ff holes questions

[ispirati]

What is a good ff holes (edge to edge) distance between upper eyes? And between lower eyes?

What is the effect on the tone when they are closer together? And further part?

And what is the effect of the ff hole inclinations? Up right vs. angled?

[Andres Sender]

There was an article in The Strad addressing this, let me see if I can dig it up.

[Oded Kishony]

ispirati,

very good questions-what kind of experiements would you do to find out this information?

Oded Kishony

[ispirati]

Oded... I am just working on my 2nd violin. I wish I have to the time and skill to conduct such experiment. In order to conduct such experiment, one would need absolute precision in the making of violins. Ideally, One would need to make many (I think around 8~16) identical (I mean identical down to the thickness, arch, and every aspect) top plates. Then carve same type of ff holes on each violin with different distance and orientatoin. Finally, one take the measurement and record them. Mean while, we have to assume the property of the wood is constant. If any one does conduct such experiment, it certain deserve be published. I am just an amature. It would probably take me 15 years to conduct such experiment.

Or maybe we can simplify the experiment by using flat spruce boards (Guitar tops could be good). Then carve ff holes of various types to be measured. This could possibily save some time. But I am not sure if this would alter the measurement perameters when the arching is ignored.

Oded.. are you interested in conducting such experiment?

I was not asking so much "detailed" answers. I was more or less refering to the general "direction" of the answers. How these attributes would effect the tones in a general term.

Most of the standard suggestions were setting the upper eyes 40~44 mm apart. I think it is to match the bridge width. But when I looked at Strad's dimension, I see many pre golden period Strad violins that are 37, 38 mm apart for the upper eyes. Same goes for Amatis. It almost seem to be an Amatese trait. But After 1700, Strad begin to gradually increase the gap to 40 then 42. After Golden period, then you see the trend of going slightly more conservative to 40 again. I may be just taking snap shots of individual violin and missed the big picture, since I have limited number of the violin photos.

However, one thing does seem to correlate. Most of the more famous instruments tends to have wider and slightly more inclined ff holes, such as Strad Cremonese (an exception G?), and del Gesu Kreisler. Even the Strad Millanolo (a standard G?) is on the wider side. I wonder if this is why many suggests 40~44 being the "standard" eye to eye width?

[fiddlecollector]

The Soil`s `f` holes are more inclined than is usual for a Strad .The Delphino which is very like the soil also does. (the back wood is identical to the soil)

[nertz]

At violin making school I was told it was critical to keep the distance between the top holes over 40mm to get a great sounding violin.

Since then I’ve seen dozens of fabulous sounding instruments that break this rule, one of the best sound violins I’ve ever played on is the Gibson Strad of 1713 and I seem to remember that it has less then 38mm between the top holes.

[Jacob]

From my point of view the article, which I sudied in depth, promised more than it delivered in the sense that the distance between the eyes is not a neglected "silver bullet". To me it seemed to boil down to the fact that, within standard parameters, the position of the bass bar in relation to the eyes and the fit of the bridge feet to the bar (and also therefore the position of the post) are together much more significant that minor differences in the distance between the upper eyes.

What it meant to me was that if I made a Strad or del Gesu model with a distance between the eyes of 42 instead of 41 millitetres, it won't change anything tonally (all other adjustments being made accordingly, of course).

[Michael Darnton]

Most del Gesus have a 39mm spread, and no one feels they're inadequate. :-)

[fiddlecollector]

The Soil`s is around 38 1/2 mm.

[ispirati]

I just took a measurement in an extreme case during my lunch break. Strad "Joachim" 1698 has ff hole upper eye distance of 34.5mm. It is a long pattern.

There seems to be a pattern of progression in Strad's design. He went from Amatese ff holes (pre 1690), gradually incline them inward (1690s with long pattern), then move them appart and reverse to upright (1700 P models), then apart and incline (Golen Period G), and finally back to apart and upright again (Standard G). Is my observation correct?

[Oded Kishony]

Re: ff holes questions [Re: ispirati]

#264226 - 04/12/05 05:58 PM

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Tom King wrote an article in Strad Magazine not too long ago about his research into the Cremonese system of F hole placement. Anyone read it? The article is also on his web site

http://www.fiddleheadstrings.com/fiddlehea...d_dec04_007.htm

Ispirati-I was asking about possible experiments because it's wickedly difficult to compare such things. In the real world-the experiment you suggested would take years to complete and would not necessarily be conclusive.

