Popular Post Audiophile Neuroscience Posted February 22, 2020 Popular Post Share Posted February 22, 2020 I think the OP poses one of the great perennial questions in audio/music perception……when do measurements correlate with subjective impressions? I think if we knew the answer to this it would solve a lot of disputes. More importantly, I'm just plain curious to find out the answers. I could be wrong but what I have so far taken from this thread and several others like it, is that there is no firm objective scientific rules that apply. At the heart of the question of any correlation is whether there is an association or link between the level or magnitude of measurement/variable A and the magnitude of measurement/variable B moving in the same (or reverse) direction. If you chuck in concordance which is basically the extent of how the levels of the two measurements match i.e. their agreement or sameness between levels and/or their reproducibility, you then have a meaningful association. This of course does not mean a causal relationship necessarily. So, where I am leading with this is, is there any measurement that correlates and is concordant with a particular sensory audio perception? We know for example (or at least I have read and have had some experience) that speaker directivity and room reflectiveness will affect imaging in certain predictable ways for most observers. There are measurements for these things but are there predictive values that will hold true for most people? There has been some talk of degrees of various distortion measurements, jitter, which may be perceptible and at different sensitivity levels for different people and different levels of training etc. Again, are there predictive values that reproducibly hold true for most people about what the subjective correlate sounds like? Is it just that it somehow makes things sound irritating in ways that are hard to define? Somehow a little less natural, organic or less "real". On the other hand some distortions appear to make things sound subjectively better, at least to some. In the case of tube distortions at least there seems to be some reproducible and shared subjective correlate, namely "warmth" or similar description. To paraphrase the OP question, what do any of these measurements tell us about what the music sounds like? Do any of them have predictive value for perception and in what way? Iving and Confused 1 1 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted February 23, 2020 Share Posted February 23, 2020 2 hours ago, fas42 said: It may not be "jitter" per se, but my modus operandi for decades has been to just listen to a rig, and wait for "things (that) sound irritating in ways that are hard to define", which immediately translates to the SQ being "less natural, organic or less "real"". My point would be, which is a better use of my time? To go to great effort to extract some number, by some means, which is an exact correlate of what I'm registering - or, merely correct the causal factor ... so far, the latter has won out ... Hi Frank, your "MO" is well known and i dare say not dissimilar to what most other audiophiles do. I agree that if you can fix the cause of the problem then probably no need to measure it. I already do this by placing for example tube traps in corners of the room. I could measure the resonances but I already have a fair idea of what they will be and where they will be and a number will not likely change where I locate a tube trap. None of this however addresses the OP question.When (and what) measurements correlate with subjective listening impression? I would love to know the answer. My crude impression is that measurements tell us that the item is operating to spec, whatever those parameters are.They tell us how they will interact and may be suitable to perform with other devices, like is there enough current to drive difficult speakers or will there be impedance mismatching etc etc. No doubt these things have impact on SQ. But still, what are the measurements that correlate with perceived sound characteristics? Iving 1 Sound Minds Mind Sound Link to comment
Popular Post Audiophile Neuroscience Posted February 23, 2020 Popular Post Share Posted February 23, 2020 3 hours ago, Archimago said: Great discussion AN. I think it's worth remembering that to some extent, it's going to be very difficult to find firm rules beyond population "norms" due to the variability of auditory acuity. To be even more accurate, we would need norms for gender and the effect of age. All of this would need to be done on large populations as a result... Very much like neuropsychological test result interpretation. By necessity, this will also require controlled blind testing. Yes, very reasonable. Again, who's going to do this? We do know from the literature over the years that there have been sophisticated systems developed to try to determine correlation between distortion and perception. For example, here's a presentation using a neural network model to calculate a "perceptual distortion index" or "PTHD" to model distortion audibility. Toole and Olive's work on the speaker "spinorama" is another example of correlating blind listening with measurements. You should enjoy Toole's Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms. I'm totally with you in this question and the desire for understanding these correlations between objective measurements and subjective perception is very important. The only way this can be answered is with lots of blind testing. Ultimately, I think this needs to happen in the academic space, not in the hobby arena especially with strongly "subjectivist" audiophiles. When so many are against even the importance of doing blind tests, and magazines produce articles about how they're "flawed", how can we "culturally" even begin any meaningful research? Thanks