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How Good is Our Theory?


Michael_Molnar
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Exactly.

You missed the point of my post: what are the regions that light up when a musician has pleasurable experiences versus less pleasurable ones, and can these be detected robustly when the differences between the experiences gets smaller and smaller (a very, very good violin sound versus a very good violin sound).

And, by the way, fMRI is a pretty crude technique given that the stimuli have to be pretty contrasting to be detected reliably. Also note, the differences that have been reported by various groups who appear to have used similar experimental paradigms to interrogate stimulus-response relationships.

So my conclusion at the moment is that a substantial amount of 'normative' fMRI data need to be collected in the 'judging violin sound' experimental paradigm.

ps - I have some experience in this area.

pps - A key aspect of 'robustness' of data is that the results need to be repeatable over time. (

You're already using vocabulary that reveal your biases and expectations.

The fMRI is not solely a measure of pleasure, or even a response sound alone. It's a convolution mapping.

Suppose you have no idea of neuro-anatomy. How would you go about finding out what area corresponds to which functions?

You design experiments to flesh out the structure. You gather the data, including the players' subjective rankings of instruments, then you interpret fMRI images, and come up with hypotheses. You support your thesis via regression analysis. Just like how every other fMRI experiment is done. This method may have its shortcomings but it sure beats the crappy listening tests with "the double-deaf leading the double-blind" that people have done so far.

Gaser et al (2003), Krings et al. (2000) for example, found lower levels of cortical in the motor areas of the brain for professional musicians vs. non-musicians. Now suppose we theorize that a good instrument requires less effort to play than a bad one. If the motor areas (of each musician, for a large percentage of them) show less activation for the higher ranked instruments, that'd be a confirmation of our claim.

Other data that you might gather include how long it took the musician to put down the instrument, which might be another ranking.

I find it difficult to believe there'd no measurable difference in fMRI between an instrument that a player has to beat into submission vs. one that virtually plays itself, especially as you ask the player to play progressively difficult pieces.

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Carleen Hutchins was originally a teacher in bio sciences, I believe. My experience with former teachers, now engineers or whatever, is that they never really stop their teaching and attitude as if everybody are their young pupils. Simplifications and dogmas seem to be part of it, to be a bit rude in my characterisation.

Having said that, Hutchins was a host and main driver in a musical acustics community for many decades. I have met some of those that participated in some of the meetings, often in her own home. She must have been pretty creative in her approach, and have had many theories through her career. If some of you spend the time listening to the youtube movie about her you willhear that she is not fixed to a particular idea, but do e.g. talk about tuning the assembled violin.

She was after all working with peaople like Bob Spear and most likely Deena Spear who are known for her voicing of instruments, using natural sounds from the body rather than the string as the signal.

Hutchins also made available research through the CAS newsletter, later the CAS Journal, and in books like the musical acoustics books in the Benchmark Papers in Acoustics series as well as the research papers in Violin Acoustics with Arthur Benades wife I believe. Although she is known for her tap tuning ideas (there are more than jut one of these), she became more interested in her violin actet family in her later years. I do not think violins per se was her main interest. She was a viola player, and I would be interested in hearing what comments makers that have come across her violas have to say.

I know a former bass soloist who have tried Hutchins basses, and they were very easy to play and were good instruments.

In many respects she was a different animal, being a female maker and researcher and in being pretty dominant. She was wrong about a few things, e.g. the B1- she attributed to be the A1, and lost a bit focus I guess with time. I never met her, but the dogma around personalities is something we may see from people around the persons in mind. I think we can see bits of this even on this forum. Some great makers and personalities become a bit dogmatic with their age. Nothing special about that.

According to Bob Spear, the tap tuning notes Hutchins recommended came from Jascha Heifetz del Gesu. I have no direct experience with this, but I think an octave relationship between the mode 5 and mode 2 may happen easier in thick plated fiddles with a somewhat flat arching.

