F- hole region - most sensitive spot on the violin?

[Andreas Preuss]

I remember that some years ago a high profile violin maker claimed in a Strad article that putting a 1g weight in a certain spot in the violin would bring out the desired over all sound quality. As far as I remember it was about getting the 'sizzle' in the sound. Of  course he didn't say where this spot is. 

Maestronetters are more open about their sound experiments. @Don Noon conducted an interesting experiment where he cut away the upper right f-wing with the result that the overall loudness improved but sound quality decreased .

Sam Zygmontovitch made in his Strad 3D film as well some comments on the area between lower f points and the c bout rim.

Last not least I remember having read an article which focused on the importance of the thickness around the f holes. It is known that if the area below the treble side f hole is too thin a wolf note can come out.

So how important is the region around the f holes for the sound quality and loudness?

Opinions?

Experiences?

 

 

[christian bayon]

Last but  not least I remember having read an article which focused on the importance of the thickness around the f holes. It is known that if the area below the treble side f hole is too thin a wolf note can come out.

 

treble side?

[Dave Slight]

I wouldn't make the wings too thin, or they might fly away

For wolf notes, I would be more concerned with the bass side of the belly being thin.

[Andreas Preuss]

11 hours ago, christian bayon said:

Last but  not least I remember having read an article which focused on the importance of the thickness around the f holes. It is known that if the area below the treble side f hole is too thin a wolf note can come out.

 

treble side?

Treble side ? Typical me. I mean left and say right. Bass side is correct. If it is too thin a wolf might come out. 

But besides that this zone is relatively easy to cut or scrape from the outside on the completed instrument in playable condition. In the end it doesn t matter if we make for example the fluting on the lower f wings before or after closing. If we can use it as a kind of fine tuning the better.

 

[Dave Slight]

An interesting idea.
I can't say I've noticed this on instruments from the golden times, but there is no reason why some thinning, or even some thickening at these areas won't make an audible difference. It will make a difference as to how the belly can move, probably over a wider area than just around the wing and lower eye.

[Don Noon]

Certainly the top of the bridge is the most sensitive spot on the violin; put a 1g mass there, and you'd get more change than anywhere else.  In order for the violin to make a sound at any frequency (driven by string vibration), that part of the bridge has to be moving.

It gets more complicated the farther you get from the bridge.  At a particular frequency, some parts of the violin move, and others are motionless.  At low frequencies, the bass foot of the bridge is moving the most, and generally the plates on the bass side are most active.  At higher frequencies, the treble foot is generally most active, and areas around it move most... particularly the upper wing of the F hole.  However, higher frequencies have lots of nodes and antinodes, and the pattern varies with frequency.  And, as an added complicating factor, adding mass to an area that moves will not necessarily have a logical effect, as the modified mode shape could become a more efficient radiator.

It's complicated.

But, yeah... around the F holes (and generally near the bridge) I think tends to make the most difference in sound.  Below the bass F moves most at the usual wolf frequency, so that is an area to concentrate on for wolf control... but it's a low-frequency mode, and takes a fair bit of mass/stiffness change to have an effect.

I'm almost making an argument for "tuning"... which I have not found to work well.  I hinted at one effect I have observed:  messing around with graduations to enhance of attenuate particular modes didn't change mode shapes or frequencies very much, and even if it did, things re-arrange themselves so that the sound doesn't change much.  Wood and arching seem to be far more controlling.

 

 

[Andreas Preuss]

@Don Noon Don, halfway I can follow your argumentation.

if you have a violin with a thin sound and the top is let's say 3.5 - 4mm thick and you reduce the entire thickness by let's say 15 percent you will hear a difference. So thickness matters. However, of your thicknesses are in down within certain stiffness parameters it doesn't matter so much if thin gown one spot. But then if you try to go from there to the absolute minimum it is getting extremely difficult to know where you still can take away material. It is clear if you go too far the sound will collapse.

Now if it comes to thickness changes in smaller areas,  I agree that for most locations you could almost scrape a hole without hearing a massive difference. I suspect that the areas around it will still give enough support. But this is not really the case on the rim of the f hole and therefore I suspect it to be more sensitive than other areas on the top. The upper treble side f wing is actually the only which can vibrate freely. The bass side upper f wing seems to be blocked by the bass bar and the lower wings on both sides are too far away from the center of action in the center and too close to the ribs.

Some makers in the past would scrape the treble side upper wing from the outside and the normal explanation is that after the sound post had been set the wing raised slightly above the surrounding surface and was leveled in from the outside. But maybe not and there was an adjustment intended.

