Loudness vs.string tension

[martin swan]

18 minutes ago, Marty Kasprzyk said:

When I put a new string on and turn the pegs to bring it up to pitch it starts with a low pitch and low loudness note and as I turn the peg the notes get higher in pitch and louder as the string tension increases.

Am I the only one who notices this loudness increase or is this just my ears and brain not working again.

 

 

You can't bow a floppy string either fast or hard. As the tension increases we can bow a louder note without detuning the string or making it squeal.

We don't tend to notice the micro-adjustments our body makes when playing - a great example is if there isn't enough bridge curvature to give good clearance on for example the D string. Players complain that the string sounds weak, but in fact they are automatically compensating for the lack of clearance by paying more cautiously on that string. Sort out the clearance issues and hey presto, the strings balance ....

[LCF]

4 minutes ago, martin swan said:

You can't bow a floppy string either fast or hard. As the tension increases we can bow a louder note without detuning the string or making it squeal.

 

So higher tension strings play louder?

[martin swan]

23 minutes ago, LCF said:

So higher tension strings play louder?

What does that mean : "play louder"? Whatever it means, higher tension strings might achieve this on some violins.

And we haven't even got into the question of whether you actually want more SPL. Most violins sound so nasty the less sound the better.

[ctanzio]

There was a question about the energy of a vibrating string. The derivation is a bit involved, so I will just give the final equations here as they illustrate the parameters that affect the sounding of a violin string.

 

A violin string can potentially vibrate with any of a series of harmonic frequencies, call them f(n), n= 1,2 3,4...

f(n) = (n/2L) x sqrt(T/m)

L = string length

T = string tension

m = mass per unit length

 

Then for any harmonic frequency, f(n), and amplitude of that frequency, A(n), the string energy is:

E(n) = pi^2 x f(n)^2 x A(n)^2 x m x L

pi = pi (3.14159...)

f(n) = nth harmonic frequency

A(n) = amplitude of nth harmonic frequency

m = mass per unit length

L = string length

 

The total energy in the string is the sum of all the harmonic modes of the string which will simplify to some factor times the sum of the square of the amplitudes of all the harmonics.

Here is where reality intervenes and makes a mess of things. 

A violin string does not vibrate as an ideal, symmetrical string. There is a mostly symmetrical vibration of the first harmonic. But there is also a humped shape wave that travels back and forth between the nut and bridge as a pulse due to the slip/stick motion caused by the bow.

Now factor in the damping inherent in the string material then the actual amplitudes of each harmonic, A(n), becomes a real challenge to nail down.

 

I think the energy of the first harmonic might be good enough to get a feel for how the various string parameters affect the string's ability to drive the bridge. Substituting f(1) int the energy equation we get:

 

E ~ (pi/2)^2 x A^2 x T / L

 

String  energy, and by extension, loudness, varies as the square of the amplitude, or bow pressure to pull the string before it slips, and the tension of the string.

If one is testing different tension strings, one must be careful to bow them in such a way so that they are vibrating at the same amplitude. Otherwise you are only testing your bowing arm, not the strings.

 

[Anders Buen]

3 hours ago, LCF said:

Well 3 dB is twice as loud.

Only in terms of energy, but not subjectively. Then you need 10dB to get a doubling of the perceived sound level, or a halving if you go 10 dB down. Loudness is a subective psycoacoustics metrics.

[Michael Darnton]

6 hours ago, Violinnut said:

I just changed my e string. The one at first was very strong one (.28) I put a lighter one that had less pressure and it actually helped the tone, I can not say that it was not as loud, but it sure helped the D and A string. It now sounds much better.

By the way, would more pressure also not destroy some of the upper harmonics. 

Yes, we often do this dance in our shop. We have an E string that we really like for the E sound, but it often messes with the other strings and trashes them. And sometimes the opposite, too. You just need to do the work to discover the results on every violin. The interesting thing is that it's theoretically a medium-gauge string, so there shouldn't be this change.

[LCF]

10 minutes ago, Anders Buen said:

Only in terms of energy, but not subjectively. Then you need 10dB to get a doubling of the perceived sound level, or a halving if you go 10 dB down. Loudness is a subective psycoacoustics metrics.

I suppose that would be from the $100,000 viola. 

[Michael Darnton]

1 hour ago, martin swan said:

You can't bow a floppy string either fast or hard.

There's another place where this type of effect comes into place that demonstrates the nature of the problem that it isn't simply a problem of the violin's native abilities but can be an unexpected result of the setup.

I often get customers complaining that their D string is quiet relative to the other strings. When I check I find that the bridge was probably originally cut for an aluminum D and they have switched to silver Ds. The silver string is thinner, so it sits lower in the notch. Because that puts it relatively low relative to the A and effectively also boosts the A height, relatively, they can no longer bow as hard on the D string without fouling the G and A. They reflexively back off when on the D and perceive this as the violin being weaker on the D. Bringing the D back into its proper height relative to the A solves the problem

[Anders Buen]

15 hours ago, Marty Kasprzyk said:

Have you tried putting a regular violin bridge on a Hardanger  and use standard EADG violin strings to see if its short string length was causing the difference in dB or if the difference was due to other things in a Hardangerfiddle's construction?