I think there are two ways to get a sense of the effect; one is direct observation -the comments so far seem to indicate that the exact spread of the eyes is not critical-several instruments were cited with significantly different spacing that are said to be great sounding.

The other method, called 'finite element analysis' is a computerized model of predicting how something would vibrate having certain materials and shapes.

This technique might shed some light on what to expect but I don't think it would be conclusive either.

The violin is such a tricky, complicated thing-that's why I always say that for every rule I've seen about violin construction I've also seen a violin that breaks that rule and still sound terrific.

Oded Kishony

[Wolfjk]

Hi Inspirati,

Perhaps the ff holes work in conjunction with the arching, soundpost, bass bar, bridge position and plate thickness.

------Or maybe we can simplify the experiment by using flat spruce boards-----

A section of uniform flat piece of wood might not behave like a section from an arched plate.

The Question: what are the exact functions of the ff holes? should be asked here.

Cheers Wolfjk

[ispirati]

yes. I have read Tom King's article. I have been in contact with Tom about his placement method. It is very interesting. I would not say that I have mastered his method. And I no expert to judge whether he has broken the secret code or not. But it certainly generated good results for me. By using his method with the Betts example on my 2nd violin, I end up with a set of f holes that are identical to 1702 Conte di Fontana, with 46mm (center to center) upper eye, and 115mm (center to center) lower eye with a perfect 195mm stop length. Or you may translate that to 40mm and 106mm (edge to edge). This thread is really a follow up thread to my previos thread about Tom King's article a few weeks ago.

I recalled Perlman said in the ART OF VIOLIN DVD that Oistrakh's Conte di Fontana was not a particularly top Strad. So I turned my attention to the particular differences. So I took out all my violin photos and started to measure them one by one. I noticed that the famous "top" instruments all had wider and more inclined ff holes. I think even the del Gesu Alard was toward that spectrum as well.

According to Tom, there are many variations to the methodology by using different aspect of the Golden Ratio. The 1715 Cremonese is one of the example that the GS (Golden Section) position was Stradivarian, while the AB was Amatese, which end up with a wider lower eye and more inclined position. Well.. my logic is that I cannot go wrong with anything in the golden period. Although my pin positions do not follow the Cremonese methods, I could still use a set of imaginary pins to do the measurements.

Obviously, it took Strad years and years to conduct such experiment. But I think my simplified test by ignoring the arching may also yield some interesting findings. We could use guitar tops and laser cut some sample sets of ff holes to conduct the experiment. We may look for the effects of the wave propagation, overtones, damping, and antenuations of the waves.

Your suggestion of running a simulation with finite element analysis is very interesting. Back in school, computer simulation was my particular keen topic. Although I haven't done programing for years, I can already see the complexity of the code and the math even just thinking about the simulation macroscopically. Even before the programing begins, one would need several math PHDs to figure out the math of the waves within the top plates that bounce in and out of the boundry of the top plate, including the ff holes. The math alone is a nightmare. (Since LastChair is the only Math PHD that I know in this forum, maybe she can help out.) But I think it is probably faster for me to make those plates than to re-learn Fourier transforms math AGAIN.

However, another thing that bugs me is the stop length. I have small hands. So I prefer stop length of 193~195mm. Strad did not seem to have any standard Stop length in mind. By making the ff holes wider, and more inclined, the stop length would increase by 1~2 mm. If I want to have a Golden period ff hole, then I would end up with a 196mm stop length. Well.. the Cremonese is 197mm in the book. Maybe my fingers just have learn to live with it.

[ispirati]

Quote:

---

The Question: what are the exact functions of the ff holes?

---

The ff holes separtes a section of an "island" on the top plate that allows the top to vibrate more freely. If there is no ff holes, than the vibration coming from the bridge would have to vibrate the entire top plate, which is more difficult. Also, the ff holes allows the air within the soundbox to interact with the air outside the sound box, hence propagate the sound waves.

You can do a simple experiment by covering up the ff holes while playing. It will effectively mute your violin.

[Oded Kishony]

I don't think a flat plate will give a resonable approximation of an arched plate even for just studying the function of the F hole.

I think what you are currently doing is mostly likely the best way to study the question,unless you want to become an acoustical researcher. Try to include more variables- such as arching and set up in your considerations.

Oded

[Wolfjk]

Hi Inspirati,

Thanks for your post.

