Brad H

Neck Overstand

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I know they are a critical factor in determining the angle of the strings over the bridge...but, are there other reasons, e.g., the needs of the  player, in varying the height of the overstand?   

David,  I am interested in whatever you would care to share about your rationale for the height of the overstands mentioned in another thread.

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My formula (for violins) is simpler.  Overstand = 6 - 6.5mm (from the Johnson/Courtnall book).  I figure that the player expects a certain relation between the body and the fingerboard, and I don't see any good reason to do anything out of the ordinary.

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4 hours ago, Brad H said:

I know they are a critical factor in determining the angle of the strings over the bridge...but, are there other reasons, e.g., the needs of the  player, in varying the height of the overstand?   

David,  I am interested in whatever you would care to share about your rationale for the height of the overstands mentioned in another thread.

Curious.  What thread?

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2 hours ago, chungviolins said:

I have a simple mathematically derived formula, which I've been using 20 yrs.

 

KYC

Sounds interesting...if it is simple, I can probably handle it. 

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4 hours ago, Brad H said:

I know they are a critical factor in determining the angle of the strings over the bridge...but, are there other reasons, e.g., the needs of the  player, in varying the height of the overstand?   

David,  I am interested in whatever you would care to share about your rationale for the height of the overstands mentioned in another thread.

The angle of the strings over the bridge isn't an overly critical thing; it's more or less pre-determined by the bridge height and the fingerboard elevation angle. The over stand measurement actually affects these two factors very little.

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12 minutes ago, Brad H said:

Sounds interesting...if it is simple, I can probably handle it. 

Very simple, for higher arch height you have to add extra mm to the overstand.

If you have same overstand for different arch heights, the string angle at the bridge deviates from 158 °, and the force on the top can be too much.( or too small)

 

KYC

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5 hours ago, chungviolins said:

Very simple, for higher arch height you have to add extra mm to the overstand.

If you have same overstand for different arch heights, the string angle at the bridge deviates from 158 °, and the force on the top can be too much.( or too small)

 

KYC

Of course that depends on the projection and the saddle height.  My question is hypothetical, if you increase the projection by say 10mm and get the angle at the 158 you like, what effect does the extra lever height of the overstand have on the top? How about the back? How does it effect the sound and string compliance? I sure would like Don’s input as well.

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5 hours ago, Bill Yacey said:

The angle of the strings over the bridge isn't an overly critical thing; it's more or less pre-determined by the bridge height and the fingerboard elevation angle. The over stand measurement actually affects these two factors very little.

 

I see things the opposite way round ... in my world the string angle determines the position of the nut and therefore the bridge height and the elevation. I know we've been through this a thousand times on Maestronet, but I still believe that this is the right starting point for any set-up, new build or old. 

But obviously we should clarify how we measure elevation. Since everyone's approach to edgework is different, I'm supposing it should be from the table surface to the top of the neck root at its extreme end closest to the bridge.

 

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2 hours ago, Jerry Pasewicz said:

Of course that depends on the projection and the saddle height.  My question is hypothetical, if you increase the projection by say 10mm and get the angle at the 158 you like, what effect does the extra lever height of the overstand have on the top? How about the back? How does it effect the sound and string compliance? I sure would like Don’s input as well.

Important number is string angle 158° . And this angle is determined by the three factors : neck overstand, fb projection (bridge height) and saddle height

If you have total freedom of neck setting, you can adjust br height and overstand to make the string angle 158° , adjusting saddle height is limited, you cannot make it too high or too low.

The overall effect of string angle is simple:

If it is smaller than 158° by more than .5° , too much downward string force, which chokes the sound and put the top under  pressure more than necessary. ( we usually say this strong angle, but angle itself ( number) is  smaller.)

If it is bigger than 158° , not enough downward force resulting less powerful sound.

Why 158° ?  :  It was empirically proven that 158° gives best sound by trial error for 300 yrs by thousands of makers.

This angle is very important : If you set the neck with fixed overstand ( if you don't adjust overstand) for a high arched vn, you make the string angle too small, which is not good for the sound but more importantly not good for the health of the violin.

 

KYC

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57 minutes ago, chungviolins said:

Important number is string angle 158° . And this angle is determined by the three factors : neck overstand, fb projection (bridge height) and saddle height

If you have total freedom of neck setting, you can adjust br height and overstand to make the string angle 158° , adjusting saddle height is limited, you cannot make it too high or too low.