On Strads we have the eyebrow effect over the f holes and the usual explanation is again some aesthetic enhancement. However this looks to me more like scraping at the closed box because if you go with the scrapet over the rim the surface will ripple up.

In the end the problem seems to be how we can design our thicknesses before closing the box so that we can hear alterations in playable condition on the closed box. If you leave for example by purpose as much as 1mm surplus on the thicknesses at the c bout and thin it down in playable condition you don't change only the thicknesses but also the arching. 

 

[Don Noon]

1 hour ago, Andreas Preuss said:

In the end the problem seems to be how we can design our thicknesses before closing the box so that we can hear alterations in playable condition on the closed box.

As a maker seeking to avoid unnecessary effort, and a tuner skeptic based on my experience and experiments... I prefer to design the thicknesses so that alterations are not necessary after closing the box.  Actually, it's more like getting the wood and arching good so that thickness doesn't matter so much, and lately that that seems to be working fine.  If the wood and arching are off, then no amount of thickness diddling will help much (unless you start with a 100 g top plate and take out 40 g).  I welcome any proof of tuning effectiveness.

 

 

 

[Andreas Preuss]

18 hours ago, Don Noon said:

As a maker seeking to avoid unnecessary effort, and a tuner skeptic based on my experience and experiments... I prefer to design the thicknesses so that alterations are not necessary after closing the box.  Actually, it's more like getting the wood and arching good so that thickness doesn't matter so much, and lately that that seems to be working fine.  If the wood and arching are off, then no amount of thickness diddling will help much (unless you start with a 100 g top plate and take out 40 g).  I welcome any proof of tuning effectiveness.

 

 

 

Don,

for this I think we need to talk about comparable sound measuring setup, otherwise all discussion about it would be more or less fruitless. I think you mentioned before that yours is not too complicated. What sort of mic are you using and some freeware for the graph analysis?

If it is not too expensive and too complicated I might think about doing it. 

[scordatura]

I believe that Don is using Audacity for his software. I also use Audacity and sometimes Sony Sound Forge. Audacity is freeware.

[Don Noon]

2 hours ago, Andreas Preuss said:

If it is not too expensive and too complicated I might think about doing it. 

Other than the computer, the net cost of my sound analysis setup was zero.

Audacity: free.   Cheapo computer microphone:  free (someone gave it to me).  Hammers I made out of scrap wood.

I did buy a fairly decent microphone, and I tried it for a while, but went back to the simple cheapo.  While the sound of the good mic is a bit nicer, the cheap one has a wide enough frequency band (and slightly more sensitive in the high frequencies), and all I really need is something convenient, simple, and repeatable(ish) to do comparisons.

[David Beard]

Hi Andreas,

I understand you're looking for possible ways to 'tune' the violin in hand after principle assembly.    

The sound holes do seem like reasonable candidates for this approach.   Thickness between the upper eyes, extension of the curves coming out from the eyes, shape and thickness of wings, thickness under and around the treble bridge foot, thickness in the middle of the island in front of the bridge, the width of the stems, fluting around the edge of the sound holes, and thickness left left out side the sound holes approaching the edges. These all seem like somewhat adjustable and somewhat active details you could try manipulating.   Also, thickness in the channeling seems a possible candidate for such efforts.  

But I'm very much inclined to believe the classical makers instead focused on tinkering with the design from one violin to the next, rather than 'tuning' the build in hand.

To me, setup is the natural place to adjust the current violin. Also, consider the efficiency of the different uses of effort.  A tailored setup is work that has to be done anyway. 

But the 'tuning' you seek is extra, and thrown away on the sense that such adjustments would require unique for every instrument. Something that setup already demands. In contrast, efforts spend on development across the iterations of your building stands to give more lasting and accumulating benefits.

Perhaps some of the things you're looking at might reasonably be treated as emergency extensions to set up-- measures best avoided when normal setup can get the job done, but available to the maker as last resorts with an instrument that isn't giving what you need?

[Andreas Preuss]

17 hours ago, David Beard said:

Hi Andreas,

I understand you're looking for possible ways to 'tune' the violin in hand after principle assembly.    

The sound holes do seem like reasonable candidates for this approach.   Thickness between the upper eyes, extension of the curves coming out from the eyes, shape and thickness of wings, thickness under and around the treble bridge foot, thickness in the middle of the island in front of the bridge, the width of the stems, fluting around the edge of the sound holes, and thickness left left out side the sound holes approaching the edges. These all seem like somewhat adjustable and somewhat active details you could try manipulating.   Also, thickness in the channeling seems a possible candidate for such efforts.  

