Fingerboard top surface scooping.

[Elie H.]

Hello,

I am currently trying to draw an accurate representation of a violin fingerboard in 3 dimensions CAD, with the scooping already taken into consideration with the surface (because of the type of material I am testing my luthier might not be able to re-plane the fingerboard without damaging the instrument).

After reading some great discussions around this forum I learned a lot about the theoretical shape and scoop depths etc... But I still have some questions I couldn't figure out on my own. Sorry if my questions are too dumb.

1. Is it possible to have a symmetric scoop depth (E and G) instead of the typical 1:2 or 1:3 ratio and what would the main disadvantages be? I am thinking maybe something like 0.5mm could be enough for typical steel/synthetic strings.

2. Is the scoop depth measured vertically or in the radial direction (normal with the top surface)?

3. are other alternative fingerboard profile popular for violins (egg shaped, parabolic, two tangent circles, other curves) ? I couldn't find any references to this other shapes. maybe there's a good reason for that.

I know that this is a little bit subjective and dependent on a lot of other factors, but hopefully I'll be able to draw a surface that satisfy the needs of most players.

Thank you very much for your time and sorry for the long post.

Attached to this post are a picture of a fingerboard model, as well as a parametric 3d file if you're curious to change different parameters and see how they would look like.

fingerboard scoop parametric model.f3d

[Shunyata]

The geometry is a simple conic section.  If you use a constant radius of curvature at every point along the length of the fingerboard you will automatically wind up with a hyperbolic "saddle" around 1mm deep.  (I measure by putting a straight edge against the fingerboard surface and measuring the maximum gap.)

[duane88]

https://fixitwithshading.com/author/gummunq/

[nathan slobodkin]

19 minutes ago, duane88 said:

https://fixitwithshading.com/author/gummunq/

Yeah. A very interesting paper and absolutely correct that there are several ways to make a board. It makes a big difference if you have straight or curved sides on the board and by and large there is always some cheating to be done to get best playability.

[Elie H.]

11 hours ago, Shunyata said:

The geometry is a simple conic section.  If you use a constant radius of curvature at every point along the length of the fingerboard you will automatically wind up with a hyperbolic "saddle" around 1mm deep.  (I measure by putting a straight edge against the fingerboard surface and measuring the maximum gap.)

I found that if we assume constant radius across the length-it seems to be the most frequent choice for fingerboards-and account for a symmetric scoop on both sides, the closest geometric shape to the surface we get would be a section of a torus and taking the convex part of the torus.

My main (possibly false) intuition would be that this should be a great surface since, as you can see in the curvature map in the picture, the surface have a very consistent concavity.

10 hours ago, duane88 said:

https://fixitwithshading.com/author/gummunq/

 

Thank you for sharing MJ's work on this topic, I have been reading her very useful research on the topic and used it as a guidance to experiment with other various parameters. I have seen some values in the study that showed symmetrical scooping, But I have also seen a few answers that said they don't add any scoop which doesn't sound like a great idea. so I thought I would ask over here about the symmetry of the top surface, since her article is rather vague when it comes to this matter (she talks a little bit about side edge scoops being symmetrical but nothing about the top scoops.

A symmetrical scoop would help me tremendously down the line for this specific instrument, however it is not essential and if absolutely necessary I may compromise on this symmetry. However to me it doesn't seems like a violin would benefit from asymmetrical scooping as much as a cello or a double bass

It's rather surprising that her paper found no supermajority (50%+) for most questions, but the sample size may be small as well.

[duane88]

8 hours ago, Elie H. said:

 

It's rather surprising that her paper found no supermajority (50%+) for most questions, but the sample size may be small as well.

1- There has not been a source for training that has trained a "supermajority" of shop staff and makers, meaning that there has been no unified approach in instruction. Each group has their own ideas based on their lineage of training. In Germany you might find more agreement because of the schooling.

2-There aren't enough of us to have anything approaching a large sample group.

[Marty Kasprzyk]

I also believe in having good statistics--We need more people like MJ.

 

[Elie H.]

