Loudness vs.string tension

[LCF]

6 hours ago, Aston4 said:

So it does not answer, well, the question of "Loudness vs. Tesion" in the context of a bowed stringed instrument?

No. It's not one question either.

[iNeedAnswers]

5 hours ago, Dr. Mark said:

Talk is cheap.  Prove it.

 

A prove is something that usually takes a lot of effort, but this is rather easy to make it highly plausible at least.

What you are basically saying in point one is, two different violins are not the same instrument, even with the same setup, and two different setups result in two different results. That is a rather cheap conclusion to be honest and a bit unfair to ask a prove for something as profound as that. Different spruces and shapes have different wave propagation, for example, different bridges are rather easy to show using something like a damper, or the ultra light violin bridge, different sound posts change coupling and preload, just to mention a few things. Energy transfer not being affected by any of that would be highly unplausable. 

Two your second point I refer to the paper mentioned earlier. Different tension means different transport in energy within the string, which is enough to cause a difference in loudness. Of course it also changes preload in the violin and load distribution, which would be rather strange to not effect the system as such as well. 

Really, I thought this is the very basic agreement at which the discussion starts, not the discussion itself.

 

[iNeedAnswers]

On 3/28/2024 at 9:52 AM, David Burgess said:

A higher tensions string, at the same length and pitch, will have more mass. I would expect this to put more energy into the violin.
However, it seems that too much energy going into a violin can overdrive it, making it "choke". Can't be played aggressively. The loudness tops out early, and the sound goes downhill (maybe even reduces in apparent loudness) and fails to maintain normal "slip-stick" action if it's pushed beyond that early peak. This reduces the breadth of the sound palette and loudness available to the player.

(In my experience and opinion)

This is very much my experience as well. This possibility of choking violins by giving it too much, I have also seen something similar happening with powerful bows, makes me think a lot about balance of dampening in violins. It seems to me, that this is a key concept next to making it able to move freely.

I would love to play one of your instruments David, but unfortunately they are hard to get a hand on in the EU.

[ctanzio]

On 4/7/2024 at 8:46 PM, Aston4 said:

I would like to see the math, for anyone who wants to throw some down.

If you are referring to recent posts about tensors, my advice is to find something more useful to do, like stick bamboo shoots under one of your fingernails.

The term tensor can, and frequently is, used to mean anything that mathematically manipulates a set of mathematical objects, like numbers, vectors or even sets of tensors.

It is a mathematical TOOL, which means its usefulness depends very strongly on what you are trying to manipulate and how the various properties you are measuring interact with each other.

In the more precise use of the term, it is a tool of geometry and used to transform one way of looking at something to another way. It lets one explore properties that are independent of how one looks at the system, sometimes called invariances in mathematics, or symmetries in physics.

These geometric uses of tensors are NOT universally applicable to other uses of the term, like the relationships of tension versus loudness of violin strings, which can be very non-linear.

 

[ctanzio]

2 minutes ago, ctanzio said:

 

<fat fingers pressing the wrong button>

[LCF]

1 hour ago, ctanzio said:

If you are referring to recent posts about tensors, my advice is to find something more useful to do, like stick bamboo shoots under one of your fingernails.

The term tensor can, and frequently is, used to mean anything that mathematically manipulates a set of mathematical objects, like numbers, vectors or even sets of tensors.

It is a mathematical TOOL, which means its usefulness depends very strongly on what you are trying to manipulate and how the various properties you are measuring interact with each other.

In the more precise use of the term, it is a tool of geometry and used to transform one way of looking at something to another way. It lets one explore properties that are independent of how one looks at the system, sometimes called invariances in mathematics, or symmetries in physics.

These geometric uses of tensors are NOT universally applicable to other uses of the term, like the relationships of tension versus loudness of violin strings, which can be very non-linear.

 

All of the above. 