The overall effect of string angle is simple:

If it is smaller than 158° by more than .5° , too much downward string force, which chokes the sound and put the top under  pressure more than necessary. ( we usually say this strong angle, but angle itself ( number) is  smaller.)

If it is bigger than 158° , not enough downward force resulting less powerful sound.

Why 158° ?  :  It was empirically proven that 158° gives best sound by trial error for 300 yrs by thousands of makers.

This angle is very important : If you set the neck with fixed overstand ( if you don't adjust overstand) for a high arched vn, you make the string angle too small, which is not good for the sound but more importantly not good for the health of the violin.

 

KYC

Sure, I understand your theory very well, but that doesn’t answer the question.  There are more things happening than just string angle.  Hypothetically, if you set the overstand to 16 mm and you make the other measurements so you have your exact 158, does the sound change, and if so, how?  You seem to be saying there would be no change as the 158 is the only critical aspect for sound.

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2 minutes ago, Jerry Pasewicz said:

Sure, I understand your theory very well, but that doesn’t answer the question.  There are more things happening than just string angle.  Hypothetically, if you set the overstand to 16 mm and you make the other measurements so you have your exact 158, does the sound change if so, how?  You seem to be saying there would be no change as the 158 is the only critical aspect for sound.

All I'm saying is too small string angle is not good for the sound and for the health of the top.

Makers set necks without considering this factor and making it too small angle, which is dangerous, you might get bigger sound but you lose quality and too much stress on the top.

16 mm is, of course , extreme, unless your arch height is 25 mm.

 

So simple formula :

Higher top arch ---> higher overstand

Example :    arch height 15  -->   overstand 7 mm

                                           16  -->                     8

                                           17 -->                      9

Of course you may adjust   above numbers by  +/-  .5°

 

KYC

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Just now, chungviolins said:

All I'm saying is too small string angle is not good for the sound and for the health of the top.

Makers set necks without considering this factor and making it too small angle, which is dangerous, you might get bigger sound but you lose quality and too much stress on the top.

16 mm is, of course , extreme, unless your arch height is 25 mm.

 

So simple formula :

Higher top arch ---> higher overstand

Example :    arch height 15  -->   overstand 7 mm

                                           16  -->                     8

                                           17 -->                      9

Of course you may adjust   above numbers by  +/-  .5°

 

KYC

Obviously, I am trying to understand if  there is reasoning behind this or just trial and error.  It would seem that raising the neck overstand in theory would both strengthen the top and back through the force of the overstand as a lever.  So in theory, the string angle should be able to get sharper over the bridge as the overstand increases and it is not just a static measurement.  Could one help an instrument with a week back by raising the overstand for instance.  I understand if it is just trial and error for you, I am trying to understand the underlying cause.  

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43 minutes ago, Jerry Pasewicz said:

Obviously, I am trying to understand if  there is reasoning behind this or just trial and error.  It would seem that raising the neck overstand in theory would both strengthen the top and back through the force of the overstand as a lever.  So in theory, the string angle should be able to get sharper over the bridge as the overstand increases and it is not just a static measurement.  Could one help an instrument with a week back by raising the overstand for instance.  I understand if it is just trial and error for you, I am trying to understand the underlying cause.  

String angle affects more on top than back.

The force will press down back, of course, but bc it goes thru sound post and maple is stronger, the net effect on the back is less than what it does on the top.

Yes, it has been my trial and error, but I did more than 500 neck sets using my guide lines, and it was proven to improve 0sound and response over and over. ( most of times I had to increase overstand, thereby increasing string angle)

If you measure the string angles of all your shop violins, it will be very close to 158°.

I used to collect data at the Kenneth Warren shop measuring hundreds of violins, interestingly enough, average of them was 158° .

I hope I answered it ok.

 

KYC

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Just now, chungviolins said:

String angle affects more on top than back.

The force will press down back, of course, but bc it goes thru sound post and maple is stronger, the net effect on the back is less than what it does on the top.

Yes, it has been my trial and error, but I did more than 600 neck sets using my guide lines, and it was proven to improve sound and response over and over. ( most of times I had to increase overstand, thereby increasing string angle)

If you measure the string angles of all your shop violins, it will be very close to 158°.

I used to collect data at the Kenneth Warren shop measuring hundreds of violins, interestingly enough, average of them was 158° .

I hope I answer it ok.

