FREQUENCY RESPONSE: EN ENTICING MARKETING STORY
! Warning! - - - long post!!! - - -
@Kvalsvoll, it’s not as if I am unfamiliar with the history or philosophy (for example epistemology) of science. You wrote:
«In science there is one correct answer, and then all the other answers are simply wrong. And the decision on what is correct and what is wrong is based in scientifical technical evidence, and the decision process in itself is based on logic. So there is no middle way».
What you describe here is actucally a binary system, with only two outcomes, one or zero, absolutely correct or absolutely wrong. Limited numbers of states can be described by pure mathematics. If all properties can be fully predicted by pure logic alone, we don’t need experiments to confirm our beliefs or wisdom. I believe
@Cosmik is in the camp of pure mathematics, a camp which I would call “philosophical” not “scientific”.
Reproduction of sound is HIGHLY complex as it is a result of factors such as:
(1) The sound field coming from loudspeaker can be formulated by complex functions, and
(2) Our perception of sound follows a series of complex cognitive processes.
In other words, the prediction of reproduced sound – which means combining (1) and (2) above – is so complex one could liken it to opening a can of worms. However, smart people dealing with complexity have had a recipe for ages: Vox populi. In 1907, Francis Galton, who according to Wikipedia was a “an English Victorian era statistician, polymath, sociologist, psychologist, anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, and psychometrician”, had to revisit his estimations of the wisdom of the public. At the annual show of the West of England Fat Stock and Poultry Exhibition people had a chance to guess the weight of an ox. The most correct estimates won prizes. Surprised by the outcome of the public’s guesses, Galton wrote:
“It appears, then, that in this particular instance, that the vox populi is correct to within 1 percent of the real value (…) The result is, I think, more creditable to the trustworthiness of a democratic judgment than might have been expected”.
Source:
http://galton.org/essays/1900-1911/galton-1907-vox-populi.pdf
The polling method was later refined by none other than the Project RAND to find fast solutions to complex problems utilizing the power of group judgment, by gathering a group of experts (see:
https://en.m.wikipedia.org/wiki/Delphi_method). Needless to say, RAND was populated by the best science people, with the aim of winning the (cold) war. In other words, they didn’t search for a solution as if the outcome were a binary, philosophical one, but a forecasting solution that was adaptive, robust and able to deal with complexity.
So it is in this tradition, the democratic vox populi line of thinking, that audio researchers use polls too instead of mathematics alone to find solutions to the sound reproduction problem, given the fact that predicting both (1) and (2) above is complex when (1) is isolated from (2) and highly complex when (1) and (2) are merged together into one process or experience.
Vox populi and the Delphi method cannot be formulated using mathematics. The outcome may a binary one (“yes” or “no”), but the process leading to “correct” or “incorrect” is not one that can be described by an algorithm. Even the makers of “The Matrix” had to change the formula to yield a better outcome, and the formula needed tweaking all the time!
Because we have entered a scientific process that can be described as vox populi, the wisdom of crowds, we realize the critique against the outcomes – often called “the science” – can be summed up by the usual factors that argue against the polling method. I have for about two decades now worked on vox populi related issues in very big data sets. It gives me some familiarity with the discussion of scientific method, even if my field is not audio related.
My user name is svart-hvitt which means black-white in Norwegian. I chose this user name because of my fascination with science that takes the form of correct-incorrect, like a binary one-zero process. At the same time being in the know that the binary one-zero utcome is a drifting one. I also took the name because I am intrigued by the fact that our utilization of digital ones and zeros are able to represent reality in a convincing manner, while at the same time knowing that “this is not a pipe, it’s a picture of a pipe” (see my avatar).
Science is about getting it about right when we try and describe the world, as Isaac Asmivov brilliantly explained in the essay “The Relativity of Wrong”. He wrote:
“In short, my English Lit friend, living in a mental world of absolute rights and wrongs, may be imagining that because all theories are wrong, the earth may be thought spherical now, but cubical next century, and a hollow icosahedron the next, and a doughnut shape the one after.
What actually happens is that once scientists get hold of a good concept they gradually refine and extend it with greater and greater subtlety as their instruments of measurement improve. Theories are not so much wrong as incomplete”.
Source:
https://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm
I urge every ASR member to read the full story as it goes to the core of the scientific process., dealing with the naïve protests by a young student.
Asimov’s use of the word “incomplete” is critical here. When pointing out that ASR’s go to source of audio science may be incomplete, while also being potentially subject to biases (like position related sound fields, i.e. factor (1) above, funding etc.), it’s as if hell breaks loose.