[iNeedAnswers]

Right, it is just a tool and nothing else. I really did not want to go into it at all really, but I felt a bit pushed to it. It would be the right tool to describe the model reguz suggested. And yes, it still would be a faulty, but at least consistent to what he initially proposed by him. If you need tensors, learn about them, if not, just ignore their existence. At no point I wanted to suggest they are a tool to solve violins. 
I know of applications where tensor fields are not invariant anymore, for example in Stellarator theory. It kind of defeats its original purpose, but I gets used like this. However, more of a fun fact kind of input than anything else.  

I am actually confident in stating that there is no analytical solution to modeling a violin available. So from my perspective, it is a useless discussion from the get-go. Understand a few basic principles, optimizations through variation, I think this allows better success.

[VicM]

34 minutes ago, iNeedAnswers said:

I am actually confident in stating that there is no analytical solution to modeling a violin available. So from my perspective, it is a useless discussion from the get-go. Understand a few basic principles, optimizations through variation, I think this allows better success.

"""We're blessed. I worried you'll be diving into the intricacies of the integro-differential equation of a real string."""

[iNeedAnswers]

4 minutes ago, VicM said:

"""We're blessed. I worried you'll be diving into the intricacies of the integro-differential equation of a real string."""

Didn't you want to show me what I don't understand? You seem to talk down others a lot in areas where you don't have a lot of ideas about

[LCF]

On 4/8/2024 at 10:14 AM, Aston4 said:

I applaud you for trying to step out of the box.

MK doesn't just step out of the box. He puts the box down in the middle of the stage and calls the bomb squad on it. 

[Dr. Mark]

6 hours ago, iNeedAnswers said:

Really, I thought this is the very basic agreement at which the discussion starts, not the discussion itself.

You may have noticed that much of the recurrent discussion in the Pegbox relates to correlating specific aspects of violin design/construction to specific characteristics of violin tone.  Assertions abound, consistent and verifiable results are rather thin on the ground.  We see plausible assertions that lack supporting evidence, and contradictory evidence is chalked up to lack of skill or experience.  If you're talented and knowledgeable enough to the skip to front of the line, accepting and dismissing practice and theory according to your own notions, then you can control the quality and characteristics of the tone produced by any violin you build and more power to you.

There are some people here who are doing the work of generating proof and evidence - Mr. Noon and Mr. Kasperzyk in particular come to mind but there are others.  I don't think it's unreasonable to ask for evidence to back up assertions and anecdotes.

 

[iNeedAnswers]

While I do agree in general, disagreeing with your points would state that either the violin does not influence the sound or the string does not. Did anyone ever really suggest that? That would be a rather phenomenal statement from my perspective. In more detailed questions, things surely get much much thinner and for most questions you could ask me my answer would probably be either that I don't know it or that I think something is more likely to be one way. 

The original question of this thread is a good example. I would think, generally loudness increases with tension due to the energy transport in the string, then again I am not confident in stating what exactly happens with the violin due to the higher tension and the effect described by David, that a violin can be overpowered and go into a weirdly damped mode, is also something I did experience. I know enough to know that I don't know the answer here. 

I am fully aware that I have a very narrow view on those things and I would not attempt to state anything otherwise.

[Dr. Mark]

45 minutes ago, iNeedAnswers said:

disagreeing with your points would state that either the violin does not influence the sound or the string does not. Did anyone ever really suggest that?

It's useful to state relevant points when consolidating an off-track discussion, wouldn't you agree?  

45 minutes ago, iNeedAnswers said:

The original question of this thread is a good example. I would think, generally loudness increases with tension due to the energy transport in the string, then again I am not confident in stating what exactly happens with the violin due to the higher tension and the effect described by David, that a violin can be overpowered and go into a weirdly damped mode, is also something I did experience. I know enough to know that I don't know the answer here. 

I would hypothesize that tension can correlate with loudness - slack strings after all don't produce much sound while tight strings do and that's pretty much true across the board - and easily verified by experiment that anyone can do in their own home.

However, it's not so clear when comparing strings at high tension.  With the same input (again there are conditions, e.g. the impedance of the instrument is independent of string tension, but what I intended to include under ceteris paribus, which seemed inadvertently to pull someone's chain a bit) the same energy/power/force is transferred to the string.  Wouldn't you think that the transverse displacement of the string may consequently be different between higher and lower tension?  Wouldn't you think that the energy transferred to the corpus of the violin might depend upon this? 