19 hours ago, duane88 said:

1- There has not been a source for training that has trained a "supermajority" of shop staff and makers, meaning that there has been no unified approach in instruction. Each group has their own ideas based on their lineage of training. In Germany you might find more agreement because of the schooling.

2-There aren't enough of us to have anything approaching a large sample group.

This makes sense, you're absolutely correct. But I wonder if this means there's no right or wrong scoop depth, if it's just user preference? this concept is so subtle I haven't heard about it once from the various musicians I know, and I didn't know about it either.

My best guess would be to have some scoop to facilitate playability and reduce potential interference, but not enough scoop to make the player feel that the string is too high. Am I missing something? MJ does say that she is not advocating for any option in particular, but could the changes we are talking about be so subtle? I will model some of the options highlighted in her study and post the curvature heat maps if anyone is interested.

Edited February 22, 2021 by Elie H.

[Shunyata]

I have made finger board with flat profiles and constant-radius curvature.  I don't see any difference in playability or interference with strings.  My opinion is that scoop is just an accidental artifact of constant radius templates.

[Marty Kasprzyk]

I put a new twist on this subject by making G side of the nut about 2mm higher than the E side with the fingerboard high at that end too as shown in the attached photo.

But the other end of the fingerboard and the bridge are kept level as normal.  The fingerboard therefore has a lengthwise twist to it.  This allows a little more comfortable hand position for fingering and the left elbow doesn't have to be tucked so far over to the player's right side while the bowing arm's movements are kept normal.  

Players like this twist but it takes more effort to get the correct scoop. 

 

[David Burgess]

1 hour ago, Shunyata said:

I have made finger board with flat profiles and constant-radius curvature.  I don't see any difference in playability or interference with strings.  My opinion is that scoop is just an accidental artifact of constant radius templates.

A constant radius template does not cause scoop. A good player needs the scoop. Without it, the angle at which the string departs from the fingerboard will be too shallow in the lower positions, resulting in a less clean sound, and buzzing when bowing aggressively or playing pizzicato.

[Elie H.]

56 minutes ago, David Burgess said:

A constant radius template does not cause scoop. A good player needs the scoop. Without it, the angle at which the string departs from the fingerboard will be too shallow in the lower positions, resulting in a less clean sound, and buzzing when bowing aggressively or playing pizzicato.

Is the asymmetry needed though? can the scoop be equal on E and G? and how much scoop is too much scoop? 

[nathan slobodkin]

 As Duane said different shops and schools use different specs. Good fingerboard shapes do not neccesarily have mathematically definable shapes. At Francais we made boards with quite a bit of scoop to the sides, a set radius at the lower end, a slightly smaller radius in the middle and a slightly larger radius at the nut. The lengthwise scoop was roughly equal to the diameter of the string above it. Some one who worked for Carl Becker told me that he actually made the "radius" slightly flatter on the E side to give a more solid feel and prevent the fingers from sliding off to that side. Trying to program a machine to make these shapes will be a real challenge especially on older instruments where small differences in neck width change the shape not to mention personal preference of different musicians.

[Shunyata]

I am an enthusiastic amateur, so pardon my ignorance about scoop.  The texts I have read (e.g. Johnson and Courtnall) seem to imply that scoop is "optional", not strictly necessary, but some players seem to prefer it.  I haven't seen that it is essential for talented, vigorous players.  (I can only vouch for myself, an untalented, vigorous player.)  Then again, I haven't tried to solo over a full orchestra.

I suppose a lot has to do with the nut height on the G string, too.  If you wanted a super low nut height, an extra 1mm of clearance in in the scoop could be important.  

 

 

[stringcheese]

Think of the outline of the space through which a string is vibrating. It's curved. The scoop (also called relief) is intended to match this curve (sorta).

[nathan slobodkin]

1 hour ago, Shunyata said:

I am an enthusiastic amateur, so pardon my ignorance about scoop.  The texts I have read (e.g. Johnson and Courtnall) seem to imply that scoop is "optional", not strictly necessary, but some players seem to prefer it.  I haven't seen that it is essential for talented, vigorous players.  (I can only vouch for myself, an untalented, vigorous player.)  Then again, I haven't tried to solo over a full orchestra.