-----The ff holes separtes a section of an "island" on the top plate that allows the top to vibrate more freely. If there is no ff holes, than the vibration coming from the bridge would have to vibrate the entire top plate, which is more difficult.-----

Perhaps the bass bar is added to replace the wood you displace when you cut the bass side f hole, and the sound post is added to create an area between the bridge foot and post to aid the high registers?

Would it not indicate that the narrower "island" between the top eyes would result in stronger high notes and wider "island" between the lower eyes more defined lower notes?

Perhaps the structure of the belly wood should be taken into consideration.

I do not know where geometry comes into it?

Cheers Wolfjk

[Oded Kishony]

>Would it not indicate that the narrower "island" between the top eyes would result in stronger high >notes and wider "island" between the lower eyes more defined lower notes?

>Perhaps the structure of the belly wood should be taken into consideration.<

The role of the F holes is probably not as simple and linear as your description suggests.

The two areas that I'm somewhat familiar with are the air resonances and some high frequency behavior.

You can clearly hear the effect of air movement if you cover one F hole and hum a C# into the other, then uncover the other F hole. It is like turning a switch on and off. So, clearly the F hole is responsible for radiating the C# through the Helmholtz (named for a brilliant 19th century researcher) resonance. There are a few other prominent air modes (usually described as "A" followed by a number, with the Helmholtz resonance being A0 (zero) followed by A1-4 describing the various ways that air moves inside a violin. In A0 the air is moving up and down between the top and back, A1 between the top block and bottom block etc.

Back to F hole motion- At higher frequencies the F holes can radiate significant sounds from their edges. You can see the F holes going through a lot of motion at these frequencies and radiating significant sound. (go to Martin Schleske's site to see all this, under 'modal analysis') The thing to keep in mind is that every instrument is unique-they all follow certain general rules and patterns but there are many different pathways for the sound to radiate and each violin has a signature of it's own. That's probably why the violin is such a forgiving structure-as I've said before you can break many 'rules' and still have a wonderful sounding violin, yet if you happen to break the wrong combination of rules you get a screech instead of a song.

Oded Kishony

[Singingmaple]

I know that to this day the first violin I made is a better violin as far as sound goes than the 17 I have made since. My 1st violin has Huge,poorly placed and horrific looking F-holes that are only 35mm apart at the top.

It is not very nice to look at but boy does it sound good. I have tried to copy everything I did on that violin as far as arching and thicknesses but cannot get myself to make a F-hole that big or poorly placed.

The only way I can describe the difference is that it has a viola quality to it, It is much harder to play quietly than loud, If you so much as point a bow at it, it is singing. Also if I grab this violin around the C-bout and hold it with my arm stretched in front of me and talk at the right pitch it starts to vibrate in my hand and echoes my words back to me. Since I realized this violin does this I have tried it on all my violins. They all do it to a degree but not as pronounced as this one.

I am relatively new new to violin making compared to others on this board and do not have the experience with violins made by others or a School training to be able to explain my experience with this any better. I know there is a difference between my first and all the others I have made but have been unable to duplicate it yet.

[Oded Kishony]

Your description indicates that the violin may be too thin.

Does it have much of a wolf tone? Is the E string wiry and thin sounding rather than full and round?

Have you had anyone who is a good player try it? I suspect they won't like it much.

Probably the thickness right around the F hole is as important as the specific location.

A wide open F hole should produce more high frequency sound than low frequency sound.

Oded

[Craig Tucker]

"What is a good ff holes (edge to edge) distance between upper eyes? And between lower eyes?

What is the effect on the tone when they are closer together? And further part?

And what is the effect of the ff hole inclinations? Up right vs. angled?"

You know, this is the type of question I just love, because rarely does anyone ever think to ask such a question. I’ve been meaning to get to this question, but only just now found the time. I have mentioned here before that I consider the distance between the upper ff hole eyes is an important measurement and it is one that I pay close attention to in order to get the tonal response I want. I consider that the answer and the reasoning behind the measurement is fairly involved and some of my thinking is as follows:

Please feel free to critique - these are just my own working theories...

I believe that either 40mm or 42mm could be considered a modern "standard" measurement or a starting point for experimenting with upper ff hole eye distance.

The distance between the lower eyes isn't as critical as the distance between the upper ff hole eyes, because the distance between the upper ff hole eyes establishes the central strip where the belly wood is allowed to run uninterrupted, the entire length of the violin... as such, that measurement is critical.

I use the distance between the upper ff hole eyes (in conjunction with some other variables) to make my violins more powerful.

