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Soundpost length experiment


Jim Bress
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Here's an interesting article by Lei Fu, Claudia Fritz, and Gary Scavone on maker, player, and listener perceptions on changes in soundpost length.

Perception of violin soundpost tightness through playing and listening tests, July 2021. The Journal of the Acoustical Society of America 150(1):540. DOI: 10.1121/10.0005587

2021.Perception of violin soundpost tightness through playing and listening tests.pdf

Enjoy,

Jim

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Just now, matesic said:

Anyone? I did find the conclusions moderately revealing, of the near-impossibility (futility?) of performing "science" on the subjective perception of subtle phenomena in which many contributory factors aren't under complete experimental control. 

 

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How qualified is the audience to evaluate the sound?

The audience can't judge playability. The sound may be good, but the instrument may be a hell to play.

It is the player that evaluates and buys the instrument.

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13 minutes ago, MANFIO said:

How qualified is the audience to evaluate the sound?

The audience can't judge playability. The sound may be good, but the instrument may be a hell to play.

It is the player that evaluates and buys the instrument.

That's interesting. I wonder how qualified audience in concert halls is. There are so many contradictions in violin trade...

I read/hear so often how an artist had to work really hard to learn to play a Strad (or other valuable name) but it was worth it because now he projects into the large auditioriums and listeners can enjoy the music. Also often said that strads don't sound good under ear (to player) but good for audience.

There is much more psychlogy than hard physics in evaluating violins...

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22 minutes ago, MANFIO said:

How qualified is the audience to evaluate the sound?

The audience can't judge playability. The sound may be good, but the instrument may be a hell to play.

It is the player that evaluates and buys the instrument.

While participants are anonymous in the article, their qualifications are discussed. 

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Nervous players get their sound post adjusted more often than relaxed players. I think this says all.

Sound post adjustments must make the player feel comfortable with the instrument. No one in the audience will go out of a concert thinking ‘the instrument didn’t sound good!’

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2 hours ago, Nick Allen said:

But who is the arbiter of what sounds good?

As far as viola sound and playability are concerned, I am a good judge. But I can't evaluate a violin or today, I don't have references in my ears for that.

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Another thing is that some players will impose their sound on the instruments. During a viola Congress in Cincinnati, Roberto Dias made all the 40 (or so) violas he played sound about the same. And of course they were all very very different. In the hands of another player, they would sound very differently. 

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While it is nearly impossible to do experiments on a violin involving only a single variable, I think they did a good job of minimizing the variables in a reasonable way, and investigating a subject which has been very controversial, which included feedback from those who played them.

I disagree that they "didn't find anything".

One thing isn't clear to me. Of the six luthiers involved in the playing portion of the test, one is described as not being a player. What sort of feedback was obtained from that luthier, and how?

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24 minutes ago, David Burgess said:

While it is nearly impossible to do experiments on a violin involving only a single variable, I think they did a good job of minimizing the variables in a reasonable way, and investigating a subject which has been very controversial, which included feedback from those who played them.

I disagree that they "didn't find anything".

I agree. The study is undoubtedly well done, and offers some clues on the inherent difficulty (impossibility?) of evaluating this kind of thing. It also seems to me to confirm that the fine setting of the soundpost is more for the player than for the audience.

Furthermore, getting into technical aspects, the adjustable carbon soundpost in my opinion behaves differently than a traditional soundpost, as its ends are movable and allow greater freedom of movement of the plate, while the traditional soundpost has rigid ends, and this could make a difference by itself.

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The adjustable soundpost would be equivalent to installing a  post with rounded ends... except that there would be little damage to the top. ie... it is like thickening the plate and shortening the post... so as David says, a very different behaviour. If, however, the swivel cap on the post could be glued and set once it is in final position,  ... you might get a different result?

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I wonder if the authors asked the luthiers' advice before designing the study, and whether any of the latter (or present company) thought it misconceived and that resources might have been better deployed elsewhere?

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54 minutes ago, Mat Roop said:

The adjustable soundpost would be equivalent to installing a  post with rounded ends... except that there would be little damage to the top. ie... it is like thickening the plate and shortening the post... so as David says, a very different behaviour. If, however, the swivel cap on the post could be glued and set once it is in final position,  ... you might get a different result?

From having played around with one of those soundposts a little bit, I suspect that once it is under load, there is enough friction in the ball joints that the vibration of playing alone won't be enough to move them. But I'm not positive. The inventors would probably be able to answer that.

