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Evidence-based Speaker Designs

Cosmik

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...there still exist many who assert that a non-disemploying minimum wage is impossible or highly unlikely on a pure theory basis. Meanwhile, the people who have actually empirically studied the impacts of minimum wages on employment have advanced the theory in new ways to explain the actual results they observe, as science is supposed to.
Science, yes. But is science the be all and end all? And these studies are hardly blind are they? If the scientist wants it to be true that minimum wage is 'non-disemploying' then that is what they'll find :).

Should government policy be driven by these 'scientific' observations? I believe that Michael Gove's famous "Britons have had enough of experts..." was referring to the responsibility for political decisions being conveniently offloaded onto such people (having picked the right 'expert' of course).

I am persuaded by Nassim Taleb when he says that a taxi driver is a true expert in his trade, but there is no such thing as a truly expert economist because they are dabbling in something that cannot be learned on a course or improved by practice. And I think common sense suggests that it is *way* beyond understanding by low level empirical observation.
 
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Cosmik

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Well, this conversation sure is moving quickly away from speaker designs into vague circular arguments. :p
It's the designing to "evidence" aspect that is circular. I am attempting to break out of the circle :)
 

Mad_Economist

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This all is off-topic, and I'd happily support a mod purging any mention of econ from this thread. However, while it's here, I'm not keen to let my field's name be dragged through the mud to tar empiricism.

Science, yes. But is science the be all and end all? And these studies are hardly blind are they? If the scientist wants it to be true that minimum wage is 'non-disemploying' then that is what they'll find :).

This sort of banal, handwaving skepticism is sadly a commonality in the discussion of economics. Happily it is wrong, at least for the most part. Although a meaningful influence of authorial bias does exist - see also, the continued employment of David Neumark - the premise that it dominates the output of this field (or any other field of science) is difficult to reconcile with the reversals of consensus which new empirical work have produced.

At one point, a minority of economists argued in favour of minimum wages even as a net gain for low-skilled workers - now it would be controversial to assert that a "moderate" minimum wage would even be disemploying, let alone a net decrease in welfare for low-skilled workers. How do we get from point A to point B on this? The continual refinement of our understanding and theory via empirical work.

Should government policy be driven by these 'scientific' observations? I believe that Michael Gove's famous "Britons have had enough of experts..." was referring to the responsibility for political decisions being conveniently offloaded onto such people (having picked the right 'expert' of course).

I suppose if you assume that there is an "expert" for any preferred policy agenda and that there is no insight to be gained from the sciences, then you might question the purpose of scientific guidance of policy. This is at odds with the consensus that exists within economics on many salient points for policy crafting and implementation, however - while normative goals (and thus optimal policy) vary considerably, the actual outcomes and operation of policy are much less in contention among real experts, and well that it is, otherwise not only could we not agree on what we should do, we'd disagree on what we were doing, had done, and could do. Certainly, it often plays to the advantage of a politician to imply an ambiguity among the experts on a topic - most often if their proposed solution isn't even ideal for their espoused ends - but this doesn't create a real ambiguity within the field.

Perhaps Britons have also had enough of experts on the origins and impacts of climatic change, should we divorce policy from 'scientific observations' on those subjects as well?

I am persuaded by Nassim Taleb when he says that a taxi driver is a true expert in his trade, but there is no such thing as a truly expert economist because they are dabbling in something that cannot be learned on a course or improved by practice. And I think common sense suggests that it is *way* beyond understanding by low level empirical observation.

Taleb's apparent passion since his commercial success has been pontificating pseudophilosophically on Twitter, so I'm not surprised he said that. He particularly seems to have some sort of bone to pick with economics - it might help if he took some time to look into the field he's criticizing. But I suppose the purpose is the opportunity to sound profound and insightful, and that's not limited by the facts.

Well, this conversation sure is moving quickly away from speaker designs into vague circular arguments. :p

From what I have seen of his posting, this appears to be Cosmik's primary purpose in posting on this forum.
 

Mad_Economist

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Putting the on-topic material in a separate comment in hopes of furthering a purge of off-topic - although this diversion could, itself, be argued to be away from topic...