Yes, https://www.researchgate.net/publication/325392479_THE_ACOUSTICS_OF_THE_HARDANGER_FIDDLE

One of the test series was posted here on MN. I did not have the dominants om the HF version, but it is not unusual to play with violin strings on HFs is some use. The Grieg Opus 72 «Slåtter» with my father Knut Buen, and Einar Steen Nøkleberg is played on a HF tuned in A to work with the piano. It is a set of weich Pirastro Spiroccore steel strings on it. 

While we learnt to play, we had such steel strings on the HF as it will stay longer in tune that way.

Could have investigated this further, but are into other projects now.

https://grappa.no/no/albums/simax-classics/grieg-slatter-op-72/ the recording is on Spotify for the curious.

Edited March 29 by Anders Buen
Corrected the string brand name

[Victor Roman]

1 hour ago, martin swan said:

And we haven't even got into the question of whether you actually want more SPL. Most violins sound so nasty the less sound the better.

That is indeed a good point, Mr. Swan only I would change it thus : "Most ( French ) violins sound so nasty the less sound the better". 

[Victor Roman]

1 hour ago, Michael Darnton said:

Yes, we often do this dance in our shop. We have an E string that we really like for the E sound, but it often messes with the other strings and trashes them. And sometimes the opposite, too. You just need to do the work to discover the results on every violin. The interesting thing is that it's theoretically a medium-gauge string, so there shouldn't be this change.

Mr. Darnton, early in my "career" I used to tune and do minor repairs on pianos and I noticed the steel of the string, thickness being same, made a huge difference. I did notice the difference among various brands when it came to violins but I can not say I payed attention ( or noticed ) how it affects the other strings. Bit late for that now.

Nowadays, I am very happy with the E from the Dominant set. I wish the Tonica ( I like those ) set would come with the Dominant E.

[martin swan]

1 hour ago, Michael Darnton said:

 

I often get customers complaining that their D string is quiet relative to the other strings. When I check I find that the bridge was probably originally cut for an aluminum D and they have switched to silver Ds. The silver string is thinner, so it sits lower in the notch. Because that puts it relatively low relative to the A and effectively also boosts the A height, relatively, they can no longer bow as hard on the D string without fouling the G and A. They reflexively back off when on the D and perceive this as the violin being weaker on the D. Bringing the D back into its proper height relative to the A solves the problem

 

2 hours ago, martin swan said:

 

We don't tend to notice the micro-adjustments our body makes when playing - a great example is if there isn't enough bridge curvature to give good clearance on for example the D string. Players complain that the string sounds weak, but in fact they are automatically compensating for the lack of clearance by paying more cautiously on that string. Sort out the clearance issues and hey presto, the strings balance ....

Damn it Michael, we are telepathically connnected!

[Victor Roman]

17 hours ago, Michael Darnton said:

I think that I have mentioned here previously that I ran into Aaron Rosen in Korea and he said that he was using light gauge Dominants on the road in weird weather because they gave him the type of gut-like sound he wanted without gut's instability, and at no loss of volume. He was competing against a full orchestra in that rehearsal and doing just fine.

Did you mean Aaron Rosand ?

I ask because from the orchestra I noticed once or twice a strange "buzzing" quality in his tone. I never heard him from the perspective of the public. Ferras' tone was very underwhelming from the orchestra but nothing short of a wave of sound, in the hall. 

[martin swan]

18 minutes ago, Victor Roman said:

That is indeed a good point, Mr. Swan only I would change it thus : "Most ( French ) violins sound so nasty the less sound the better". 

Funny, I have yet to find a player who can identify a French violin with a blindfold on 

My experience is that if you take a large enough sample, the probability of an Italian violin sounding really bad is greater than for a French violin.

 

[reguz]

I think there is a big misunderstanding with the concept of loudness. Loudness may not mean how much sound is produced but says nothing about how far the sound radiates. There can be a lot of sound at the player's ear but little sound reaching out into a large hall. What then are we talking about? Well, when an instrument acts like a pump, i.e. sucks in and blows air out, it has a pump function. How can it do that? String tension produces arching shape changing on the instruments bout area. The bouts begin to bulge and the volume in the violin body changes by the action produced by the strings. Both the belly and back plate bout shapes changes, which thereby produces a volume change. These bouts have a state of tension that can be compared to the property of a spring. If the tension changes, the shape of the spring changes. If you continuously change the tension, the shape of the bouts changes. This is one of the functions to control. An optimal condition is achieved when the tension on the strings puts the bouts in a specific condition where the spring property is in optimal state. Thus the condition that no or very little creep becomes produced. If you manipulate the state of tension on the strings by replacing with a string that requires more or less tension, you can achieve an optimal state in the bout shapes. But unfortunately it is the case that the tension state of two or three can be optimized but not the fourth bout. We then have to do with the shape of the bout material property and the thickness we have given the bout. Nothing is more complex than understanding how it works optimally and how we can influence it. Perhaps the most difficult is for the D and G string to get the best result and string suppliers have several options to change so you as a builder can try it out.