The distance between the upper ff hole eyes is one of those variables that presents a "window" where; too close together and too far apart both don't work well, but pressing the advantage to either the inner or the outer limit - without going beyond - can result in more power or less power, and corresponding changes in tone. The further apart the upper eyes are, the larger the uninterrupted effective soundboard area is, and the closer together they are the smaller and more concentrated it is. You could conceivably alter the measurement either way to your advantage, but, since I’m looking for a particular result, I move the eyes further apart.

Soundboard too large, and the bridge can't drive it efficiently - too small, and you loose some potential volume, so, I say that the upper ff hole eyes are a critical measurement for the tone of the violin and must be engineered correctly and in conjunction with all of the other available variables.

Since physics demands that nothing is free (energy wise), you always risk losing something whenever you look to maximize the power of the violin by altering any of the measurements very far away from the “standard” safe measurements.

For the sake of argument, I consider that 42mm is the standard distance between the upper ff hole eyes for my Strad model violins, and is the measurement from which you can vary either way without going too far astray.

So, when you consider changing that measurement, you must also consider altering the arch, thickness, string angle (bridge height), and/or whatever else you plan to do in order to accommodate the change.

For me, intuition plays a critical roll and I believe that you have to have a vision of the complete violin in order to make any changes that will work...

Part of the determining factor is the amount of downward pressure available, so, bridge height, string angle, and distance between the upper ff hole eyes all have to work together.

In order to understand how they work, you have to know what "standard" is, why it works to produce the tone we all attempt to capture, and then work closely within the standard guidelines to either maximize the measurements or minimize them in order to take advantage of the variables either way

I believe it works this way because, in a certain sense, the violin is an arbitrary construction where we are seeking to obtain a result that is going to fall within a certain tonal range that is also arbitrary or learned. The only reason why some particular construction method would be said to work or not work, would be that it would produce a tonal result that would be considered acceptable or not acceptable.

In all the talk I hear about sloppy or neat workmanship, this or that model, or whatever - some measurements are critical and others are not very important when it comes to tone. Varying the string angle one way or the other by a single degree is one of the important measurements, and moving the ff hole eyes further apart or closer together is another one that can have major consequences depending on what else is going on with the plates. Then bridge height plate thickness and arch. - if you concieve a violin where these factors work together, then you don't really have to rely on exactly copying someone elses idea where they have gotten those factors to work together.

[Oded Kishony]

Hi Craig,

>The further apart the upper eyes are, the larger the uninterrupted effective soundboard area is, and the closer together they are the smaller and more concentrated it is. <

Your entire argument is based on the sound being generated by the top- All the sound of the violin comes from the entire corpus up until about 1000Hz (around B above the open E string! ) So altering the behavior of the top will not have a very noticeable effect on the sound unless it changes the behavior of the entire corpus.

Oded

[Singingmaple]

It is actually very thick. I brought it to Dov to play and his first comment was that it weighed to much(and it does)

It plays very even no wolfs no squeaks. The E is very full, not even a hint of a metalic shrilly sound, it is my favorite part of that violin.

Dov said it sounded very good which suprised me. I didn't think he would like it for some reason and he's not one to hold an opinion to spare feelings. Trust me, he has squashed many of my works. I also had my daughters teacher try it out. she loved it, so much that she asked to play it in a concert at the church. Not a very big hall but it carried very well.

I havn't been able to figure out why it sounds the way it does. Everything on it is wrong according to books.

The violins that I make now sound good but are missing something that the first one has.

Jay

[Oded Kishony]

Bravo Jay

Another one of those violin acoustics mysteries ;-)

Oded

[Craig Tucker]

"So altering the behavior of the top will not have a very noticeable effect on the sound unless it changes the behavior of the entire corpus.

Oded"

In my opinion, it does. The top is where the major changes can be made. Isn't it?

[Wolfjk]

Hi Oded,

Thanks for your explanations. I shall have to have another look at Helmholtz studies.

------At higher frequencies the F holes can radiate significant sounds from their edges.------

Are these sounds produced or transmitted by the air inside the wood or by the framing of the cell walls?

Most experimenters treat the plate as a solid unit, yet looking at it from the structural point of view, the volume of a piece of spruce with a specific weight of 0.36 is made up of about 75% air and 25% of porous wood fibres. Would not leaking or radiating sound from the edges of the ff holes suggest that the air inside the wood transmits the sound?

Cheers Wolfjk