Loudness vs.string tension

[LCF]

Here is a photo that Marty posted a while back of his #21 which shows his very clever lightweight way of dealing with afterlength. I post this here so we can think about whether having the afterlength attached via a tailpiece and tailgut to an endblock is crucial.

[Aston4]

5 hours ago, LCF said:

Here is a photo that Marty posted a while back of his #21 which shows his very clever lightweight way of dealing with afterlength. I post this here so we can think about whether having the afterlength attached via a tailpiece and tailgut to an endblock is crucial.

speechless

(regain voice)

I am an afterlength nerd and believe I hear a huge difference.

I do not care what anyone else thinks about afterlength.

Is there a recording of that fiddle?

That fiddle should be in a movie, and in a painting.

I want to play that fiddle.

Is there a recording of that fiddle?

[reguz]

Dear Jezzupe

It was very kind of you to give this answer. It is quite possible that most violin makers have a scattered mind, scattered by the vast amount of literature available. You can probably fill your room from floor to ceiling with descriptions of pretty much everything about violins. For me as a technician, it became interesting to try to find an answer based on particular the belly where the sound is produced. I found a geometry that in a simple way describes and gives answers to how the instrument came to be. At least that's how I look at what I found. Both planimetric and three-dimensional. When you have such an answer, you don't want to keep it a secret. I offer myself and share my knowledge. Despite that, there may be people who are stuck in a way of thinking by old and also new descriptions of how a violin has come to be and works. The most remarkable thing is how people connected to VSA readily swallow the description that an instrument is deformed by string tension.

C Gough, J Woodhouse and J Curtin all say that the center the sound post is pushed down. They have arrived at this by placing the instrument on end blocks and allowing the string tension to deform the instrument. But It’s the end block that moves upwards in relation to the sound post, but since we are dealing with gravitational forces, the instrument remains on its support and now we measure WHAT HAPPENED TO THE SOUND POST. Yes, the center has moved down. Easy to measure the distance to the table. They also show in the picture they sent me that when the belly is flattened it becomes wider at the rib and the sound stick presses on the back plate which retracts the rib.

This is completely incorrect and IMPOSSIBLE. When you continue year after year by thinking and publishing their circumstance. It also turns out that G Stoppani, who produces Mode conditions where the end blocks do not move but the center does. This is impossible and completely wrong. I say poor violin makers to be fed such simple inaccuracies. On my website with documents, everything is explained in a simple way.  www.zuger.se

 Yes, you must have your own interest in wanting to know more and read and understand. If you don't understand, you ask. Enough about this. The violin makers who apply the production of the arching shape based on how I describe get their best results. It was and is my interest to share. Nothing else.

Once again Jezzupe Thank you for your kind words

[David Burgess]

1 hour ago, reguz said:

The most remarkable thing is how people connected to VSA readily swallow the description that an instrument is deformed by string tension.

C Gough, J Woodhouse and J Curtin all say that the center the sound post is pushed down. They have arrived at this by placing the instrument on end blocks and allowing the string tension to deform the instrument. But It’s the end block that moves upwards in relation to the sound post, but since we are dealing with gravitational forces, the instrument remains on its support and now we measure WHAT HAPPENED TO THE SOUND POST. Yes, the center has moved down. Easy to measure the distance to the table. They also show in the picture they sent me that when the belly is flattened it becomes wider at the rib and the sound stick presses on the back plate which retracts the rib.

This is completely incorrect and IMPOSSIBLE.

 What a bunch of BS! 
Have you considered focusing your mechanical physics acumen on something more useful, like amassing a personal fortune playing beer pong?

[jezzupe]

2 hours ago, reguz said:

Dear Jezzupe

It was very kind of you to give this answer. It is quite possible that most violin makers have a scattered mind, scattered by the vast amount of literature available. You can probably fill your room from floor to ceiling with descriptions of pretty much everything about violins. For me as a technician, it became interesting to try to find an answer based on particular the belly where the sound is produced. I found a geometry that in a simple way describes and gives answers to how the instrument came to be. At least that's how I look at what I found. Both planimetric and three-dimensional. When you have such an answer, you don't want to keep it a secret. I offer myself and share my knowledge. Despite that, there may be people who are stuck in a way of thinking by old and also new descriptions of how a violin has come to be and works. The most remarkable thing is how people connected to VSA readily swallow the description that an instrument is deformed by string tension.

