Misleading Measurements

[pkane2001]

13 hours ago, The Computer Audiophile said:

I was thinking about this the other day and came to the conclusion that measurements are almost always published in a misleading way. Here’s why. 
 

Objectivists believe they know the threshold or level of audibility with respect to measurements. Any anomaly below that level is thus meaningless for people listening to music. It stands to reason that objective leaning people who are truly out to follow the data and help people unearth the truth, should only publish a pass fail style of measurement. 
 

If a component has no issues above the threshold of human hearing, it can only mislead people if these measurements are published. Components without issues should be given a stamp of approval and that’s it, if the true goal was objective info and to stop people from wasting money like is so often said. 
 

I would love to know why objective people are interested in anything below the threshold of human hearing and why they are interested in this info given that it can cause the same issues they rail against with respect to subjective opinions. 
 

Perhaps I should ask @Archimago why he publishes measurements below the threshold of human hearing. 

 

Chris, perhaps it's hard to believe, but not every objectivist is the same. We don't all think the same way and believe the same things.

 

As an example, @Archimago and I just ran a blind test to determine audibility of harmonic distortion. We ran it not because we believed it was inaudible at -50dB or audible to the -200dB level (as some in the industry will claim), but because we wanted to find out.

 

There's a large contingent on ASR that will tell you that harmonic distortion at -120dB is much better than -115dB. In an engineering sense, this is true: lower distortion is more transparent than higher, more 'pure'. But is this difference really audible? And could it be that we, audiophiles, prefer a little distortion to none?  That's why it's important to study these things, and running tests and experiments is the way to do this.

 

Proper engineering has a lot to do with lowering distortions and producing better measurements, even when these are well below audibility. Some of us prefer better engineered products, especially if they are less expensive than some high-end ones that are engineered poorly. Measurements are the way to determine this. Not if it sounds better, but if the design is sound and engineering is done well.

 

The point of doing measurements is that they allow anyone to interpret the results based on their knowledge and understanding, which may change over time. Measurements do not include bias and personal opinion. I know you take issue with Amir's subjective recommendations. I do too. I don't find them useful, as I don't believe he's completely free of bias (no one is). But his measurements are, and this is confirmed by others producing the same results.

[pkane2001]

19 minutes ago, The Computer Audiophile said:

Hi Paul, thanks for the thoughtful comments. 

 

As you can imagine, I see this differently, not with respect to your opinions of course, but with the efficacy of some measurements in light of the objectivist party line that berates audiophiles for talking about stuff that they believe can't be heard. I just don't see how objective leaning people can have it both ways, with a straight face. 

 

Objectivists often hate discussions of things like USB cables, claiming there are no measurements that can show a difference between them. The discussion often includes that these cables are bad for the industry, scare people away and mislead people into purchasing stuff they don't need. 

 

I see the discussion of inaudible measurements as being the other side of that coin. A DAC that measures -130 dB is worse than a DAC that measures at -131 dB. The better measuring DAC will be put on a pedestal and listed at the #1 DAC. This will no doubt cause people to purchase the DAC over others that may measure at -129 dB, -128 dB etc... It's human nature and there's no getting around it. 

 

Personally I don't mind the measurements and think adults can make up their own minds and purchase what they want. It just irks me that objectivists, who have goals other than looking at graphs to satisfy themselves, eschew one thing they claim is inaudible but consider the other inaudible items laudable. 

 

If we are solely talking about engineering feats of something like the lowest noise floor, then by all means show the measurements. But, that reminds me of the car audio competitions for the loudest sounds within the cabin of the car. What's the point. I suppose some people could purchase equipment for reasons other than listening and that's OK, but

 

Surely the audibility of jitter is something that objectivists can agree on. There must be a generally accepted number, below which is inaudible. Take that number and go lower by 10%. All jitter measurements below that shouldn't matter and can only serve to mislead people, if the accepted party line of objectivists is true and inaudible stuff doesn't matter. Thus, showing a pass fail for jitter should be the prudent way to display this info. 