I bet we won't se any of us violin acoustics researchers get two articles accepted in the Scientific American as Hutchins did. She had numerous JASA articles as well, not many of us have reached that yet.

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I guess you know Nigel Harris attempts in that direction, as well as Robert Zuger.

Yes, I had seen these, and forgotten about them until I looked them up again.

The Harris papers are full of jargon and hard to follow; Zuger looks like voodoo. Neither one appears to attack the problem of how arching works using fundamental physics and acoustics.

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I would be interested in hearing what comments makers that have come across her violas have to say.

I've seen two of Carleen's violas. One was quite mediocre in both sound and construction. The other, owned by Oliver Rogers, sounded quite good.

I never met Carleen but I did speak to her on the phone a couple of times.

Oliver told me that both he and Carleen were skeptical of the elaborate plate tuning schemes toward the end but that there was so much enthusiasm among the participants that they could not simply change directions. I believe the Oliver stated his qualms in some of his writings.

Oliver stated that he had been looking for an idea such as my 'reciprocity' bi-directional method, that connected modern scientific understanding of acoustics with Renaissance technology and intuition. So that violin acoustics could move from investigating the plates to studying the whole instrument.

Oded

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You're already using vocabulary that reveal your biases and expectations.

?

Point being?

I have to wonder which of us doesn't (perforce) speak from an individual position, including you?

And which of us speaks from the point of view of another?

And which of us possibly speaks without personal bias, expectation or from personal experience?

Aren't these things taken for granted in logical argument? Certainly these things (as in - vocabulary) are not being singled out, as if they were "perjorative"?

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One area of theory that seems to be getting less attention that it should is arching. The only treatment vaguely close (that I'm aware of) is the Woodhouse paper on confined modes of S-shaped steel, which does not appear to have much utility for violinmakers.

I have looked a little at the "ring mode" as described by Evan Davis, just to get some idea where we are on the frequecy-curvature field, and it looks to me like arching would have significant influence on mode shapes (and thus radiativity) even up at the higher frequencies.

The picture is complicated further by the nature of wood, where the properties can vary wildly depending on the angle of the grain to the surface. Some of that variation may contribute to good sound... or not... we don't really know. So advocates of plate bending, in an effort to maximize stiffness in all directions at all times, might not be aiming in the right direction... or might... we don't really know.

There is plenty of concern about total arching, long and crossarch patterns, cycloids, and the like, but not much of the "how" and "why" of the arching from a fundamental physics/acoustics view.

I'll put that on my "to do" list.

I thank you for your exceptionally clear headed approach to applying science to the art of violin making.

I would suggest that since resonances are readily measurable, they have filled the view screen and obscured other lines of observation for most scientifically inclined violin lovers.

Certainly resonance plays a part. But the violin is largely a driven system. Resonances ARE the story for systems that passively respond to an unorganized input, but they are NOT the full story for driven systems, nor for systems that transform and radiate a highly organized input. Indeed, in some driven systems resonances are simply unwanted pests.

I wish more of our scientifically talented people would turn down their attention to the blatantly observable topics of resonance and varnish just a bit and ask: WHAT ELSE MIGHT MATTER??

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< WHAT ELSE MIGHT MATTER?? >

Damping Q.

Hard to measure, probably very important.

The obsession with an excellent violin also makes it hard to consider

simplified models that permit experiments on the basics.

I ran across the 'Cradle of Harmony' violin.

Replace the double curved plates with single curved plates.

Cylindrical.

Reported to be very powerful compared to regular violins.

Of course it is not marketable, even if it works,

but we might learn something.

And the Australian student 'Violin' with flat plates.

What does it sound like. Does it work??

What do we lose with flat plates.

Can we really quantify the difference between

Stainer and Strad??

Is Stainer really sweet and weak?

If several violins from the same maker are very similar

can we say where they are measurably the same and where they differ??

We do not even have a vocabulary (like the wine tasters)

to describe the playing qualities of violins.