But for these, other properties also apply that affect how the result turns out.

Along the arch between upper F-holes from end block to end block, can be considered as a beam on four supports.

The middle two have support (fix) by the sound post and the structure in the smallest cross-section at the place between upper F-holes. They allow very little movement when the two outer supports the  end blocks move when the instrument enters the dynamic state. These two move up/down and in/out. The sound post do not move in the static conditions that arise by string laod.

What we have to optimize is the movement that occurs when the fields between these fixed and moving blocks affect structures between them. The two at the far end produce an outward/downward movement while the one in the middle produces a downward/upward thus the opposite movement. There is a question of how movement balance is achieved between these three fields all depending on structural stiffness.

A problem with the blocks is that they do not function as hinges. Depending on how we design the length curve along the arch, that connection can become very stiff, which does not allow hinge deformation.

There may be an inflection point approx. 10 mm in front of the end block which means that along the arch there the structures starts its outward bending which is to be regarded as flexible and therefore that point is  to be regarded as a hinge. That characteristic is very important when it comes to getting a volume change +/- to start when the strings are attacked with the bow.

When all of this works optimally together with the above, you have a very good instrument.

[Michael Darnton]

20 minutes ago, martin swan said:

 

Damn it Michael, we are telepathically connnected!

Shoot, I missed that. Sorry. You were there first!

[Victor Roman]

7 minutes ago, martin swan said:

Funny, I have yet to find a player who can identify a French violin with a blindfold on 

That could be just because a certain amount of "nastiness" in tone is not noticeable in French violins, only. However, I would be amazed if a competent player could not distinguish between Maestro Perlman's Stardivarius and an ubiquitous French violin. Even from another room. 

[Michael Darnton]

18 minutes ago, Victor Roman said:

Did you mean Aaron Rosand ?

I ask because from the orchestra I noticed once or twice a strange "buzzing" quality in his tone. I never heard him from the perspective of the public. Ferras' tone was very underwhelming from the orchestra but nothing short of a wave of sound, in the hall. 

Yes. Might blame autocorrect.Typing with one hand these days and inattention. New shoulder, though!!! YAY!

[Victor Roman]

15 minutes ago, martin swan said:

My experience is that if you take a large enough sample, the probability of an Italian violin sounding really bad is greater than for a French violin.

I simply don't know, you could be right. If you talk "upper echelon" violins only, then I believe the Italians win hands down. 

[martin swan]

48 minutes ago, Victor Roman said:

I simply don't know, you could be right. If you talk "upper echelon" violins only, then I believe the Italians win hands down. 

By "upper echelon" do you mean in price or quality relative to other makers from the same country?

54 minutes ago, Victor Roman said:

However, I would be amazed if a competent player could not distinguish between Maestro Perlman's Stardivarius and an ubiquitous French violin. Even from another room. 

If you're saying that most French violins aren't as good as the Soil Strad then I don't think you would find many to disagree with you. 

[Victor Roman]

7 minutes ago, martin swan said:

By "upper echelon" do you mean in price or quality relative to other makers from the same country?

I think what I meant was the top Italian names up to 1800 and the top French names up to.... whenever. I suppose what I meant was "in quality".

[David Beard]

Playing energy and sound energy aren't stored in the resting tension or mass of the strings.   They store into the deflected and mass and additional tension of the deflected and moving string.

These energies in the string are further just inputs to a complex chain of motions and energy build up and storage.  Only at the end of this chain of energy flow do we get the radiation of sound that directly relates to real and perceived loudness.

So, no.  There is no simplistic direct formula between string tension and loudness.

[Victor Roman]

16 minutes ago, martin swan said:

If you're saying that most French violins aren't as good as the Soil Strad then I don't think you would find many to disagree with you. 

That is not what I am saying. What I am saying is that a competent player will be able to tell which one is which, even when blindfolded. You will forgive me if my initial wording was confusing.

[martin swan]

1 minute ago, Victor Roman said:

That is not what I am saying. What I am saying is that a competent player will be able to tell which one is which, even when blindfolded. You will forgive me if my initial wording was confusing.

OK, well I don't suppose anyone would disagree with that either - though if you're in another room then I would assume your hearing ability is more relevant than your playing ability. 

[baroquecello]

Here is the video I was talking about Brinton Smith is a fantastic cellist and plays a great instrument. The three string combos with their respective tensions tried out in this video are "Dominant ForteA/Forte/Medium/Obligato C 50.8 Oliv Heavy set total- 58.45 Rondo Exp A/Jargar Evoke D/JE G/Rondo C total 59.9" 

 

read his "the reveal" comment lower down. Entertaining!

 

so yeah, I think some of the math here has very little relation to real world acoustics.