It's the designing to "evidence" aspect that is circular. I am attempting to break out of the circle :)

An approach based on evidence and empiricism may seem circular because it often ends up at a beginning, but do not be fooled, you cannot step into the same river twice. On the way around, the evidence allows us to be rid of past misconceptions and ambiguity, if not completely. Done enough times with sufficient thoroughness, we get a reasonable approximation of the truth, even though each step along the way - and perhaps even each time around - we didn't do optimally. And in science as in amplifiers, negative feedback is a good system :p

What's strange to me is the concept that we can somehow do without - how do we get to the starting point for these grand voyages of concept or idea that pierce the veil of ignorance? Surely we must have had some concept of how things work to formulate our ideas, or is the whole of acoustics a thought experiment?
 

Cosmik

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This sort of banal, handwaving skepticism is sadly a commonality in the discussion of economics.
I wonder why!
...the premise that it dominates the output of this field (or any other field of science) is difficult to reconcile with the reversals of consensus which new empirical work have produced.
... which would also be perfectly consistent with a field that doesn't really have any traction on reality. But it's a circularity (that word again). If economists say they understand the world, and that they are the only ones qualified to judge whether they do - as we see here - then they have it pretty much sewn up! :)

From what I have seen of his posting, this appears to be Cosmik's primary purpose in posting on this forum.
You betray your lack of debating 'chops' when you go personal like that. And that reference to Taleb's "commercial success" is also a bit of a giveaway.
 

Mad_Economist

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... which would also be perfectly consistent with a field that doesn't really have any traction on reality. But it's a circularity (that word again). If economists say they understand the world, and that they are the only ones qualified to judge whether they do - as we see here - then they have it pretty much sewn up! :)

Ah, you're one of those sorts of people. I could dredge up the tired book of achievements here - I personally think that the stabilization of inflation rates under central banks governed by contemporary macro is among the most conclusive answers to whether econ has "traction with reality" - but I doubt you will be convinced, and I doubt that anyone will put stock in your statements on this subject after brushing off a field of science as out of touch with reality, so I no longer have reason to care.

You betray your lack of debating 'chops' when you go personal like that. And that reference to Taleb's "commercial success" is also a bit of a giveaway.

I don't come to this forum to practice my debating chops, I come here to read and participate in productive discussion - a consistent theme of your appearances here has been disrupting that, and I see no reason to sugar coat that. I honestly don't understand why you do it, but I feel it would improve this forum for most involved if you stopped.
 
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svart-hvitt

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Ah, you're one of those sorts of people. I could dredge up the tired book of achievements here - I personally think that the stabilization of inflation rates under central banks governed by contemporary macro is among the most conclusive answers to whether econ has "traction with reality" - but I doubt you will be convinced, and I doubt that anyone will put stock in your statements on this subject, so I no longer have reason to care.



I don't come to this forum to practice my debating chops, I come here to read and participate in productive discussion - a consistent theme of your appearances here has been disrupting that, and I see no reason to sugar coat that. I honestly don't understand why you do it, but I feel it would improve this forum for most involved if you stopped.

Any advanced scholar of ambition needs to pass a PhD. It’s often forgotten that this title is the same irrespective of field of study. Look up what the three letters stand for. A certain philosophical aptitude is necessary if science is to be carried out at the higher levels. One needs to understand, «why do we do this, why do we think the way we do».

@Cosmik practices what’s always been an inherent part of any scientific field.
 

Mad_Economist

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Any advanced scholar of ambition needs to pass a PhD. It’s often forgotten that this title is the same irrespective of field of study. Look up what the three letters stand for. A certain philosophical aptitude is necessary if science is to be carried out at the higher levels. One needs to understand, «why do we do this, why do we think the way we do».

@Cosmik practices what’s always been an inherent part of any scientific field.

Philosophy is not a subject I'm averse to, but musing is not profundity, nor is mysticism. There are fundamental questions to be asked in every field about the assumptions and concepts that field is built upon - this isn't questioned by anyone I know. Attempting to drag every discussion within that field into a vague criticism or navel-gazing about those assumptions and concepts, however, is corrosive to productive dialogue. You have to ask questions to be a philosopher, but constantly asking questions does not make you philosophical.

Edit: I really shouldn't be furthering the derailing of this thread with my grievances, so I'm going to stop here. My apologies to the moderators for dragging this further from the topic.
 

svart-hvitt

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Philosophy is not a subject I'm averse to, but musing is not profundity, nor is mysticism. There are fundamental questions to be asked in every field about the assumptions and concepts that field is built upon - this isn't questioned by anyone I know. Attempting to drag every discussion within that field into a vague criticism or navel-gazing about those assumptions and concepts, however, is corrosive to productive dialogue. You have to ask questions to be a philosopher, but constantly asking questions does not make you philosophical.