 

Note: I'm not arguing for this position. I'm only pointing out what I see as a double standard and I'm seeking to understand why it's pushed so hard.

 

Well, audibility thresholds are not some voodoo magic, they are not a new concept. These can be (and have been) studied. I myself invested a lot of time and effort to create tools to aid in such studies. I wouldn't waste my time if I believed that everything is known and there's nothing new to learn in this space.

 

24 minutes ago, The Computer Audiophile said:

It just irks me that objectivists, who have goals other than looking at graphs to satisfy themselves, eschew one thing they claim is inaudible but consider the other inaudible items laudable. 

 

There's no accounting for tastes or preferences. A "true objectivist", if such a thing exists, would question any claims of audibility/inaudibility and look for real evidence to demonstrate that there is a correlation between some measurement and audibility, as well as measurements and preferences. Many of the papers I cite on the BIAS in Testing thread are designed to study exactly this.

 

33 minutes ago, The Computer Audiophile said:

if the reason for components is to listen, then it makes zero sense to care about that which is inaudible

 

Agreed!

 

 

[pkane2001]

6 minutes ago, The Computer Audiophile said:

Please help me understand rather than just complain. 

 

If we all posted all the caveats and possibilities, there's be nothing worth reading. For example, objectivists who love measurements, except those who like them and don't view them as the end all be all, and except those who only go by measurements, and except those who only love some of them, and except those who continue to do experiments themselves, etc... 

 

It gets pointless. We have to have some leeway when writing and reading that allowed people to discuss topics without carving out exceptions for all possibilities. 

 

I'm not at all complaining about this thread, I like the ability to have a rational discussion. But, I've experienced over and over again this attempt to lump all the objectivists into a single straw-man, with all the extreme views rolled into one. As if we are all one individual and all think the same. I assume that's what @kumakuma is reacting to. Perhaps it's human nature, because I see the same occurring on ASR, but in the opposite direction.

[pkane2001]

5 minutes ago, The Computer Audiophile said:

I just don't understand why objectivists love some inaudible aspects of this hobby and eschew others. 

 

Beats me . It's irrational.

 

[pkane2001]

27 minutes ago, Currawong said:

I think that much of the problem with noisy, online "objectivist" talk is that it is based on a lack of genuine knowledge of what measurements show. I've noticed a recent trend for hyped Chinese DACs to show their low SINAD numbers, yet avoid showing the measurements of their leaky filters. The problem with both is that neither have their relation, if any, to what we actually hear explained. 

 

For example, how often do you read about the effect of digital filters on our perception of soundstage?  The claims regarding the effects of distortion down to -200dB were specifically related to this.  While running a file-based blind test to determine blatant audibility is interesting, basing it on comments/claims which are related to specific hardware is not the same thing.

 

What is more, I think the contradiction between "objectivists" seeming to claim distortion differences are inaudible one minute, and the next minute complaining about inaudible side-bands on SINAD tests, comes down to a significant number of them wanting to be part of the bandwagon, and blindly following whatever their at-the-moment chosen leader is saying, without having any actual knowledge themselves, let alone a desire to consider the blatant contradictions in their their beliefs. 

 

A major issue, which I have given an example above in my wording in the paragraph above, and I think which Chris' original post is also a good example of, is attachment to the same, repeated, simplistic ideas about both audio science and people, starting with the idea of anything, whether it be a measurement artefact or changing a physical product, being straight-up audible or inaudible, as with the huge variety of electronics and music we have available to us, as well as the complexity of it, these things clearly cannot be declared as absolutes using numbers.

Could you conceive that there are some objectivists that actually understand measurements, SINAD, jitter, filters, clocks, phase noise, etc, or are they all just ignorant? This being an objective forum, I’d like to see some objective evidence for your statement.

[pkane2001]

59 minutes ago, JoshM said:

I’m interested in measurements to catch major issues and to understand why we’re hearing what we’re hearing. I’m not interested in them as an arms race with no meaningful purpose. 

 

I agree 100%.