I suppose a lot has to do with the nut height on the G string, too.  If you wanted a super low nut height, an extra 1mm of clearance in in the scoop could be important.  

 

 

Shunyata,

All of the shops I have worked in have put lengthwise scoop in the board. More "vigorous" players some times want more scoop but I have never had a player ask for none. I would definitely not consider it optional.

[Wood Butcher]

1 hour ago, Shunyata said:

I am an enthusiastic amateur, so pardon my ignorance about scoop.  The texts I have read (e.g. Johnson and Courtnall) seem to imply that scoop is "optional"

While that book may be useful when making your first instruments, I don’t think you can take what is in it as the last word on anything.
 

[David Burgess]

13 hours ago, Shunyata said:

I am an enthusiastic amateur, so pardon my ignorance about scoop.  The texts I have read (e.g. Johnson and Courtnall) seem to imply that scoop is "optional", not strictly necessary, but some players seem to prefer it.

 

Would you please quote what Johnson and Courtnall have written about this?

[Davide Sora]

On 2/22/2021 at 7:29 PM, Elie H. said:

Is the asymmetry needed though? can the scoop be equal on E and G? and how much scoop is too much scoop? 

I think the scoop is necessary, if only to prevent the fingerboard from becoming convex (the opposite of scooped). In fact, when it comes to wooden fingerboards, humidity plays a role, so if you make a perfectly straight fingerboard let's say at 40% ambient humidity, when it rises to let's say at 60%, your fingerboard will become convex and this would be a real problem.

With regard to the asymmetry of the scoop, it is not necessary but desirable to minimize the height of the E string along the fingerboard, that is, to ensure sufficient scoop for the G string and decrease it for the E string where an excessive scoop would make it "harder" to press with respect to the G string (and all other strings) as a sensation under the fingers. Of course the E string would also work with the same scoop as the G string, but it would be more uncomfortable.

Each fingerboard works with an appropriate string height (apart from convex ones) but some are more comfortable than others, and if you don't want too high strings the scoop is needed, in my opinion.

[Shunyata]

My bad.  It is Strobel that refers to scoop as a "non essential nicety". 

Johnson and Courtnall instructs one to produce a "hollow", no more than 1mm on the G string side - with some passing acknowledgement to making room for string vibration. 

J&C also talks quite a bit about assymetry in the radius and scoop, aiming for a subtle and efficient profile.

[Elie H.]

2 hours ago, Davide Sora said:

I think the scoop is necessary, if only to prevent the fingerboard from becoming convex (the opposite of scooped). In fact, when it comes to wooden fingerboards, humidity plays a role, so if you make a perfectly straight fingerboard let's say at 40% ambient humidity, when it rises to let's say at 60%, your fingerboard will become convex and this would be a real problem.

With regard to the asymmetry of the scoop, it is not necessary but desirable to minimize the height of the E string along the fingerboard, that is, to ensure sufficient scoop for the G string and decrease it for the E string where an excessive scoop would make it "harder" to press with respect to the G string (and all other strings) as a sensation under the fingers. Of course the E string would also work with the same scoop as the G string, but it would be more uncomfortable.

Each fingerboard works with an appropriate string height (apart from convex ones) but some are more comfortable than others, and if you don't want too high strings the scoop is needed, in my opinion.

Thank you for your detailed explanation Davide,

Let me add some information I didn't mention before since it didn't seems really important.

The fingerboard will be going on an electric violin made out of resin and out of a single piece, but for some technical reasons (aesthetic as well) It will be difficult to plane this fingerboard after it's manufactured without damaging it, at least I'm nearly sure no luthier would agree to touch this thing. Initially I did not put any scoop in the fingerboard saying that the luthier will add it later, but now it seems difficult to follow this path. this experiment is also rather costly from other ends as well so experimenting with lots of different dimensions might prove difficult initially. that's why I resorted to all the reading and opinions I could find on this topic, hopefully trying to nail it from the first (or second) try.