Previously,
@oivavoi wrote:
“But take the issue of the dipole speaker, for example. In Harman studies, no good. In one of Søren Bech's studies, however, the dipole received the highest rating given a particular placement, and the worst rating, given a different placement”.
Source:
https://www.audiosciencereview.com/...s-and-smooth-off-axis.8090/page-4#post-199430
Instead of unleashing an interesting discussion of Harman’s vox populi process,
@oivavoi was forced to take a defensive position, as if one needs to apologize for bringing up critique of Harman’s methods and research results. The paper that
@oivavoi quoted didn’t come into the discussion, even if if contains much of interest to this debate.
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Take a look at the excerpt from the article (Evans et al., 2009) above. The table shows at least one obvious weakness of the Harman research; the vox populi process was carried out from one loudspeaker position only. The researchers wrote:
“It is evident that the dependence of listeners’ fidelity ratings on position (and room) is also important. Whilst the dipole is rated as worst in Position 2 (less than 1m from the back wall, central), it is rated as best when moved to Position 1 (over 1m from back and side wall). This suggests that the perceived influence of directivity is de- pendent on both position and room type (…) It is also clear that investigations have been limited based upon the nature of the testing arrangement. The use of ‘clinical’ test environments is arguably not representative of true listening scenarios, and whilst the measured reverberation time may be similar to a domestic listening space, the nature of reflections in many standardised listening rooms are not. Also, the majority of tests are conducted with the listener remaining in a fixed ’sweet-spot’ position. If directivity is to be investigated fully, then listening at more than one position should be included, in order to exploit the characteristic traits of each radiation type — one type of directivity may pro- mote well-balanced timbral and spatial listening across a room, however this would be overlooked with traditional testing methods”.
Source:
https://www.researchgate.net/public..._sound_quality_-_a_review_of_existing_studies
The table also shows that research is as much about getting an overview of different voices instead of seeking a favorite voice. That’s why research articles formally contain a part dedicated to literature overview. Meta research articles follow in the same path, where the entire article is devoted to existing research to make a sum-of-the-evidence judgment.
The concept of neutral reproduction of sound has been us for ages. People have searched for colour free sound for over 100 years and Harman have shown that vox populi on average prefers neutral to coloured. However, to reduce factors (1) and (2) above to “frequency response, frequency response and frequency response” is incomplete. It may work as an enticing marketing story if your goal is to push boxes at the highest rate possible, but from a scientific point there is more to factors (1) and (2) above than frequency response.
On the matter of directivity, taken from the Evans et al. (2009) article that
@oivavoi quoted previously, the authors concluded thusly:
“An extensive review of studies and opinions regarding the listener response to loudspeaker directivity has been presented, and it is evident that no detailed conclusions with regard to this matter have been established. Whilst some of the literature indicates small preferential trends, most provides little insight and this can be attributed to the limited nature of the tests carried out. The authors propose to conduct a range of more specific tests which will consider the key research questions that have resulted from other studies, namely the isolation of the directivity feature alone, its influence on different auditory attributes and the nature of listening tests conducted”.
Please note that one of the authors of that article, Søren Bech, was one of the co-authors of the 2017 JAES article I brought up earlier, where the authors wrote:
“Loudspeaker specifications have traditionally described the physical properties and characteristics of loudspeakers: frequency response, dimensions and volume of the cabinet, diameter of drivers, impedance, total harmonic distortion, sensitivity, etc. Few of these directly describe the sound reproduction and none directly describe perception of the reproduction, i.e., takes into account that the human auditory system is highly non-linear in terms of spectral-, temporal-, and sound level processing (see, e.g., [3]). This disconnect between specifications and perception have made it challenging for acousticians and engineers (and consumers) to predict how a loudspeaker will sound on the basis of these specifications”.
Source:
http://www.aes.org/e-lib/browse.cfm?elib=18729
Bech is professor of audio perception at Aalborg University, director of research for Bang & Olufsen and a member of government expert groups (
https://www.linkedin.com/in/s%F8ren-bech-8882aa4/). So Bech is hardly a person who would fall victim of audiophoolery, which I have been accused of when I quoted from his research.
Science is a more complex than a binary process of mathematical properties, a solution waiting for a philosophical answer. “Frequency response, frequency response and frequency response” is an enticing solution to the sound reproduction problem; as enticing as it is incomplete.
This explains too, why I have chosen flat and smooth speakers of excellent vertical and horizontal directivity properties, but still have questions that go beyond the incomplete frequency response answer.