 

[pkane2001]

2 minutes ago, The Computer Audiophile said:

 Paul says it has existed for quite a while. 

 

I'm losing track of what we are talking about. What data? Audibility thresholds? Of course this exists.

[pkane2001]

14 minutes ago, The Computer Audiophile said:

Yes. Audibility thresholds. 

 

This may be a good start, as a summary:

 

http://www.aes-media.org/sections/pnw/ppt/other/limitsofhearing.ppt

 

 

 

 

 

 

 

 

[pkane2001]

18 minutes ago, JoshM said:

I followed the ASR attempt to establish agreed upon thresholds for a while, and it seems like it petered out. My sense of why that happened is that we can mean “audibility threshold” in two different senses: what humans physiologically can detect and what research has established listeners hear in audio reproduction. For example, the audibility threshold of distortion was stricter in the initial ASR threshold attempt than in Archimago’s recent experiment. So, over at ASR there seemed to be a mix of physiology, AES-type research, and random assertions used to support the “lenient” and “strict” thresholds. 
 

Some of the results, such as a “strict” linearity of 120 seemed far beyond realistic audibility IMHO. At the same time, I kind of think IMD is more audible than that ASR post suggested. However, it definitely seems like there’s a lack of good research on some topics.
 

Then, of course, we’d get into issues of age and hearing and trainer versus untrained listeners.

 

Ultimately, this uncertainty and complexity is why I think a lot of people default to the “moar is better” approach. But I think a “these DACs all clear the bar of flat FR, linearity to 90 dBfs etc., so I’m going to listen to them and see if I notice any differences and which I like better” is more advisable. 

 

The threshold thread was a bit convoluted and used data from mixed sources, including, as an example, the opinions posted by NwAvGuy. It was a good start, but it certainly did not define hard limits that would be acceptable to everyone, more like guidelines to get you started.

 

IMD/HD limits were recently tested by @Archimago in a blind test. A small percentage scored perfectly (not to brag, but I was one of them). 

 

Age-related hearing deterioration is absolutely something that should be tested if one is interested in audibility thresholds. A few years ago I wrote a quick-and-dirty program to let me measure my own hearing across the 20-20k frequency spectrum. Mine turned out to be worse than the ISO average by a small margin, but better than average for my age group.

 

One of the reasons I've been building software to simulate various levels of different types of distortions is to let me, and those who are interested, do the testing themselves. It doesn't help me if I know that someone out there can hear out past 20kHz if my hearing range is limited to 16k. I'd rather know my own thresholds than some published average or a statistical distribution from testing of some group.

 

 

[pkane2001]

1 hour ago, yamamoto2002 said:

 

You may be relieved to hear there is only Do, Do♯, Re and Re♯ between 16kHz to 20kHz

 

14,080Hz A    La
14,917Hz B(A♯)  La♯
15,804Hz H    Si
16,744Hz C    Do
17,739Hz C♯  Do♯
18,794Hz D    Re
19,912Hz D♯  Re♯
21,096Hz E    Mi
22,350Hz F    Fa
23,679Hz F♯  Fa♯
25,087Hz G    Sol
26,579Hz G♯   Sol♯
28,160Hz A     La

 

That's good news! 

[pkane2001]

49 minutes ago, John Dyson said:

I have been thinking (honestly) about the matter of comparing sample rates, and how people DO sometimes hear differences.  Was thinking about errors in the experiments, and one error that seems to be very easy to make -- using not-linear phase filters in the conversions.  Let me explain:

 

The difference between say, minimum phase and linear phase isn't the wiggles that move around on square waves, but more the delay at low frequencies is very different than high frequencies on a minimum (or intermediate) phase filter.  This means that significant timing differences encroach into the audible spectrum.   The ONLY kind of filter where the delays are constant and the signal will remain maximally unmodified is a constant delay filter.  That means, 'linear phase'.