Archimago I have the Floyd Toole publication. Thanks for the semantic scholar PDF, I will take a look. I am likely going to disappoint you now by declaring I'm not a fan of the reliability of blind testing in the audio setting. I would never argue against the necessity of eliminating the obvious bias, just the problem of introducing interdependent variables in the process, thus making the test unreliable. I believe there is a propensity for false negatives and this has been borne out to some extent in the literature. However, let's certainly not go into the pros and cons of blind testing. At the end of the day I am basically reinforcing what you said that this kind of research, including properly conducted blind testing, is best done in the academic domain. I think it is very difficult to do properly conducted blind testing. The problem here is that it is unlikely that academic institutions will be interested or have funding to do such research. All that said it still surprises me that we haven't been able to come with more measurements that correlate to subjective listening impressions. Apart from some speaker examples I can only think of one other example off the top of my head. That would be the various measures of dynamic range and correlating that to descriptions of "compressed sound". Cheers David sandyk, Bill Brown, Iving and 2 others 4 1 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted February 23, 2020 Share Posted February 23, 2020 6 minutes ago, semente said: Measurements quantify particular parameters of reproduction. They are deemed good or bad in relation to the accuracy with which the signal is being "handled". Some measurements are bad from a fidelity perspective but the offending distortions sound good (euphonic) to some people. Whether good measurements sound good or not depends on the listener's preference regarding presentation: it's a matter of taste. Hi Ricardo Agreed. To my my way of thinking, If accurate measurements quantify what the test procedure is designed to look for. What happens from there is interpretation of the result. It is important that they measure what you think they are measuring and mean what you think they mean. I also believe that "not everything that can be counted counts and not everything that counts can be counted." Bill Brown 1 Sound Minds Mind Sound Link to comment
Popular Post Audiophile Neuroscience Posted February 23, 2020 Popular Post Share Posted February 23, 2020 2 minutes ago, tapatrick said: When I am on the move I stream through an iphone via bluetooth to Sony WH-1000X headphones. I've noticed how in some ways I enjoy the music more as a whole, even though it has less detail, has a small 'in your head' stage and a more rounded sound compared to my main system which is much more revealing. I enjoy listening at home for the subtle nuances and cues which are revealed and a more realistic illusion of live music and voices. This issue of artefacts that do not exist in nature must be a key factor in achieving a natural sound (or not) while pursuing ever more information from digital recordings. Hi tapatrick, I have always said I enjoy some music better on a car radio than on a high end audio system. My take on this has been poorly recorded music will always sound more palatable when squashed down,compressed, truncated and less resolved. The brain given the main thrust of the melody and rhythm , without the annoying distractions, can fill in the missing bits to make it an enjoyable experience. This is especially true for familiar music. I believe a similar phenomenon happens with partial hearing loss. The brain steps up to fill in the blanks. Some may think of this an an illusion. I think of it as Perception not Deception. sandyk, Teresa, ferenc and 1 other 3 1 Sound Minds Mind Sound Link to comment
Popular Post Audiophile Neuroscience Posted February 23, 2020 Popular Post Share Posted February 23, 2020 4 hours ago, tapatrick said: I presume this is also due to the absence of these 'unnatural artefacts' which may come along with advanced digital audio i.e. more detail and resolution etc. Don't get me wrong, my home system is very enjoyable but even at live concerts with amplified sound i.e. voices I usually find this a tad unnatural... Quite possibly the "unnatural artefacts" have been accentuated as you suspect. I generally subscribe to the GIGO (garbage in garbage out) principle, High Rez crap recordings sound like highly resolved crap 🤣. Not everyone is with me on this one. Certainly and OTOH a good sound system will potentially bring out the best in less than perfect recordings. Its like rediscovering new songs.Some of the 50's and 60's recordings are glorious. Bill Brown, sandyk and tapatrick 3 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted February 23, 2020 Share Posted February 23, 2020 6 hours ago, Jud said: By the way - there are just acres and acres of possibly relevant academic psychoacoustic research into potentially relevant topics, Hi Jud Agreed there are acres of psychoacoustic and pschophysics papers. Do you have any references for the OP question? Cheers David Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted February 23, 2020 Share Posted February 23, 2020 1 hour ago, Bill Brown said: . I should probably sign out soon also. I have never written this much on a forum in my life! Hi Bill fear not my friend , I think your post tally has been stuck on 115 for some years,lol....no one will ever know how much you post.🤣 Ive always liked your posts ever since those IIRC "water cooler" days when an objectivist invited me to have a water cooler chat with my doctor colleagues regarding my objection to (his) bullying behaviour. You volunteered you actually had the chat with a psychiatrist colleague over lunch and the response was priceless ! Bill Brown 1 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted February 24, 2020 Share Posted February 24, 2020 1 hour ago, Bill Brown said: Thank you; good memory. Though we have to recall that not all felt the same. I was accused of diagnosing inappropriately and labeled "ethically challenged." From what I have seen to date there has been no grounds to ever doubt your ethics, quite the reverse.😃 Bill Brown 1 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted March 7, 2020 Share Posted March 7, 2020 2 hours ago, fas42 said: I have spent years playing with optimising audio systems, where a very subtle tweak can cause a dramatic change in the subjective presentation I'm trying to figure out where I have heard this before ??🤔 opus101 1 Sound Minds Mind Sound Link to comment
