ridiculously low statistic significance, one that is enough to nearly guarantee null results for all but "day & night" stimuli.
*** The only thing seriously pursued was the "debunking" of anything they disagreed with means that while attempting to appear scientific are on closer inspection more linked to confidence frauds than to science.
**** Who will have to be compensated for their time, but have normally no horse in the race and thus low expectation bias.
Blind testing is an essential scientific tool, but it is subject to the vagaries of expectation bias (aka. Placebo effect), attention deficit/examination stress, fundamental statistics and poor experimental set-up. Anyone wanting to be taken serious will attend to these.
The issue is that much (but not all) of the DB/ABX Testing carried out in the context of audio (especially by the ABX Mafia* in the US) suffered in many if not all areas simultaneously** that it is hard to credit the experimenters with any amount of seriousness*** or fairness, placing their efforts in parallel with mountebanks, illusionists and charlatans of the ilk of the illusionist called "The Great Randi".
It is exactly this kind of pseudo-science that has led to the "subjectivist backlash", which cares to throw out all the science as it's all lies anyway (in their considered view) and thus is doing everyone a great disservice.
Correctly implemented and analysed DB Tests are actually quite sensitive and capable of revealing many interesting things, but as they generally require substantial participation from fairly large numbers of the general public****, decent, low stress environments and processes, a lot of time and thus substantial amounts of funding (compare for example medical research), so they simply do not happen, as no-one wants to fund them.
About the only exception was research into perceptual coding in the 80's and 90's, even the "audio watermarking" DB Tests were seriously bad... Then there was Juergen Ackermann's test for his thesis, the Ultrasonic perception test cited above and then a veritable cornucopia of nothing.
Ciao T
* Clark, Krueger, Carlstrom, Nousaine et al.
** E.g. they where carried out with extremely poor experimental set-up, used subjects with VERY HIGH levels of expectation bias in high stress situations and used numbers so small that any "null results" are subject to a ridiculously low statistic significance, one that is enough to nearly guarantee null results for all but "day & night" stimuli.
*** The only thing seriously pursued was the "debunking" of anything they disagreed with means that while attempting to appear scientific are on closer inspection more linked to confidence frauds than to science.
**** Who will have to be compensated for their time, but have normally no horse in the race and thus low expectation bias.
It has been something that I have been meaning to ask though and that is - Those of you that have designed an amplifier (or other piece of kit) that has excellent measured specs, yet you think sounds like rubbish. Do you attribute this poor sound to the low distortion? Or, do you believe that super low THD in itself isn't the cause of the bad sound, it is something else that we've yet to find out?
I can understand how people prefer the sound of some distortion products. But as has been said, going from 0.01% to 0.001% shouldn't affect the audibility of the distortion itself. Here though, those who are mostly against measurements, openly bash THD in a way that appears to say 'if it has low THD it will sound bad'. Do you believe that it's the low THD itself that makes it sound bad, or that it's something else that happens when you strive for low THD?
I can understand how people prefer the sound of some distortion products. But as has been said, going from 0.01% to 0.001% shouldn't affect the audibility of the distortion itself. Here though, those who are mostly against measurements, openly bash THD in a way that appears to say 'if it has low THD it will sound bad'. Do you believe that it's the low THD itself that makes it sound bad, or that it's something else that happens when you strive for low THD?
5th Element;
I have mentioned this before, but extremely low THD has NO bearing on sound quality !
What you designers need to focus on is low ID - this is the source of the "fatiguing" aspect of solid-state alias digitalis sound.
Any THD below about 0.05% is undetectable - try getting real-world ID below 0.1%...
I have mentioned this before, but extremely low THD has NO bearing on sound quality !
What you designers need to focus on is low ID - this is the source of the "fatiguing" aspect of solid-state alias digitalis sound.
Any THD below about 0.05% is undetectable - try getting real-world ID below 0.1%...
Hi,
Low THD in itself is not the cause of bad sound. Technically speaking any live music that is not electrically amplified has zero THD, still, it sounds good.
The issue is that "THD & N" is an arbitrary metric that has no real bearing on sound quality up to points where we would describe it as extremely gross (say > 5% THD at 100dB SPL). It is also trivial to illustrate that IMD caused by "simple THD" is equally inaudible and has little bearing on sound quality again up to levels that we would describe as gross.
So, if there is an audible difference between an amplifier having 0.01% THD & N and one having 0.001% THD & N MUST have a reason other than THD as such.
Note, I am not against measurements as such.
What I object to however, is to ascribe magical properties to measurements that have no foundation in reality, are completely and utterly DISPROVEN to matter, such as the pure advertising myth that "lower rated THD produces better sound" first perpetrated by Marketeer par excellence (et Ingénieur de la médiocrité) Harold Leak when he started to promote his point one series of products.
First, as a rule, I do not belief. Belief or the religious mode of the human mind is of little use to me.