 

I haven't looked at any experiment in detail, because there are usually far more details missing than let any real evaluation be done.   As soon as 'software in a box' is used, I am not 100% sure that I trust its technical accuracy.   Anyway -- that is off topic,  it seems like there is a common 'tone control' (:-)) used by some audio people, choosing between linear phase, minimum phase and intermediate phase filter regimes.

 

An experiment about sample rates cannot be very consistent without using constant delay filters.   That doesn't mean, when all is said and done, the 'filter of choice' wont be used after the experiment.  But as soon as the delays are variable, then the results are in question when comparing the audibility of sample rates.   Again, after the experiment, use the filter choices that 'sound good' -- but the only way to do the experiments with not-linear-phase filters is to make sure that the delays are consistent between filter choices.

 

John

 

I didn't score well on the HD-Audio Challenge by Mark Waldrep, as an example. But I know a few others who scored perfectly, so there's something related to hi-res encoding or its playback that can possibly make these audible. I doubt that it has anything to do with the frequency response caused by the increased sampling rate between 44.1kHz and 96kHz. But then, the question is what is it? Is it the filter? The resampling in the DAC or the reconstruction filter? IMD with higher-frequency signals? Or are some ears just more sensitive to it than mine (I've no doubt that's true)? The reports of someone having useful hearing at 23kHz as an adult are possible, but very unlikely.

 

Here is a study result based on 384 test subjects of various ages. You'll note that the level of sound at 20kHz needs to be over 90dB to be detectable for age group 22-35 (and no, I'm not even remotely close to that age group!) The error bands go down to about 85dB level, so not much variation. I don't think I'd ever want to listen to a recording that had 90dB content above 20kHz:

 

[pkane2001]

3 minutes ago, John Dyson said:

One thing that I'll do when I get a chance, actually create a table of delay vs frequency for various minimum phase filters -- I am truly not sure the effect, but the difference between DIFFERENT minimum phase filters can create audible differences (theoretically.)

 

My guess that the differences that people hear, and whether or not they hear differences is based upon time resolution of the hearing at audible frequencies, not so much the higher sample rate/Nyquist frequency per se.  Also, don't mistake my comment about sample rate -- it has little to do with the time resolution, as long as there is enough bit resolution.  (It is all about maximum information content.)

 

There is NOTHING wrong with using minimum phase filters if that is what 'sounds good', but for an experiment -- but I believe that filter delay vs. frequency will easily bias the results.   I would ONLY use carefully crafted software for testing purposes also -- not something 'off the shelf.'.  The reason isn't that other DSP software developers aren't competent, but on the other hand, the design might not have considered things that are important in the experiment.

 

I remember a kid when I was in high school was passing hearing tests at impossibly low levels because he was hearing the hiss in the electronics as it was gating on and off.  These measurements must be done with a scientific mentality, not just scientific/good experimental discipline.   As I tell everyone on some of these things 'There be dragons'.

 

John

 

 

I've been meaning to add adjustable filters (minimum and linear phase) to DISTORT app for comparison and audibility testing. At some point, I'm hoping to make it easy to compare the effect of any filter(s) on any sound track. But based on my current workload, probably not any time soon

 

[pkane2001]

3 minutes ago, ray-dude said:

 

I suspect it is differing levels of phase/timing sensitivity.  I'm definitely a phase/point source guy (on steroids) and have optimized my system around same. I've noted that when folks come over, some people are definitely more WOW for phase-related optimizations, and others barely hear them at all.  The later group seems to be more power/amplitude focused.  Some folks fall somewhere in between.

 

I guess the question is what phase differences are we talking about? A linear filter, by definition, will only introduce a constant delay. That same delay will be in both stereo channels, so the effect is inaudible while the music is playing. Unless you need to sync playback to video or to other devices that have a different delay, a linear filter shouldn't cause any phase issues. Of course, a filter could be poorly implemented, or some devices may use non-linear filters. In those case, I think it'll be worth testing for the audibility of the phase differences.