Further, it seems that the impedance of the bridge (and other parts) may limit the power transfer from the strings to the body, allowing energy to build up in the strings but limiting the maximum amount of energy radiated by the violin.  Changing this impedance could change the 'loudness' of the violin.  It seems that proposition should be verifiable, wouldn't you agree?  What if we can get no experimental evidence that that is true?  Does that mean the effect doesn't exist, or that it occurs outside the range we need to be concerned about?  Wouldn't answers and practical means of recognizing and adjusting these effects be interesting? ('Useful' is different.  Give an engineer lots of knobs, dials, and switches and he'll be sure to muck with all of them).  Well, I think I'm done trying to explain.

[iNeedAnswers]

If you call stating the most obvious, two different things being not the same, and when someone agrees to it asking for proof os a way to get a discussion back to track, I don't know what to say to that. 

There seems a lot of dogmatism here, I think more than I care for. It's a shame, there seems to be a ton of knowledge as well.

[Dr. Mark]

5 hours ago, iNeedAnswers said:

There seems a lot of dogmatism here,

It's really all in your head, e.g. you've conflated a reason for the two points I stated with that for a later response  Why on Earth did you do that?   And are you surprised that the absurdity of contradicting a statement may be a measure of the statement's truth?  Well, I don't know where you get some of your interpretations and I'm not being paid to figure it out, so... where was I... oh, that's right:

5 hours ago, Dr. Mark said:

Well, I think I'm done trying to explain.

 

[Marty Kasprzyk]

On 4/9/2024 at 10:26 AM, Dr. Mark said:

>  

I would hypothesize that tension can correlate with loudness - slack strings after all don't produce much sound while tight strings do and that's pretty much true across the board - and easily verified by experiment that anyone can do in their own home.

>

I agree with you that string tension correlates with loudness.

My original post mentioned that my small viola had a string length of 34.2cm and that it sounded noticeably less loud than a larger viola with an estimated string length of 37cm.  Both violas used the same Peter Infeld Pi viola strings and the same two players played both instruments.

If we assume zero tension produces zero dB loudness and that full tension produces 30dB with a C string at the specified 12.3lb tension at a string length of 37mm.  Their ratio loudness/tension is 30/12.3 = 2.44dB/lb

The string tension T ratio is proportional to the length ratio squared so T2=  T1(34.2/37)^2=0.854T1

So with the same tuning frequency my small viola has only 0.854(12.3) or 10.5lb string tension on the C string which is 1.8lb less than the big viola.  So this reduced string tension for my small viola should produce about 4.4dB less loudness than the big one which seems like the difference I had heard.

From all this I conclude beginning players should use short instruments.

[Dr. Mark]

1 hour ago, Marty Kasprzyk said:

So this reduced string tension for my small viola should produce about 4.4dB less loudness than the big one which seems like the difference I had heard.

Nice, but is that tension or the instrument?  There are so many effects to evaluate... but I'd certainly want to remove the human factor altogether and use a calibrated input.

What I like about it is that root causes are less important than reliable correlations with aspects that the players and makers have control over.  The details are for us picky types.

[GoPractice]

3 hours ago, Dr. Mark said:

Nice, but is that tension or the instrument?  There are so many effects to evaluate... but I'd certainly want to remove the human factor altogether and use a calibrated input.

 ( ... )

You are just being mean...

[Victor Roman]

Tighter strings allow one to bow with more pressure.

[Victor Roman]

On 4/9/2024 at 3:43 PM, iNeedAnswers said:

I would think, generally loudness increases with tension

It does not or if it does it is a small effect. I playED both steel and synthetic strings. for over 60 years. I can bow much harder on steel strings and if I don't bow hard enough some steel strings do not quite get going. 

[LCF]

6 minutes ago, Victor Roman said:

It does not or if it does it is a small effect. I playED both steel and synthetic strings. for over 60 years. I can bow much harder on steel strings and if I don't bow hard enough some steel strings do not quite get going. 