Edit: I really shouldn't be furthering the derailing of this thread with my grievances, so I'm going to stop here. My apologies to the moderators for dragging this further from the topic.

I think @Cosmik ’s remark that idea based design triumphs «evidence based design» is a thoughtful one even if I am more in the middle between the two. A powerful idea is worth so much more than improving a faulty idea.

Some speaker designers are bolder and go on new paths instead of improving the old box. Here’s one interesting critique of the legacy speaker by a guy (an AES Fellow) who practices what @Cosmik says.

https://www.thebroadcastbridge.com/...echnology-part-15-a-catalogue-of-shortcomings
 

Mad_Economist

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I think @Cosmik ’s remark that idea based design triumphs «evidence based design» is a thoughtful one even if I am more in the middle between the two. A powerful idea is worth so much more than improving a faulty idea.

I fundamentally disagree that Cosmik has even proposed a meaningful distinction on this front - a "powerful idea" must spring forth from an awareness of the facts which is grounded in the evidence; all new designs submitted to empirical analysis must spring from ideas, these aren't anything but two steps in a process - but unless this thread is retitled to Epistemology of Audio I'll return to topic.

Some speaker designers are bolder and go on new paths instead of improving the old box. Here’s one interesting critique of the legacy speaker by a guy (an AES Fellow) who practices what @Cosmik says.

https://www.thebroadcastbridge.com/...echnology-part-15-a-catalogue-of-shortcomings

I'm familiar with that article, it's perhaps a bit broad, but nonetheless a reasonable indictment of the average speaker - with the exception of the bass reflex comment, at least :p

I imagine you're familiar with Linkwitz's (RIP) even more adventurous criticisms of the conventional approach, if you're a fan of that sort of thing? He went quite far in his statements relative to the support of the literature often as not, but I feel that he contributed a fair bit of reasonable doubt to the conventional approaches.
 

MattHooper

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I think @Cosmik ’s remark that idea based design triumphs «evidence based design» is a thoughtful one even if I am more in the middle between the two. A powerful idea is worth so much more than improving a faulty idea.

Some speaker designers are bolder and go on new paths instead of improving the old box. Here’s one interesting critique of the legacy speaker by a guy (an AES Fellow) who practices what @Cosmik says.

https://www.thebroadcastbridge.com/...echnology-part-15-a-catalogue-of-shortcomings

From that article:

From a stereophonic imaging standpoint, the square loudspeaker enclosure (1) also lets us down, because the acoustic impedance change at the sharp corners causes sound from the tweeter to be re-radiated. The re-radiation interferes with the direct sound to make the directivity pattern periodic. From an imaging standpoint, the sound source is the width of the speaker instead of a point. This aperture effect destroys the imaging ability as no virtual sound source can be narrower than a speaker.

Could this explain why some of us percieve wide bodied/big driver speakers produce wider/bigger/fuller sonic images?
 

Juhazi

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I don't think that the statement above is true. How about in-wall speakers, they work and image well. Diffractions from edges can and should be minimised with appropriate width and rounding.

I have made a spherical mt coax Ang it measures smooth and images well. Bass needs a bigger enclosure. I copied Gradient 1.4 - Google that!
 

Cosmik

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From that article:

From a stereophonic imaging standpoint, the square loudspeaker enclosure (1) also lets us down, because the acoustic impedance change at the sharp corners causes sound from the tweeter to be re-radiated. The re-radiation interferes with the direct sound to make the directivity pattern periodic. From an imaging standpoint, the sound source is the width of the speaker instead of a point. This aperture effect destroys the imaging ability as no virtual sound source can be narrower than a speaker.

Could this explain why some of us percieve wide bodied/big driver speakers produce wider/bigger/fuller sonic images?
I have an open (i.e. ignorant) mind on diffraction. I probably agree with Mr. Linkwitz's observation that:
While I try to minimize visible diffraction ripples in the frequency response for good measure, I have no evidence that even strong diffraction effects have significant audible consequences...
If the effect is a delay (i.e. a very specific phase/frequency/time domain envelope relationship) then the brain may simply compensate for it even if it looks horrendous on a frequency response curve (there are evolutionary reasons why it would be useful to be able to eliminate such confusion from identifying the source of a sound..?).

The purest Blumlein-type stereo from speakers relies on level differences creating 'fake' time differences at the ears, so it also seems possible to me that the diffraction effect is secondary in this mechanism. And even if the stereo is the 'less pure' (non-Blumlein) time-of-arrival variety, symmetry of the speakers and listener may still make it a secondary effect.