C Gough, J Woodhouse and J Curtin all say that the center the sound post is pushed down. They have arrived at this by placing the instrument on end blocks and allowing the string tension to deform the instrument. But It’s the end block that moves upwards in relation to the sound post, but since we are dealing with gravitational forces, the instrument remains on its support and now we measure WHAT HAPPENED TO THE SOUND POST. Yes, the center has moved down. Easy to measure the distance to the table. They also show in the picture they sent me that when the belly is flattened it becomes wider at the rib and the sound stick presses on the back plate which retracts the rib.

This is completely incorrect and IMPOSSIBLE. When you continue year after year by thinking and publishing their circumstance. It also turns out that G Stoppani, who produces Mode conditions where the end blocks do not move but the center does. This is impossible and completely wrong. I say poor violin makers to be fed such simple inaccuracies. On my website with documents, everything is explained in a simple way.  www.zuger.se

 Yes, you must have your own interest in wanting to know more and read and understand. If you don't understand, you ask. Enough about this. The violin makers who apply the production of the arching shape based on how I describe get their best results. It was and is my interest to share. Nothing else.

Once again Jezzupe Thank you for your kind words

"Clutch it like a cornerstone, otherwise it all comes down
Justify denials and grip 'em to the lonesome end
Clutch it like a cornerstone, otherwise it all comes down
Terrified of being wrong, ultimatum prison cell"

[Marty Kasprzyk]

6 hours ago, Aston4 said:

speechless

(regain voice)

I am an afterlength nerd and believe I hear a huge difference.

I do not care what anyone else thinks about afterlength.

Is there a recording of that fiddle?

That fiddle should be in a movie, and in a painting.

I want to play that fiddle.

Is there a recording of that fiddle?

I had posted this 2016 recording by Elias Goldstein playing viola no. 21 before but here it is again https://www.violinist.com/blog/laurie/20166/19565/

Its frequency response curve (FRC) is also attached.  

From this FRC the amplitudes of each harmonic (1 to 25 with number 1 being the fundamental harmonic) of every note in a chromatic scale was found and plotted which is attached. Each note has its own unique harmonic profile and color which makes this viola seem more interesting than if they all had the same profile and were all grey.

One measurement of a note sound's "brightness" is how large the harmonic centroid (balancing point) is.  The note's centroid is the sum of the harmonic numbers times their amplitudes divided by the sum of their amplitudes.  A plot of this is also attached.

From this it can be seen that the low notes of this viola are actually quite bright and the brightness decreases at higher pitches because fewer and fewer upper harmonics are present.  Thus these high notes are quite "dark" and the low notes are quite" bright".  The low notes seem "complex", "rich", "broad" ect. while the upper ones seem "clear" and "pure" etc.

This is usually desireable and it is a result of the amplitude's steep fall-off at high frequencies (~4000Hz) seen in the FRC. It is important to get this fall-off at the right frequency to avoid a "tubby, dull" if it is too low or "strident", "harsh" character if it is too high.

 

 

[LCF]

9 hours ago, Aston4 said:

I am an afterlength nerd and believe I hear a huge difference.

I do not care what anyone else thinks about afterlength.

 

Perhaps because you always have an afterlength attached to a floating tailpiece etc etc you HAVE to be an afterlength plus tailpiece nerd. 

[Aston4]

2 hours ago, Marty Kasprzyk said:

I had posted this 2016 recording by Elias Goldstein playing viola no. 21 before but here it is again https://www.violinist.com/blog/laurie/20166/19565/

Its frequency response curve (FRC) is also attached.  

From this FRC the amplitudes of each harmonic (1 to 25 with number 1 being the fundamental harmonic) of every note in a chromatic scale was found and plotted which is attached. Each note has its own unique harmonic profile and color which makes this viola seem more interesting than if they all had the same profile and were all grey.

One measurement of a note sound's "brightness" is how large the harmonic centroid (balancing point) is.  The note's centroid is the sum of the harmonic numbers times their amplitudes divided by the sum of their amplitudes.  A plot of this is also attached.

From this it can be seen that the low notes of this viola are actually quite bright and the brightness decreases at higher pitches because fewer and fewer upper harmonics are present.  Thus these high notes are quite "dark" and the low notes are quite" bright".  The low notes seem "complex", "rich", "broad" ect. while the upper ones seem "clear" and "pure" etc.

This is usually desireable and it is a result of the amplitude's steep fall-off at high frequencies (~4000Hz) seen in the FRC. It is important to get this fall-off at the right frequency to avoid a "tubby, dull" if it is too low or "strident", "harsh" character if it is too high.