We do not even make it clear whether we are talking

Playing or close listening or far listening qualities.

So we sell based on reputation and physical condition and workmanship

to players who judge us on sound and beauty

and talk about optimising our product?

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Yes, I had seen these, and forgotten about them until I looked them up again.

The Harris papers are full of jargon and hard to follow; Zuger looks like voodoo. Neither one appears to attack the problem of how arching works using fundamental physics and acoustics.

They could definitevely have been using simpler explanations. But I guess that is not so easy with a complex surface as violin plates. The curtote cycloids seems like a very simple concept in comparison. But the acoustical or stability benefits from using these does not seem to be straightforward either.

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Gaser et al (2003), Krings et al. (2000) for example, found lower levels of cortical in the motor areas of the brain for professional musicians vs. non-musicians.

It is entirely possible (nay probable - c.f. what happens in the visual cortex within hours of altering ocular input) that the many hours of practice by a musician has led to altered cortical function. I would be interested to see if the cortical activation pattern of a trombonist was similar to that of a violinist, but different to that of a flutist.

In any case, as an objective method for assessing the reaction of a musician to instrument quality, fMRI is still in nappies.

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I find it difficult to believe there'd no measurable difference in fMRI between an instrument that a player has to beat into submission vs. one that virtually plays itself, especially as you ask the player to play progressively difficult pieces.

A touch of bias with no supporting data?

Until there are data otherwise, the 'null' hypothesis stands that there is "no measurable difference in fMRI between an instrument that a player..."

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A touch of bias with no supporting data?

Until there are data otherwise, the 'null' hypothesis stands that there is "no measurable difference in fMRI between an instrument that a player..."

As far as I know, nobody has bothered to do such as study. So the null hypothesis is "we don't know," not that there's no measurable difference.

I'm saying here's how you start getting that data. It may very well lead to a dead end. To say a priori that there can't be any measurable difference is quite frankly BS.

You're welcome to come up and suggest your own experiments that's better than the "double deaf leading the double blind."

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As far as I know, nobody has bothered to do such as study. So the null hypothesis is "we don't know," not that there's no measurable difference.

I'm saying here's how you start getting that data. It may very well lead to a dead end. To say a priori that there can't be any measurable difference is quite frankly BS.

Not BS, but a common scientific method:

http://en.wikipedia.org/wiki/Null_hypothesis

and

http://udel.edu/~mcdonald/stathyptesting.html

etc

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One area of theory that seems to be getting less attention that it should is arching. The only treatment vaguely close (that I'm aware of) is the Woodhouse paper on confined modes of S-shaped steel, which does not appear to have much utility for violinmakers.

I have looked a little at the "ring mode" as described by Evan Davis, just to get some idea where we are on the frequecy-curvature field, and it looks to me like arching would have significant influence on mode shapes (and thus radiativity) even up at the higher frequencies.

The picture is complicated further by the nature of wood, where the properties can vary wildly depending on the angle of the grain to the surface. Some of that variation may contribute to good sound... or not... we don't really know. So advocates of plate bending, in an effort to maximize stiffness in all directions at all times, might not be aiming in the right direction... or might... we don't really know.

There is plenty of concern about total arching, long and crossarch patterns, cycloids, and the like, but not much of the "how" and "why" of the arching from a fundamental physics/acoustics view.

I'll put that on my "to do" list.

Arching is geting a lot of attention lately. A LOT. But this attention is FOR profit and it won't be published or made public anytime soon. New software is available for a couple of years by now which allows direct solutions for thin plates without the horrible aproximations we had to put up before. And of course, new FEA solvers, provided there is sufficient computational power, can match. If the violin would be made out of an isotropic material the problem would be basically solved to a variation of 2-3 percentage points. Models ran with the latest available tools show arching to be the determining factor.