Popular Post Audiophile Neuroscience Posted March 7, 2020 Popular Post Share Posted March 7, 2020 12 hours ago, cat6man said: I have to disagree with much of the above. 1. i have spent 30+ years simulating complex digital telecommunications systems and, while often causing much consternation among my colleagues over this time (everyone like easy answers), i have found that MOST simulations oversimplify the problem and answer a question or problem, but via oversimplification or by not incorporating something (known or unknown), they do not solve THE question or problem. do you have a realistic jitter spectrum? what is the PDF (probability density function of the jitter)? what is the reconstruction filter? it is technically obvious from the math (don't panic, not included here) that the combination and interaction of the jitter with the reconstruction filter are intimately related, so how is this handled? some filters are not, in fact, even linear as some have lookup tables for filter coefficients that are data sequence dependent. you may use your program to see if your particular waveform and jitter stimulus is/isn't audible to an individual (and there is value in that) but abstracting that to DACs in general is highly questionable. 2. "Jitter is a fairly simple concept"? sorry, but that just isn't correct. jitter has a spectrum, it has a pdf, it may have various forms of correlation, the clock may pick up noise of various sorts which could be random, impulsive, RFI, etc. i will try out your program, assuming it runs under WINE, as i'm curious to see what i can/cannot hear but i know enough about simulations to be suspicious of claiming relevance of a level below which jitter not not matter. let's try a gedanken experiment. assume i have a 50ps rms jitter clock and there is an impulsive noise (power line spike for example......A/C is pretty crappy) impacting that low level signal 1% of the time and causing the clock off instantaneously by 10x the RMS jitter (500ps). i'm guessing the average RMS jitter measurement would not change at all but that the DAC would see a 10x timing offset 410 times a second (i.e. 1% of the time)...........maybe that could be audible? i don't know but it certainly seems possible and something that would likely (?) not be measured with averaging turned on. [technical analogy--feel free to skip] an example i know intimately from simulation: in a 4G LTE system, high speed data is controlled by a 'scheduler' that assigns time slots at the mobile and base station to different users. in addition to assigning time slots to each mobile user, the scheduler must assign from a limited set of control channel slots in order to tell each mobile when its data time slot is coming up. if there are not enough control channel time slots available to serve all the mobile users at a specific time, that mobile user is temporarily blocked and cannot send or receive data. the metric commonly used in simulations was average control channel utilization, and it was thought that keeping that value below 70-80% on average was sufficient for good system operation. however, simulation of many mobile data users with many different data usage profiles showed interesting results. even with say 50% control channel utilization, the blocking could be as high as 5-20% as the distribution of the number of instantanous users could be highly skewed. therefore, the solution turned out to be much more complex than expected as the tail of the distribution of #users needing control channel slots dominated overall performance and the average utilization was essentially irrelevant. just a little non-audio example to show you where i'm coming from. there is always a simple answer to complex problems, but it will often be wrong. unfortunately, many people (and upper management) prefer a simple answer to a complex "well it depends" answer. as always, YMMV IMHO a refreshing way of looking at things. It has been said "to the simple everything appears simple" which is a pejorative way of perhaps explaining why most/many of us just want answers expediently and especially in the neat form of a black and white test result . A better way of expressing it may be " Everything should be made as simple as possible, but not simpler". Bill Brown and Superdad 2 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted March 7, 2020 Share Posted March 7, 2020 I think " Everything should be made as simple as possible, but not simpler" (Einstein? but could be apocryphal) is a great goal but of course there is "reasonably practicable". In either case it is difficult to agree (or know?) when the goal has been reached. happy to continue discussing elsewhere but not here as I think it would move off topic. Cheers David opus101 1 Sound Minds Mind Sound Link to comment
Audiophile Neuroscience Posted March 10, 2020 Share Posted March 10, 2020 On 3/8/2020 at 11:42 AM, Superdad said: Yes, Placebo Domingo is one of my favorite opera singers. He fakes me out every time. Yes, and his evil twin Nocebo Damingo ! Superdad 1 Sound Minds Mind Sound Link to comment
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