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I know for sure I have seen this paper and said something about it... but I can't seem to find it now.

Anyway... very detailed and thorough, but I sure wish there was something objective to latch onto, like response curves, to try to get some insight into what is going on physically and acoustically.  Inquiring minds want to know.

When I first saw this paper, I did some investigation on what happens with a longer soundpost.  Essentially all distortion/displacement is in the top, as the back is much more rigid.  And the vertical preload even on a "long" post isn't much compared to the vertical load of the strings.   So a post that's .5mm longer I estimate would see 2 - 3 pounds of vertical force (without the strings) and mostly increase the top arch by .5mm

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I'm convinced that because the violin is such a complex "thing" that instead of these experiments bringing "anyone" closer to understanding, that the more you break down and study/examine individual aspects of the violin the more complex it reveals itself to be, and instead of being closer to understanding, it just creates a new set of questions and unknowns which actually push understanding further away by creating more things we don't know that we didn't know we didn't know. 

and so like a strange paradox, the more you look the less you know

I feel one is much more likely to get some grasp of things when they concede defeat,. and that somethings are best left unknown and to understand that the realm of the violin is that of the unknown, that which is physical, yet purely an object that functions in the realm of "feelings" and so trying to figure it out scientifically is much like sending in a brain surgeon to try to figure out why you are so sad.

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30 minutes ago, Shunyata said:

What you are describing is shibumi - the simple perfection of the whole that cannot be found in its parts.

um, you forgot to say "grasshopper" after describing,:) I'll have to remember that one and add it to my my "are those astronaut pants your wearing?" trove of cheesy pick up lines, with a little reworking we can turn that into gold.:lol:

I would say on a serious note, that I do not think humans are advanced enough at this moment in time to try to seriously undertake understanding the violin completely from a scientific point of view, that will allow for x,y,z recipes for tonal success, and so I think we should drop this ruse and stop pretending like we're advancing anything by doing these tests, focus on production {we know we can make them} and then someday when quantum computing has been perfected, assuming singularity has not killed us off, then we can start getting some answers that hopefully we will be evolved enough to understand.

I feel 500 years from now many of the "relics" from the past will be gone, yet somehow I feel the violin will transcend time, and be one of the few ancient inventions that will be used on a regular basis 500 years from now and that perhaps then we may have earned the right to know.

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1 hour ago, Don Noon said:

I know for sure I have seen this paper and said something about it... but I can't seem to find it now.

Anyway... very detailed and thorough, but I sure wish there was something objective to latch onto, like response curves, to try to get some insight into what is going on physically and acoustically.  Inquiring minds want to know.

When I first saw this paper, I did some investigation on what happens with a longer soundpost.  Essentially all distortion/displacement is in the top, as the back is much more rigid.  And the vertical preload even on a "long" post isn't much compared to the vertical load of the strings.   So a post that's .5mm longer I estimate would see 2 - 3 pounds of vertical force (without the strings) and mostly increase the top arch by .5mm

But over long periods of time, doesn't the back distort also? So, maybe long posts have a slow motion effect on the sound and some (decades or centuries long?) longitudinal study would be needed to measure the changes?? The same long length sound post would initially push and distort the top and then, over time, would the top relax as the back starts to distort. 

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2 hours ago, jezzupe said:

and so like a strange paradox, the more you look the less you know

I think it's more like:  the more you look, the more you realize how much you don't know.  But now you know more than you did before.

55 minutes ago, Dr. Ludwig said:

But over long periods of time, doesn't the back distort also? So, maybe long posts have a slow motion effect on the sound and some (decades or centuries long?) longitudinal study would be needed to measure the changes?? The same long length sound post would initially push and distort the top and then, over time, would the top relax as the back starts to distort. 

Even instantaneously, when you put on the strings, the top will be pushed down and the back will be pushed out.  Using some recent violin deflection measurements,  if you make the post with .35mm preload, the top would bulge out intially (a bit under .35m, while the back would get pushed out just a little bit).   When strings are tightened up, the back would be pushed out .35mm, and the top would then be in its original shape.  Then over time you'd likely see creep as everything sinks further.

These are just some approximate examples, and I have no idea what any of it means tonally.  It may be just coincidence that .35mm appears to be about the average of the preferred post preloads in the paper... or it may be that minimal distortion of the top is preferred.

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