Here are some options from G-center-E (in mm) with an applied curvature map for visual help (since without that it's a bit hard to discern the difference), sorry for the huge size but I though it might be helpful for many to visualize how some of the smaller changes really impact the whole shape of the board. Dark blue is very convex, Light blue is less convex, and Green is flat. 

• 0.5/0.65/0.5 (same radius 41.5 mm all across the board)

• 0.5/0.55/0.25 (same radius 41.5 mm all across the board)

• 0.75/0.5/0.25 (middle radius 38mm like the 3rd option in the survey mentioned earlier )

• 0.5/0.45/0.5 (R38 in the middle)

• 0.75/0.65/0.25 (same radius all across like option 1 in the survey)

• 0/0/0 (same radius no scoop)

• 0.75/0.5/0.25 (R42/R33/R30)

• 0.6/0.4/0.2 (R42/R40/R44)

• 1/0.85/0.5(Same Radius)

• 0.7/0.7/0.5(Same Radius)

• 0.5/0.5/0.25 (Same Radius)

• 0.5/0.5/0.5 (R39 in the middle)

[Davide Sora]

If it's synthetic resin, you shouldn't have humidity issues, so I wouldn't put a scoop higher than 0.5 on the G and 0.25 on the E, and I would put 0.45 on the D and 0.35 on the A. I don't know if this makes sense geometrically, but it works for me. Making the curve by hand you can consider as four fingerboards under each string connected together by the overall curve, but since this is  strictly linked to the player's preferences it is difficult to say which could be the optimal solution.

Then, don't think your violin will end up in the hands of classical players, and I don't know what the preferences of non-classical players are regarding the bridge curve which is closely related to the fingerboard curve and originates it in a sense. It would be good to know who the violin is intended for in order to design an "optimal" setup and therefore the fingerboard curve.

[Elie H.]

2 hours ago, Davide Sora said:

If it's synthetic resin, you shouldn't have humidity issues, so I wouldn't put a scoop higher than 0.5 on the G and 0.25 on the E, and I would put 0.45 on the D and 0.35 on the A. I don't know if this makes sense geometrically, but it works for me. Making the curve by hand you can consider as four fingerboards under each string connected together by the overall curve, but since this is  strictly linked to the player's preferences it is difficult to say which could be the optimal solution.

Then, don't think your violin will end up in the hands of classical players, and I don't know what the preferences of non-classical players are regarding the bridge curve which is closely related to the fingerboard curve and originates it in a sense. It would be good to know who the violin is intended for in order to design an "optimal" setup and therefore the fingerboard curve.

I believe that what works for classical violin players should work for electric players , since most of them are classically trained. Maybe there's a distinction with fiddlers which prefer less scoop in general from what I understood. Thank you for your dimensions. very insightful. 

It is true that different players have different preferences, but I thought that maybe there's some scoop dimensions that would provide an optimal fingerboard for most players, leaving the customized solution for specific cases.

[DarylG]

12 hours ago, Davide Sora said:

I think the scoop is necessary, if only to prevent the fingerboard from becoming convex (the opposite of scooped). In fact, when it comes to wooden fingerboards, humidity plays a role, so if you make a perfectly straight fingerboard let's say at 40% ambient humidity, when it rises to let's say at 60%, your fingerboard will become convex and this would be a real problem.

Could you explain why the fingerboard becomes convex as the humidity increases?

[bungling_amateur]

On 2/22/2021 at 4:39 PM, Marty Kasprzyk said:

I put a new twist on this subject by making G side of the nut about 2mm higher than the E side with the fingerboard high at that end too as shown in the attached photo.

But the other end of the fingerboard and the bridge are kept level as normal.  The fingerboard therefore has a lengthwise twist to it.  This allows a little more comfortable hand position for fingering and the left elbow doesn't have to be tucked so far over to the player's right side while the bowing arm's movements are kept normal.  

Players like this twist but it takes more effort to get the correct scoop. 

 

Thank you for this Marty, we have an old fiddle with a warped / twisted neck, I always wondered why it didn't seem to cause any problems with playability... perhaps this is one reason it is so nice to play!