[pkane2001]

1 hour ago, ray-dude said:

As a practical matter, in my room, ~1mm changes in speaker position is audible for me in this (very) artificial scenario (and since this is an objective forum, distance from my listening position to the same position on speaker drivers confirmed to be identical to within the ~2mm resolution of my laser measure

 

You do realize that you'll need to keep your head to ~1mm exact position in order to keep this precise phase alignment? Do you use a head vise? 😎

 

1 hour ago, ray-dude said:

If we were to naively translate that to frequency, at the speed of sound that implies ~340kHz hearing resolution.  My 53 year old ears tap out around 15kHz and clearly can not hear >300kHz tones.  However, I can hear phase timing differences with that level of signal timing resolution, in this (very) artificial scenario.  With a better treated room, I'm sure things would be much better still.

 

Actually, timing resolution has little to do with sampling frequency. A 44.1kHz/16bit redbook CD standard is fully capable of resolving timing differences well below 1µs, and higher resolution has more to do with the number of bits than the sampling frequency. Meanwhile, the lowest audible interaural time difference (ITD) reported in literature is 10µs, in other words, well within the capabilities of the redbook standard.

 

1 hour ago, ray-dude said:

For me, higher resolution sources (whether natively recorded or reconstructed with a sinc reconstruction function) has been about phase timing accuracy, not audibility of the ultra high frequencies.  Depending on the recording chain and performance of the components, that phase resolution may or may not matter obviously.

 

I understand your preference for hi-res, but I'm afraid it's not needed for higher phase resolution. 

 

 

 

[pkane2001]

1 hour ago, ray-dude said:

 

The head vice would be fabricated out of panzeholz   For the spirit of this anecdote, I was trying to share what is detectable, (thankfully) not how I listen.  FWIW, it is angular distance from the driver.  That is a LOT of lateral head position to have 1mm impact on distance to driver (at 9' listening distance, ~3" if I did my math right?).   My head twist variance is absolutely more than 1mm, agreed.  Interestingly, I find that my head position naturally gravitates to where the soundstage is most expansive and natural (or in the case of the pink noise scenario, where the null is more pronounced)

 

To the ITD, you are certainly better read on this than I am, but isn't that related to localization of sound source by the time difference it takes for sound to get to each ear?  With stereo music reproduction, we actually don't want to hear the speaker driver, we want a sound stage projected before us.  My phase analogies were related to that sound stage projection, not localizing where a speaker may be.  

 

That being said, I am google-level ignorant on the ITD measures.  I have no idea if the psycho acoustics are the same mechanism between ITD for sound source localization, and reconstructing a sound scape from the aggregate phases of the sounds we are hearing.  I suspect our brains are doing a lot of interpolation/projection for the later functions, just because our brains are really good at casting things in a way where it is easier to digest/interpret (Coltrane obviously isn't standing in front of me, but damn does my brain gets a lot of juice when it sounds like he is...sign me up for more of that kind of self-delusion!).

 

 

 

ITD is one way that the brain determines the left-right direction of sound, ILD (interaural level difference, aka IID) is the other. Reverb is another mechanism used to help the brain determine the depth of the sound-source position.

 

Realistic reconstruction of a complex soundscape with precise object placement is a much more complex topic that involves head tracking, head-related transfer function (HRTF), reflections/reverb, dynamic frequency effects, as well as ITD and ILD. Simple two channel/two speaker stereo can't reproduce a complex soundscape in a truly believable fashion.

 

ITD is related to phase, ILD to amplitude. In mastering recordings, primarily ILD is used to place individual recorded microphone sounds left-to-right, as it is much easier to produce and adjust.

 

[pkane2001]

Just now, fas42 said:

 

That's the book learnin' explanation - but is not the reality. Anyone who has managed to evolve audio playback to the necessary quality knows what happens - it's quite trivial for an immensely complex soundscape to be perceived as being truly believable, at this standard of SQ.

 

Sorry, Frank, but that's false. Not just from books, but from my own experience. If you've not heard a properly instrumented 3-D audio with HRTF adjustment and head tracking, you should try it. There's no comparison to your "imagined" soundscape.