Second, low THD in itself does not make bad sound.
However, to attain low THD we need to use a number of techniques that, I would posit, cause other more subtle forms of distortion to be MAGNIFIED to audibility and that also cause multiplication of HD and IMD orders that sharply magnify audibility of HD/IMD.
As an example, if a multi stage closed feedback loop amplifier has a significant amount of thermal memory* AND high amounts of feedback, we find that inside the feedback loop the levels of signal and distortion become comparable, while in a low feedback or zero looped feedback amplifier the same distortion is orders of magnitude below the signal.
We may speculate on the audible results such a situation may produce, in absence of credible testing we must test ourselves, however inadequate such tests may be and then draw our own conclusions.
Ciao T
* or indeed any other forms of subtle distortions
Low THD in itself is not the cause of bad sound. Technically speaking any live music that is not electrically amplified has zero THD, still, it sounds good.
The issue is that "THD & N" is an arbitrary metric that has no real bearing on sound quality up to points where we would describe it as extremely gross (say > 5% THD at 100dB SPL). It is also trivial to illustrate that IMD caused by "simple THD" is equally inaudible and has little bearing on sound quality again up to levels that we would describe as gross.
So, if there is an audible difference between an amplifier having 0.01% THD & N and one having 0.001% THD & N MUST have a reason other than THD as such.
Note, I am not against measurements as such.
What I object to however, is to ascribe magical properties to measurements that have no foundation in reality, are completely and utterly DISPROVEN to matter, such as the pure advertising myth that "lower rated THD produces better sound" first perpetrated by Marketeer par excellence (et Ingénieur de la médiocrité) Harold Leak when he started to promote his point one series of products.
First, as a rule, I do not belief. Belief or the religious mode of the human mind is of little use to me.
Second, low THD in itself does not make bad sound.
However, to attain low THD we need to use a number of techniques that, I would posit, cause other more subtle forms of distortion to be MAGNIFIED to audibility and that also cause multiplication of HD and IMD orders that sharply magnify audibility of HD/IMD.
As an example, if a multi stage closed feedback loop amplifier has a significant amount of thermal memory* AND high amounts of feedback, we find that inside the feedback loop the levels of signal and distortion become comparable, while in a low feedback or zero looped feedback amplifier the same distortion is orders of magnitude below the signal.
We may speculate on the audible results such a situation may produce, in absence of credible testing we must test ourselves, however inadequate such tests may be and then draw our own conclusions.
Ciao T
* or indeed any other forms of subtle distortions
I would like to quote Hugh Dean's post from another thread which also touches on this issue
Edit: Delighted to see these posts appearing without the usual protagonists being in evidence (yet). I tried to open a discussion along similar lines back a ways with a thread "What can measurements show/not show?" but it got nowhere!
As in everything, it's the details that count. Bland generalisations like low THD or low Jitter cause more confusion & disagreement among the protagonists whereas a detailed & also a holistic view is needed - including also the psychoacoustics aspects.
Edit: Delighted to see these posts appearing without the usual protagonists being in evidence (yet). I tried to open a discussion along similar lines back a ways with a thread "What can measurements show/not show?" but it got nowhere!
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Please explain very carefully how a double blind test can be 'subject to the vagaries of expectation bias' as this does not make any sense whatsoever.
Expectation bias is only possible in sighted tests as far as I can tell.
That is the beauty of DBT: no expectation and relaxed listening as there are no 'right' or 'wrong' answers. I for one feel a lot more relaxed during blind testing than during sighted tests. But then I never claimed to have 'golden ears'. If someone has than of course they would be pooping their pants but that is their problem.
Could it be expectation bias to "not hear any difference"? DBT might address this by setting up a control that has been agreed by the participant to sound different & then putting the control device in with the mix with the other devices in DBT?
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Maybe because we are still doing static distortion measurements that has nothing to do with reproduced music.....
Aren't we awful, the devil incarnate.
I won't bother reposting the perfect null results obtained by some on bandwidth limited (20k) reproduction.
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I prefer low Super-ego in my gear, makes it less self conscious 🙂
How our focus can silence the noisy world around us
Researchers show reduced ability of the aging brain to respond to experience
So its true, you can't teach on old dog new tricks
Hang on that names taken already, at least I thought it was.
23 skidoo
But thou canst not get out by the way thou camest
in. The Way out is THE WAY.
James
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Oops, I spoke too soon but no need to invoke magical thinking in your reply SW - the devil has nothing to do with it.
Maybe this is why Digital amplifiers never caught on - too small & wimpy?
Yes, I'm sure Freud had something to say about people who identified with their equipment as extensions of themselves, particularly equipment that looked seriously dangerous & had big shiny knobs (that could be polished lovingly)🙂
Maybe this is why Digital amplifiers never caught on - too small & wimpy?
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