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Arching is geting a lot of attention lately. A LOT. But this attention is FOR profit and it won't be published or made public anytime soon. New software is available for a couple of years by now which allows direct solutions for thin plates without the horrible aproximations we had to put up before. And of course, new FEA solvers, provided there is sufficient computational power, can match. If the violin would be made out of an isotropic material the problem would be basically solved to a variation of 2-3 percentage points. Models ran with the latest available tools show arching to be the determining factor.

VA1?

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You must not have any training in the sciences at all if you have to quote a wikipedia entry.

The null hypothesis doesn't mean the default position is to not perform experiments and gather data. It means you perform the experiments, gather data, and if the results are inconclusive, the null hypothesis must be the default position (i.e. the results did not disprove the null hypothesis).

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I guess you know Nigel Harris attempts in that direction, as well as Robert Zuger. I think arching supresses the vibrations you would get in a flat plate and push the resonances higher in frequency. There may be some interesting going on in understading how the B1+ and B1- modes are affected by the arching, bending versus breathing properties of the plates.

One interesting aspect is plate embossing as used in the automotive industry to supress certain vibration modes using plate shapes. That is metal, but maybe similar effects appear in the violin plates as well?

I think one of the major effects of the arching is dimensional stability and stability against humidity changes. It would have been interesting to see asessments on that in any form.

May I respectfully advise you to pick up a decent book and do some HARD reading ? There are lots and lots of interesting aspects but they simply don't apply to violins. Your 2nd sentence worries me. And so do any refferences to Nigel Harris.

( no offence intended - just friendly advice ! )

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I am a bona fide scientist and read the various theoretical proposals carefully and with great interest. I am also on TOBI-L.

My question is: How much has our various pursuits improved making a superior violin? For example, how has "plate tuning" helped to produce a violin competing with a Stradivari or Del Gesu? Show me one area that truly produces an improved instrument? Are we scientists/engineers just blowing smoke?

I realize that the Luddites will jump on this thread and try to turn this into a field day parade. So, I want my fellow engineers/scientists and experimenters to reply.

Stay tuned.

Mike

The science of history helped the most. Almost everybody knows by now that the best way to make a good violin is to copy a great one ( by Strad or DG ). This is something the french ignored for 200 years...

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May I respectfully advise you to pick up a decent book and do some HARD reading ? There are lots and lots of interesting aspects but they simply don't apply to violins. Your 2nd sentence worries me. And so do any refferences to Nigel Harris.

( no offence intended - just friendly advice ! )

I think you brag to much to be taken seriously, Mr Stross. I have a very firm ground under my comments. Arching stiffens the plates and supresses the vibrations because some of the energy goes into in-plane stretching. Such effects are used in the automotive industry to suppress certain frequency regions or modal problems. The theory is very simple. A plate shape that looks like the vibration will supress it.

Look up Claes Fredös article: http://www.afconsult.com/upload/konsulttjanster/LjudoVibrationer/pdf/SAE_2005-01-2342_Fredo_Hedlund.pdf

What you say about arching can't be true. At the Oberlin Acoustics workshop and other settings, we are blessed with a central specialist from the aviation industry sharing state of the art modeling tool results on the violin. Arching is one of the factors, but not the determining one. Experience talks against you too.

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I won't quote Wikipedia, for fear of being crucified... :unsure:

but a couple of quotes from Poor Richard might be timely:

If you wou’d not be forgotten


As soon as you are dead and rotten, 


Either write things worth reading,


or do things worth the writing.

(1738)

Many a long dispute among Divines may be thus abridg’d,

It is so: It is not so. It is so; It is not so.

(1743)

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You're already using vocabulary that reveal your biases and expectations.

You're welcome to come up and suggest your own experiments that's better than the "double deaf leading the double blind."

Haven't you just now run your own biases up the flagpole, whether you realize it or not?

It's fascinating when someone leaves the restroom, unaware that they are trailing three feet of toilet paper stuck to the bottom of their shoe, who makes fun of someone who forgot to pull their zipper up. :D

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