[pkane2001]

44 minutes ago, fas42 said:

 

Don't you appreciate that there are multiple ways "for the mind to be tricked"? It can be done with the deliberately manipulated process you mentioned - or by having the clues available by a very high standard of playback. The soundscapes "inside the skull" are the same - if your mind decides that what you hear is the "real thing" then it hangs on to the illusion; and won't give it up readily ... you see, everything is "imagined" - our minds, internally, don't put instances "created by science" on a pedestal.

 

I do, and I also know that each mind and ear combination is different. When you claim you hear "realistic" soundscape it means absolutely nothing to me, since I don't know what it takes to trick your mind into believing something like this. Maybe your imagination is much better than mine. Or maybe your definition of realistic is not the same as mine. Or maybe your brain never adjusted to use your HRTF for sound location and compensated by using some other method, maybe ITD/ILD only. Or...? I can't see (or hear) into your mind Frank, so I can't tell what you can hear and what is enough to fool you.

 

With my system, I hear a very good approximation to a soundstage with very good tonal reproduction, with excellent dynamics. I hear depth and position of instruments, and I enjoy it immensely,  and have for about 20 years with only minor changes. And yet, it's not producing a real soundscape. I only occasionally (and mostly on binaural content) hear voices and noises that startle me, surprise me to the point of thinking it's coming from inside the house rather than from the audio system. I almost never hear the sound coming from my speakers, unless the sound is panned to be exactly at the speaker position. Most of the left-to-right sounds come from in between, with some coming outside the speakers. The soundstage depth is amazing on some content, and goes a bit in front of the speakers on other. But sounds never get close to me. They never envelope me to the degree that I can move my head around and feel like I'm there. That's what proper 3-D soundscape reconstruction does. It's the difference between a very good 2-D photograph and the 3-D world. At least to me.

 

 

[pkane2001]

10 minutes ago, fas42 said:

Other people around me have appreciated the difference it made - which confirmed that I was not alone in hearing this ... people who couldn't give a damn about audiophile concerns just enjoyed listening to it; it "ticked the boxes".

 

I've had plenty of people say they love my system over the years. A few actually became audiophiles after listening to it, so you could say that it ticked at least some of the boxes. I'm not sure that proves anything 🤷‍♂️ 

 

I see that Alex is getting upset that we are veering off topic, so I'll stop here

 

 

[pkane2001]

6 hours ago, Audiophile Neuroscience said:

 

I seem to recall it was about

Quote

Perhaps I should ask @Archimago why he publishes measurements below the threshold of human hearing. 

 

 

Why does @Archimago publish measurements below the threshold? Could it be that many devices actually fall below this threshold with their distortion levels? I can say that he not only mentions the audibility thresholds in his reviews and measurements, but also runs public blind tests to try to get some objective data on how and what we can hear.

 

Just listing from memory some of his recent blind tests: Harmonic Distortion, MQA, digital players, linear vs minimum phase filters, hires vs redbook, LP vs digital, ... Regardless of what you think his philosophy is, his tests, procedures, results and analysis are all publicly available for review and comment. Others can easily reproduce the same tests if they want to prove him wrong (or right). That's the objective approach.

 

[pkane2001]

1 minute ago, The Computer Audiophile said:

What’s the goal of telling a consumer that even though he can’t here the difference between DAC A or B, DAC A has a much better score? And, at the same time telling a consumer that he can’t here high resolution audio so it doesn’t matter?

 

The goal is simple: let the consumer pick a device based on features, build quality, engineering, price, esthetics, etc. As long as the consumers are aware that there's no audible difference, they can concentrate on other qualities that matter to them. There's no double standard in @Archimago's work, as far as I can see.

[pkane2001]

4 minutes ago, The Computer Audiophile said:

 

What about USB cables? Do you put them into the same category as DACs if all the cables and DACs have no differences above the threshold of human hearing? 

 

Can you please show me where the highlighted statement has been made and why do you think that all objectivists think this? Of course there are poorly designed DACs and badly constructed cables that cause obvious, likely audible, distortions and errors.  That's why measurements are useful.