 

 

It sounds beautiful!  The player seemed impressed

 

I understand the second graph.  Fascinating. I'm going to have to come back and stare at the others to figure out what is going on, have to run now...

[LCF]

5 hours ago, reguz said:

Dear Jezzupe

It was very kind of you to give this answer. It is quite possible that most violin makers have a scattered mind, scattered by the vast amount of literature available. You can probably fill your room from floor to ceiling with descriptions of pretty much everything about violins. For me as a technician, it became interesting to try to find an answer based on particular the belly where the sound is produced. I found a geometry that in a simple way describes and gives answers to how the instrument came to be. At least that's how I look at what I found. Both planimetric and three-dimensional. When you have such an answer, you don't want to keep it a secret. I offer myself and share my knowledge. Despite that, there may be people who are stuck in a way of thinking by old and also new descriptions of how a violin has come to be and works. The most remarkable thing is how people connected to VSA readily swallow the description that an instrument is deformed by string tension.

C Gough, J Woodhouse and J Curtin all say that the center the sound post is pushed down. They have arrived at this by placing the instrument on end blocks and allowing the string tension to deform the instrument. But It’s the end block that moves upwards in relation to the sound post, but since we are dealing with gravitational forces, the instrument remains on its support and now we measure WHAT HAPPENED TO THE SOUND POST. Yes, the center has moved down. Easy to measure the distance to the table. They also show in the picture they sent me that when the belly is flattened it becomes wider at the rib and the sound stick presses on the back plate which retracts the rib.

This is completely incorrect and IMPOSSIBLE. When you continue year after year by thinking and publishing their circumstance. It also turns out that G Stoppani, who produces Mode conditions where the end blocks do not move but the center does. This is impossible and completely wrong. I say poor violin makers to be fed such simple inaccuracies. On my website with documents, everything is explained in a simple way.  www.zuger.se

 Yes, you must have your own interest in wanting to know more and read and understand. If you don't understand, you ask. Enough about this. The violin makers who apply the production of the arching shape based on how I describe get their best results. It was and is my interest to share. Nothing else.

Once again Jezzupe Thank you for your kind words

I strongly urge you to share your ideas as widely and enthusiastically as you care to but not here. It is the wrong place to do that. 

[Marty Kasprzyk]

16 hours ago, LCF said:

Marty, how thick are your Pawlonia boards usually, or are you using birch?

The top plate averaged 3.1mm and the back plate averaged 3.3mm.   The Paulownia's density was 0.28g/cc.

The 2016 viola #21 shown in the photo and video had almost all of its wood parts made with Paulownia.  The one piece neck/fingerboard/tail piece had a 1/2 inch dia. carbon fiber tube in its center to give it additional stiffness.

Mahogany was used for the bridge.  The total weight including its chin rest and shoulder rest pads for the back was about 480g.

Later violas used KoskiPly 0.8mm 3ply birch plywood that has a density of 0.52g/cc for the back and ribs.

The most recent two used the 0.8mm plywood for the top instead of the Paulownia wood.

The viola I'm now building has a 0.4mm birch plywood top plate.

 

[Victor Roman]

3 hours ago, Marty Kasprzyk said:

From this it can be seen that the low notes of this viola are actually quite bright and the brightness decreases at higher pitches because fewer and fewer upper harmonics are present.  Thus these high notes are quite "dark" and the low notes are quite" bright".  The low notes seem "complex", "rich", "broad" ect. while the upper ones seem "clear" and "pure" etc.

I am sorry to say but I do not hear the "complexity" you are talking about. And "dark" high notes are a problem in a larger hall. It is probably a usable instrument but the quality of the tone is pretty much "indifferent". Another and a very common issue is that the pitch is not clear. If your intention is to solve some known tonal issues with violas, this experiment doesn't ring promising, to me.

[Marty Kasprzyk]

12 hours ago, Aston4 said:

speechless

(regain voice)

I am an afterlength nerd and believe I hear a huge difference.

I do not care what anyone else thinks about afterlength.

Is there a recording of that fiddle?

That fiddle should be in a movie, and in a painting.

I want to play that fiddle.

Is there a recording of that fiddle?

I've experimented with many different afterlengths.  Some players insist that bowing the afterlengths should produce the exact 6x frequency change from using a 1/6 afterlength/ string length ratio.