This and your previous observation are exactly what the Schelleng bow force diagram predicts. Perhaps Marty can lay his hands on one of these plots and link it here, or a link to Schelleng's paper? Or Jim Woodhouse's presentation about wolfs? The famous diagram plots  minimum bow force and maximum bow force  on the Y axis versus position from the bridge on the other axis. The other piece of information you need is that the maximum bow force varies little from one instrument to another but the more responsive a violin is then the higher is the minimum force required to bow it. You can think if this as getting more 'Wolfey' and I don't mean Mozart.  

 

That is really one of the critical points of this thread. It relates to what Marty is trying to acheive, what David Burgess said back on the first page and so on. 

It also relates in a way to what is being discussed atm on the thread which has drifted along to electric violins.

You have to get the bridge dynamics right so the bow can work properly. That includes string tension and bridge compliance, life, the universe and everything.

[LCF]

Btw for a long time when I was younger my favourite strings were Pirastro Chromstahl but they had to be very well played in. I have dry hands so some of them lasted for years. It was awful when one broke and I had to tame a new one.

[Aston4]

1 hour ago, Victor Roman said:

Tighter strings allow one to bow with more pressure.

Oh! Good point.  Took me forever to get used to plain gut strings, I was so used to slamming on Evas.

[Marty Kasprzyk]

5 hours ago, Dr. Mark said:

Nice, but is that tension or the instrument?  There are so many effects to evaluate... but I'd certainly want to remove the human factor altogether and use a calibrated input.

What I like about it is that root causes are less important than reliable correlations with aspects that the players and makers have control over.  The details are for us picky types.

If you are math fan you can see that I have one equation: My small viola wasn't as loud l as his bigger one, and there's two variables--the effect of my shorter string length( 345mm vs. 370mm), and the effect of my smaller instrument body (~14 2/4  in. vs ~16 3/8 in.).  It can't be determined which of the two is responsible for the decreaed loudness.

It seems like a simple experiment to determine the effect of the shorter string length.  Then the rest of the decreased loudness must be due to the different size viola bodies or their construction.

Bow on an open C  string for an experiment.  This same C note can then be played at shorter fingering lengths if the string tension (by turning the pegs) is reduced. The loudness of these identical pitch C notes played at different string lengths can be measured in dB with Audacity software.  The dB vs. string length equation can then be determined.

Unfortunately I'm looking for a relatively small loudness change (a few dB) due to a string length change and my poor bowing(lack of close control of bow speed, bow force,and bowing point)  and inaccurate fingering gives more dB scatter than the string effect I'm trying measure.

I was able to eliminate the fingering  damping variable by gluing on two shorter string length nuts on a different large viola which reduced the string length from the origninal 382mm string length to the estimated 370mm length of the larger viola mentioned and my shorter one at 345mm. The string length was increased by filing away the temporary nuts. A photo is attached.

C, G, and A notes (I didn't have a long enough D string) were played with with these 3 different string lengths and the results were plotted which is attached.  One of the nine points (the A note at 370mm string length) was an odd ball out of the trends which I believe due to my poor bowing.

So it appears that my small viola's shorter string lenght might be giving a dB or two decrease in loudness.  This was big enough that the players noticed it.

I haven't found short strings with a higher tension so I'll try making the instrument body ighter and hopefully more powerful.

[LCF]

1 hour ago, Marty Kasprzyk said:

... Unfortunately I'm looking for a relatively small loudness change (a few dB) due to a string length change and my poor bowing(lack of close control of bow speed, bow force,and bowing point)  and inaccurate fingering gives more dB scatter than the string effect I'm trying measure.

How about the time honoured wire pluck method to gauge response to a uniform input? An open loop of thin copper magnet wire which is used to pull on a string until the wire breaks. The breaking force is very uniform between trials and you can try different directions too.  Guitar pickup wire ( i tried #42 last week), or something slightly thicker works nicely.

Unfortunately my 16" test viola is out of action atm. I discovered that one of the 25 year old strings decided to spontaneously break overnight. Poor quality merchandise I think. 

Another thing you could try is bolting on a longer neck/fingerboard unit.