 

KYC

 

I am not arguing, I am sure everyone of the billions and billions that I have done work out similarly.  I am trying to understand the underlying mechanics.

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I seldom measure the angle at the bridge. When making new violins with normal archings of about 15 to 17  or so, I make the overstand 6 to 7. Any time I've checked the angle has been there or there abouts.

If you increase the overstand too much, and I've seen it done (9+) to violins with very high archings, you run the risk of encouraging the arching to fold up under the fingerboard, causing the elevation to fall. And some of the highest arched old violins are the very ones most susceptible to this problem. I suppose it's a balancing act. 

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39 minutes ago, martin swan said:

Jerry, both you and David have mentioned the notion of a lever in relation to the overstand.

Can you explain this to me - it's not actually something I've come across before.

I will try,  but as you can tell I am working on understanding as well.

An arch, any arch, will remain standing under force from above as long as the ends of the arch are fixed (a pedestrian bridge for instance).  When one or both ends are no longer fixed, the arch can collapse; conversely, if there is pressure pushing against one or both ends, the arch will strengthen......okay we all know this.  So, if the neck were glued to a static unmoving button, the overstand acts as a lever pushing against the top arch essentially doing the same as a pedestrian bridge..strengthening the arch (let’s leave the back out of this for now). As you increase the overstand, you increase the lever.

When I worked in New York, the man I worked for would say that so many bass bars are replaced because of a lack of understanding a neck set.  He would get instruments in that others exclaimed needed bass bars (because they were “played out” ) and we would reset the necks with higher appui and projection and the instruments would have the power and strength that they were missing.  To further explain this, I was putting a soundpost in a Stefano Scarampella viola.  Once the post was in and the instrument was strung up, I went to check the tension and the post was quite a bit looser than than I had made it. I unstrung the instrument, and once again the post was tight. Something was happening with the string tension that was causing the distance between the back and top to increase above and beyond the pressure pushing down on the bridge.  I do not know if this is a desirable characteristic, although the viola sounded incredible, but it demonstrated that the old French guy I worked for maybe had a lot more going on than an accent.

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5 hours ago, Jerry Pasewicz said:

Of course that depends on the projection and the saddle height.  My question is hypothetical, if you increase the projection by say 10mm and get the angle at the 158 you like, what effect does the extra lever height of the overstand have on the top? How about the back? How does it effect the sound and string compliance? I sure would like Don’s input as well.

Higher overstand would increase the longitudinal force on the top, and decrease the downward force at the bridge.  I didn't bother to calculate, but I think the longitudinal force would change more than the bridge force.

I see a lot of the usual arm-waving ideas about static forces and their supposed effect on sound, for which I have yet to see any solid verification.  Theory says static forces don't matter for vibration, in general.  My radical "downforce experiment" somewhat confirmed this latter view.

I'm with Connor in this... keep overstand to normal dimensions, and there's no point tuning the break angle to some precise value.  I likewise don't diddle with saddle height, just keeping to normal values so the tailpiece comfortably clears the top (with a high arch, I suppose you might need to increase this a bit).  I don't mess with very high arches any more, but if I did, I might also want a slightly shorter bridge (but then, there's the increased tendency for bridge projection to fall on high-arched fiddles, so maybe that's not a great idea).

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Jerry,

 I think the results of raising the appui are somewhat temporary as the increased lengthwise pressure on the top from the higher appui  tends to bulge the top under the FB as Conor pointed out. I think getting instruments to a state of equilibrium where  they move back and forth between two acceptable extremes when affected by humidity is one of the most difficult parts of our job.

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Just now, Don Noon said:

Higher overstand would increase the longitudinal force on the top, and decrease the downward force at the bridge.  I didn't bother to calculate, but I think the longitudinal force would change more than the bridge force.

I see a lot of the usual arm-waving ideas about static forces and their supposed effect on sound, for which I have yet to see any solid verification.  Theory says static forces don't matter for vibration, in general.  My radical "downforce experiment" somewhat confirmed this latter view.

Thank you Don.

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Just now, nathan slobodkin said:

Jerry,

 I think the results of raising the appui are somewhat temporary as the increased lengthwise pressure on the top from the higher appui  tends to bulge the top under the FB as Conor pointed out. I think getting instruments to a state of equilibrium where  they move back and forth between two acceptable extremes when affected by humidity is one of the most difficult parts of our job.

Agreed Nate, nice insight.  I guess that is the purpose of the question; controlling the equilibrium.

 

 

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