 

Armed with some knowledge about distortion audibility and with detailed measurements of a device, anyone can decide for themselves whether the device is fit for their consideration. I wouldn't consider a DAC with THD of 0.1% as transparent, for example.

[pkane2001]

8 minutes ago, The Computer Audiophile said:

Hi Paul, I think I used the wrong terms in my question. I don't think anyone has ever said it how I wrote it. That was my mistake.

 

I'll rephrase my question.

 

What about USB cables? Do you put them into the same category as DACs if the cables and measured DACs have no anomolies above the threshold of human hearing? 

 

Hi Chris,

 

USB cables introduce a lot less variability into the overall playback chain than the DAC, the analog stage, the amp, and especially the transducer, speakers or headphones. Usually this is well below the threshold of audibility. I've seen a few broken USB cables that caused obvious errors, but a cable that conforms to USB spec should just work.

[pkane2001]

16 minutes ago, The Computer Audiophile said:

I hear what you're saying, but a DAC that measures below the threshold of human hearing must also be in that "should just work" category correct?

 

Correct. But there are many more opportunities to mess up a DAC than a USB cable.

[pkane2001]

20 minutes ago, John Dyson said:

You really do seem like a measure twice, cut once type person, and that is good.   Tweak tweak tweak, on the other hand, wastes a lot of potentially productive time.  None of us has lots of time to spend tweaking, when there might be good alternatives.  Some situations REQUIRE tweaking, but no-one should seek out the circumstance -- because,  in worse-than-trivial situations, becomes a game of frustrating whack a mole.   At first, 'whack a mole' can be fun, but after trying to deal with more than a few variables, the multi-dimensional optimization -- where dealing with analytical/complex math -- the optmization starts being less and less intuitive, VERY QUICKLY.

 

I'd suspect that people with experience using both general techniques would counsel people to try to 'measure twice', which at first requires a little more learning and study, but the results are well worth it.

 

A good analogy is Thomas A Edison (some really old, exploitative, but persistent guy that one of my first bosses knew and worked for), where he spent huge amounts of time 'tweak tweak tweak', but this little guy named Tesla blew Edison away once technology required some actual intellectual study and learning.   If Mr 'tweak tweak tweak' Edison had his way, then electrical power distribution would have been deployed with generation stations on every several city blocks, and NO power distribution in the countryside.   Edisons weak, tweak tweak tweak technique was fortunately deployed only in limited situations before being replaced.   Edison's intellectual arguments consisted of electrocuting animals.  :-).   His economic arguments were done by his early supporter, JP Morgan.  Thank goodness, brute force, force-of-will and hard-core financial might did NOT win in this case.

 

Tweak-tweak-tweak works okay in primitive situations -- but in more complex multi-dimensional situations (almost all EE/DSP stuff is like that), can become a misguided allocation of time.  A little learning/planning ahead of time, in many simple applied technology cases (home audio systems) are well worth the investment.

 

Many of you know that I am in tweak tweak tweak hell right now -- and I would never counsel any friend of mine to use the design-by-tweak technique for any complex project at all.

 

John

 

 

You're right John. I dislike tweaking. I do it out of necessity, when I need to understand some puzzling behavior, I guess you could call it "experimenting". Then, I tweak, sometimes randomly, until I figure out the cause and the reason for why it works the way it does. Once I understand the real fix, I discard the tweak. It'll keep gnawing at me if I find a tweak that  I can't understand or explain, and I'll have to keep digging, sometimes for weeks, into one particular issue until I get the answer.

[pkane2001]

3 hours ago, Audiophile Neuroscience said:

 

Hold the phone, is not the number of opportunities to mess up irrelevant? If in fact the DUT measures below the threshold of human hearing it "should just work" in that range below the threshold of human hearing, isn't that the assertion? So why report it is the question being asked. Things like price, aesthetics, build quality, and performance in the audible range are independent factors that people can use to guide purchase.

Already answered all of that.