But I'm very much inclined to believe the classical makers instead focused on tinkering with the design from one violin to the next, rather than 'tuning' the build in hand.

To me, setup is the natural place to adjust the current violin. Also, consider the efficiency of the different uses of effort.  A tailored setup is work that has to be done anyway. 

But the 'tuning' you seek is extra, and thrown away on the sense that such adjustments would require unique for every instrument. Something that setup already demands. In contrast, efforts spend on development across the iterations of your building stands to give more lasting and accumulating benefits.

Perhaps some of the things you're looking at might reasonably be treated as emergency extensions to set up-- measures best avoided when normal setup can get the job done, but available to the maker as last resorts with an instrument that isn't giving what you need?

Thanks for your comment on this. I am a bit sceptical about the way you view setup. I think it is a rather modern idea to adjust the last sound details with the cuto of the bridge, string selection etc. if makers in the 17th and 18th century adjusted anything it was the sound post and I think G.A. Marchi is discussing it in his book. 

The strongest reason for me to think that the area around the f hole was touched is the scraping above the ff leaving the eyebrow effect. I absolutely don't see any reason why someone would do it this way before closing the instrument. 

But I don't know yet if it was really done for acoustical reasons. Maybe. Maybe not. 

In any case I don't think any acoustic adjustments were done in single small spots but rather larger areas. So I am rather thinking of the entire  flanks. Since I have never done any violin in baroque setup I have no idea if this makes sense. It is possible though that a violin with a heavier neck and weaker strings and completely different bridge somehow reacts differently. Maybe it is necessary to draw a line between 'sound' and 'playability' where the first is only the sound spectrum and the second only how the instrument reacts under the bow. And maybe such an 'adjustment' had more to do with the latter. 

[Don Noon]

1 hour ago, Andreas Preuss said:

The strongest reason for me to think that the area around the f hole was touched is the scraping above the ff leaving the eyebrow effect. I absolutely don't see any reason why someone would do it this way before closing the instrument. 

I do... since that's the way I do it.  Final scraping after the F's are cut.

If you assume that the Cremonese finalized the outline and cut the purfling channel after closing the box (I believe that's the leading theory), then they would be doing quite a bit of external cleanup work with the box closed.  Whether there was also acoustic tuning at the same time is unknown, but seems extremely unlikely to me.

[Advocatus Diaboli]

17 hours ago, Andreas Preuss said:

The strongest reason for me to think that the area around the f hole was touched is the scraping above the ff leaving the eyebrow effect. I absolutely don't see any reason why someone would do it this way before closing the instrument. 

But I don't know yet if it was really done for acoustical reasons. Maybe. Maybe not. 

In any case I don't think any acoustic adjustments were done in single small spots but rather larger areas. So I am rather thinking of the entire  flanks. Since I have never done any violin in baroque setup I have no idea if this makes sense. It is possible though that a violin with a heavier neck and weaker strings and completely different bridge somehow reacts differently. Maybe it is necessary to draw a line between 'sound' and 'playability' where the first is only the sound spectrum and the second only how the instrument reacts under the bow. And maybe such an 'adjustment' had more to do with the latter. 

I've seen a couple makers get a very similar affect be placing their finger over the upper eye and scraping around that to preserve the sharpness of the FFs.

[Danube Fiddler]

On 10/5/2018 at 4:01 AM, Andreas Preuss said:

So how important is the region around the f holes for the sound quality and loudness?

 

On 10/6/2018 at 3:43 PM, Don Noon said:

But, yeah... around the F holes (and generally near the bridge) I think tends to make the most difference in sound.  Below the bass F moves most at the usual wolf frequency, so that is an area to concentrate on for wolf control... but it's a low-frequency mode, and takes a fair bit of mass/stiffness change to have an effect.

Perhaps read  "Experiments on the construction and the function of the violin " (Jansson; Niewczyk and Fryden - presented CASA 4.5.1991) :

Jansson et al made some experiments with thinning several areas of tops of assembled violins and watching frequency response (mobility) curves. Their findings have been : The thinnings along the side edges and of the center give little influence (on tone).  The most sensitive parts had been above and below the middle. A further finding was, that a bridge-hill ( if one wants it ) is quite independent of thinning/graduation - these violins, which had it, had it yet in very early states of assembled instruments. But these violins, which didn´t have it, couldn´t get it later by manipulations ( if I remember right). I don´t remember, if they also did evaluate by hearing comparisons (e.g. records of played violins, compared later ).