But for my real small violas the string afterlength is limited by my one piece neck/fingerboard/tailpiece design.  If it is too long the end of it hits the player's nose which produces a peculiar sound when it vibrates during bowing-- much more nasal than usual.

[LCF]

5 hours ago, Marty Kasprzyk said:

If it is too long the end of it hits the player's nose which produces a peculiar sound when it vibrates during bowing-- much more nasal than usual.

[LCF]

10 hours ago, Marty Kasprzyk said:

The top plate averaged 3.1mm and the back plate averaged 3.3mm.   The Paulownia's density was 0.28g/cc.

The 2016 viola #21 shown in the photo and video had almost all of its wood parts made with Paulownia.  The one piece neck/fingerboard/tail piece had a 1/2 inch dia. carbon fiber tube in its center to give it additional stiffness.

Mahogany was used for the bridge.  The total weight including its chin rest and shoulder rest pads for the back was about 480g.

Later violas used KoskiPly 0.8mm 3ply birch plywood that has a density of 0.52g/cc for the back and ribs.

The most recent two used the 0.8mm plywood for the top instead of the Paulownia wood.

The viola I'm now building has a 0.4mm birch plywood top plate.

 

There is one slide in the Woodhouse seminar where he asks the question

"Do the Schelleng force limits vary between instruments or between notes?"

And his answer is --- "Maximum force doesn't but minimum force does. The bigger the body motion, the higher the minimum bow force."

 

 

That should balance out when you match it with lower tension stringing.  

 

 

[Anders Buen]

10 hours ago, LCF said:

There is one slide in the Woodhouse seminar where he asks the question

"Do the Schelleng force limits vary between instruments or between notes?"

And his answer is --- "Maximum force doesn't but minimum force does. The bigger the body motion, the higher the minimum bow force."

 

 

That should balance out when you match it with lower tension stringing.  

 

 

I think this is correct. We never hear wolves on hardangerfiddles, even if some of them are built very light.

[iNeedAnswers]

On 4/3/2024 at 10:20 AM, reguz said:

[...]

Many such beams together as a bundle respond on specific frequency. That may shift when another produced frequency on the string gives another input under the bridge feet.

[...]

I shortened the quote, but my answer refers to the complete post. 

I am not a violin maker, but I am a theoretical physicist who modells similar stuff for many years now. 

I am sorry to be that harsh, but that is a huge pile of bs bingo. A crude undercomplex model by someone obviously not trained in that field. We could start at the difference between spring like behavior and elasticity, two very different things. You basically try to condense the complexity of 4d into 1d, tensors into linear equations, a dynamic system into a semi static, a complex structured material with inhomogeneous behavior, but not just coupled along some vectors, into beams of homogeneous material along the grain. That doesn't work at all. The lack of your model becomes even more obvious when we look at dynamic bowing and changes in behavior. If we increase and decrease pressure in strings during bowing we get a swelling in sound and pitch shift at the same time. Your model would dampen itself within the shifting pitch, needing to be resaturated in energy for every pitch shift, which is obviously not the case. Your model does not work with any dynamic situation, therefore cannot be right. 

[Aston4]

1 hour ago, iNeedAnswers said:

I shortened the quote, but my answer refers to the complete post. 

I am not a violin maker, but I am a theoretical physicist who modells similar stuff for many years now. 

I am sorry to be that harsh, but that is a huge pile of bs bingo. A crude undercomplex model by someone obviously not trained in that field. We could start at the difference between spring like behavior and elasticity, two very different things. You basically try to condense the complexity of 4d into 1d, tensors into linear equations, a dynamic system into a semi static, a complex structured material with inhomogeneous behavior, but not just coupled along some vectors, into beams of homogeneous material along the grain. That doesn't work at all. The lack of your model becomes even more obvious when we look at dynamic bowing and changes in behavior. If we increase and decrease pressure in strings during bowing we get a swelling in sound and pitch shift at the same time. Your model would dampen itself within the shifting pitch, needing to be resaturated in energy for every herpitch shift, which is obviously not the case. Your model does not work with any dynamic situation, therefore cannot be right. 

Oh!!!!!

Welcome to this terrible thread!

Please, if you enjoy sighing and shaking your head and muttering under your breath:

Could you please go back earlier in this thread and see where I quoted some equations and a paper purporting to model the behavior of strings?  My physics education was undergraduate, simplistic, and now mostly forgotten.

Can you explain what is missing in those models, and whether they can be improved?