As Mr. Linkwitz says, if possible I would always try to minimise it with copious rounding à la Grimm LS1, anyway.
 

Ron Texas

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What is the objective?
 
OP
Ilkless

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I fundamentally disagree that Cosmik has even proposed a meaningful distinction on this front - a "powerful idea" must spring forth from an awareness of the facts which is grounded in the evidence; all new designs submitted to empirical analysis must spring from ideas, these aren't anything but two steps in a process - but unless this thread is retitled to Epistemology of Audio I'll return to topic.



I'm familiar with that article, it's perhaps a bit broad, but nonetheless a reasonable indictment of the average speaker - with the exception of the bass reflex comment, at least :p

I imagine you're familiar with Linkwitz's (RIP) even more adventurous criticisms of the conventional approach, if you're a fan of that sort of thing? He went quite far in his statements relative to the support of the literature often as not, but I feel that he contributed a fair bit of reasonable doubt to the conventional approaches.

This will be my final comment on this topic. I agree that the user you refer to is assuming "ideas" pertaining to acoustic transduction are sui generis. For someone that seems very ready to question fundamental assumptions, it is peculiar to not see any positive argument for this premise to disregard empirical fact underpinning this entire discipline.

The normative goals ("optimal policy") may be up to debate (but unlikely to be wholly arbitrary, since smooth DI transition is supported by psychoacoustic fact in the precedence effect, even if questions of DI magnitude and direct-to-reflected sound ratio vs frequency are not settled).

The acoustical physics are uncontroversial. The original question that spiralled out of control was of baffle step. The user went so far as to question the validity of power response, when it is a direct representation of the actual, physical acoustic radiation of a loudspeaker system - with baffle-step being a natural off-shoot of the wave equation. Cosmik has not managed to falsify the wave equation. This is his burden of proof for his proposition that our current understanding of acoustics - and speaker design based on it - is merely another sui generis idea to be reckoned equally with other abstract conjectures absent direct experimental verification.

edit: To keep this thread on topic, I have updated the HEDD entry in OP and placed it on the main list.
 
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Cosmik

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This will be my final comment on this topic. I agree that the user you refer to is assuming "ideas" pertaining to acoustic transduction are sui generis. For someone that seems very ready to question fundamental assumptions, it is peculiar to not see any positive argument for this premise to disregard empirical fact underpinning this entire discipline.

The normative goals ("optimal policy") may be up to debate (but unlikely to be wholly arbitrary, since smooth DI transition is supported by psychoacoustic fact in the precedence effect, even if questions of DI magnitude and direct-to-reflected sound ratio vs frequency are not settled).

The acoustical physics are uncontroversial. The original question that spiralled out of control was of baffle step. The user went so far as to question the validity of power response, when it is a direct representation of the actual, physical acoustic radiation of a loudspeaker system - with baffle-step being a natural off-shoot of the wave equation. Cosmik has not managed to falsify the wave equation. This is his burden of proof for his proposition that our current understanding of acoustics - and speaker design based on it - is merely another sui generis idea to be reckoned equally with other abstract conjectures absent direct experimental verification.

edit: To keep this thread on topic, I have updated the HEDD entry in OP and placed it on the main list.
I'm not trying to falsify anything except the notion that it is possible to base the design of a transducer on evidence alone.

If the only evidence available is obtained from existing de rigueur narrow-baffle speakers, an entire measurements regime may be built up around it; an entire industry of 'target curves', 'room correction'; expectations of what 'hi-fi' should sound like. And in this situation, designers would be 'missing a trick' that they might be aware of if they used "ideology" rather than basing their designs on evidence alone.

And what constitutes evidence? For many people it seems to be in-room frequency response curves that conflate EQ, the room and the speakers' own dispersion anomalies, not the 'Spin-o-rama' measurements (or even better, software acoustic simulations) that would reveal the speaker's true nature. And even if they had the Spin-o-rama measurements, they would be bewildered by what to do with them. What use are they if the in-room 'target curve' is the aim anyway? Why do you need anything more if human hearing is simply a sliding frequency response window?

Two speakers designed merely to produce the same sparse "evidence" based on an over-simplification of human hearing could sound substantially different to each other (and both rubbish), while two speakers designed to meet some pre-defined theoretical criteria of what the ideal speaker should do would be better and more predictable.
 

Ron Texas

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Idea based speaker design is about the same as marketing based speaker design. An idea is a hypothesis. If supported by insurmountable evidence it becomes a theory and if completely provable, a law of science.
 
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