About the "wolf-area" below the left F-hole : my own sucess in avoiding wolves by building here thicker, was quite limited.

B.t.w. :  my own experiences in thinning the top - center have been a little bit different from the findings of Jansson et al., however only judged by hearing/playing. In my experiments the claims of Jansson et al about the areas below and above the middle were confirmed. But additional I observed a special influence of the middle area on something like the harshness of sound. After thinning the top center ( ~ - 2/10 mm ) the sound became more soft, particularly in the high-register. So my suspicion is, that a top center-thinning influences in positive way the responsive-curve-decrease "after"(above) the bridge-hill-region ( -> more decrease [ one of the Dünnwald -criteria ] ). However I assume, there could be two limits : static stability of the top-center and soloistic usability of the violin ( to soft = lesser individual sound-colour and more merging in surrounding ( accompagnying )sounds -  may be even lower possibilities of varying sound-colours ).On the other hand we can observe, that the most preferred old-italian instruments (in soloistic use) have quite thin top-center-areas ( < 3mm ). 

[Andreas Preuss]

On October 10, 30 Heisei at 6:38 PM, Danube Fiddler said:

 

Perhaps read  "Experiments on the construction and the function of the violin " (Jansson; Niewczyk and Fryden - presented CASA 4.5.1991) :

Jansson et al made some experiments with thinning several areas of tops of assembled violins and watching frequency response (mobility) curves. Their findings have been : The thinnings along the side edges and of the center give little influence (on tone).  The most sensitive parts had been above and below the middle. A further finding was, that a bridge-hill ( if one wants it ) is quite independent of thinning/graduation - these violins, which had it, had it yet in very early states of assembled instruments. But these violins, which didn´t have it, couldn´t get it later by manipulations ( if I remember right). I don´t remember, if they also did evaluate by hearing comparisons (e.g. records of played violins, compared later ).

About the "wolf-area" below the left F-hole : my own sucess in avoiding wolves by building here thicker, was quite limited.

B.t.w. :  my own experiences in thinning the top - center have been a little bit different from the findings of Jansson et al., however only judged by hearing/playing. In my experiments the claims of Jansson et al about the areas below and above the middle were confirmed. But additional I observed a special influence of the middle area on something like the harshness of sound. After thinning the top center ( ~ - 2/10 mm ) the sound became more soft, particularly in the high-register. So my suspicion is, that a top center-thinning influences in positive way the responsive-curve-decrease "after"(above) the bridge-hill-region ( -> more decrease [ one of the Dünnwald -criteria ] ). However I assume, there could be two limits : static stability of the top-center and soloistic usability of the violin ( to soft = lesser individual sound-colour and more merging in surrounding ( accompagnying )sounds -  may be even lower possibilities of varying sound-colours ).On the other hand we can observe, that the most preferred old-italian instruments (in soloistic use) have quite thin top-center-areas ( < 3mm ). 

Thanks for your detailed reply and sorry for answering so late because I couldn't load the MN page any more from my computer or IPhone.

I think all those alterations on the finished instrument are quite interesting because they don't change actually the fundamental sound characteristics. (For practical reasons I wouldn't try to adjust the area under the bridge)

I think, after reading all the contributions, it is more about playability than sound. But this is for high performance at least as important as the sound quality itself because it has a major impact on how the instrument feels under the bow. 

[Danube Fiddler]

9 hours ago, Andreas Preuss said:

Thanks for your detailed reply and sorry for answering so late because I couldn't load the MN page any more from my computer or IPhone.

I think all those alterations on the finished instrument are quite interesting because they don't change actually the fundamental sound characteristics. (For practical reasons I wouldn't try to adjust the area under the bridge)

I think, after reading all the contributions, it is more about playability than sound. But this is for high performance at least as important as the sound quality itself because it has a major impact on how the instrument feels under the bow. 

Your are welcome.

For practical reasons the bridge-area really is uncomfortable in outside-tuning while keeping the instrument stripped - I try to avoid it. About the effects I have difficulties to separate sound vs. playability. However I also recognized, that something special in sound stays, even after some considerable changes by tuning/ graduation-changes - while at the same time other things of sound/playability have definitely changed. There could be something like a fingerprint in sound, which changes nearly not in spite of really big manipulations. May be it is similar to the fact, that you will recognize a human voice in very different acoustical environments in spite of really great spectral changes because of room-acoustics. May be this is the reason, why regraduations of great antique instruments only rarely ruined them completely. Or why Don thinks, it doesn´t make sense at all to fine-tune instruments.