Sorry about the terrible posting limitation of this board, I think it goes away after 10 posts.

[LCF]

16 hours ago, Anders Buen said:

I think this is correct. We never hear wolves on hardangerfiddles, even if some of them are built very light.

I have sometimes wondered if the understrings are a complex set of wolf eliminators?

[Marty Kasprzyk]

On 4/5/2024 at 6:14 AM, LCF said:

There is one slide in the Woodhouse seminar where he asks the question

"Do the Schelleng force limits vary between instruments or between notes?"

And his answer is --- "Maximum force doesn't but minimum force does. The bigger the body motion, the higher the minimum bow force."

 

 

That should balance out when you match it with lower tension stringing.  

 

 

 

17 hours ago, Anders Buen said:

I think this is correct. We never hear wolves on hardangerfiddles, even if some of them are built very light.

Jim Woodhouse often recommends using lighter tension strings if wolf notes are a problem.  

His below graph of the minimum bow force for a cello which shows a strong wolf note on the 173 Hz F3 note played on the C string as the top line. The three lines below that show this  peak with lower amplitudes played with the lighter G, D, and A strings. (from his attached wolf note report)

His equations for the minimum bow force include the string impedance Zo squared divided by the body resisistance R.  So even though a hardanger has a light body with a low R,  its lower tension srings with their lower impedance have a greater lowering effect on the minimum bow force which helps in preventing wolf notes.

It appears that Hardanger makers have a good feel for this stuff.

 

wolf notes, Woodhouse .pdf

[Dr. Mark]

4 hours ago, iNeedAnswers said:

I am sorry to be that harsh, but that is a huge pile of bs bingo

3 hours ago, Aston4 said:

Please, if you enjoy sighing and shaking your head and muttering under your breath:

Hi -  Reguz was kind enough to start a new thread Violin Structure and Function for those who would care to discuss his ideas.

[LCF]

10 hours ago, Aston4 said:

Oh!!!!!

Welcome to this terrible thread!

On the contrary I think there are some important contributions in this discourse. You need to learn to filter signal from noise. 

 

Get yourself a copy of the Fletcher and Rossing book "The Physics of Musical Instruments". It's very readable, covers a huge range of stuff and is aimed at undergraduate level understandings. My copy is worn out with the covers falling off and dozens of scribbled bookmarks stuck in the pages. The Arthur Benade book is also essential background reading "Fundamentals of Musical Acoustics", available as a Dover reprint. 

Both are classic texts but who reads books nowadays?

[Aston4]

41 minutes ago, LCF said:

On the contrary I think there are some important contributions in this discourse. You need to learn to filter signal from noise. 

 

Get yourself a copy of the Fletcher and Rossing book "The Physics of Musical Instruments". It's very readable, covers a huge range of stuff and is aimed at undergraduate level understandings. My copy is worn out with the covers falling off and dozens of scribbled bookmarks stuck in the pages. The Arthur Benade book is also essential background reading "Fundamentals of Musical Acoustics", available as a Dover reprint. 

Both are classic texts but who reads books nowadays?

It is very difficult these days to sit down and slog through a text.  I don't claim to have any more of an attention span than anyone else, which last time I checked, is about half that of a goldfish.  

Nevertheless, thank you for the suggestion, those are added to my reading list... $91 

[LCF]

38 minutes ago, Aston4 said:

It is very difficult these days to sit down and slog through a text.  I don't claim to have any more of an attention span than anyone else, which last time I checked, is about half that of a goldfish.  

Nevertheless, thank you for the suggestion, those are added to my reading list... $91 

Less than a packet of strings and will last much longer. 

[Marty Kasprzyk]

15 minutes ago, Aston4 said:

It is very difficult these days to sit down and slog through a text.  I don't claim to have any more of an attention span than anyone else, which last time I checked, is about half that of a goldfish.  

Nevertheless, thank you for the suggestion, those are added to my reading list... $91 

Spending the time reading the Fletcher and Rossing book is far more helpful than wasting the time spent reading stuff here.  

On the other hand it is sleep inducing if that is helpful.

 

 

[LCF]

4 hours ago, Marty Kasprzyk said:

Spending the time reading the Fletcher and Rossing book is far more helpful than wasting the time spent reading stuff here.  

On the other hand it is sleep inducing if that is helpful.

 

 

Marty, some of it is incredibly exciting like when N.F. pulls the woodwind perturbation charts out of the calculus of variations!