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Woodland

Boxy, honky nasal sound.

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6 minutes ago, Blank face said:

My experience is that things like falling soundpost or breaking strings when releasing the tension of the other three happen independent of a higher, lower or no overstand at all. In this way your experience might be different from mine.

My questions where different, too, and still unanswered. Just questions.

Of course they do, but I suspect you are intentionally missing the point.  Just being honest again.:D

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25 minutes ago, Jerry Pasewicz said:

Of course they do, but I suspect you are intentionally missing the point.  

Don't know. My point was that a violin top arching is different from semicircular bent rib (your example) and will probably react different. So the lever might not strengthen the arch, it could work different in the flutings, in thinner parts (where we often find deformations), it might press apart the sides (bouts) and many other effects you might not be able to take into account with a simplification. Releasing string tension moves the top, that's simple. It's less simple to know from where this movement originates and if it's really influenced (and if so, how much) by the overstand.

Another point are baroque violins without overstand. Following the "appui" theory these have much too less strengthening - or not?

 

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35 minutes ago, Blank face said:

Don't know. My point was that a violin top arching is different from semicircular bent rib (your example) and will probably react different. So the lever might not strengthen the arch, it could work different in the flutings, in thinner parts (where we often find deformations), it might press apart the sides (bouts) and many other effects you might not be able to take into account with a simplification. Releasing string tension moves the top, that's simple. It's less simple to know from where this movement originates and if it's really influenced (and if so, how much) by the overstand.

Another point are baroque violins without overstand. Following the "appui" theory these have much too less strengthening - or not?

 

Yep, which is why we are having the discussion.  I know my experiences and the experiences of the people that taught me.  Add up the experiences, add yours to the mix, and start to figure it out.  Just because we have questions and there are questions in your mind,  does not mean they are not worth figuring out.  You are not looking for answers, you are looking for reasons why we can’t ever understand the problems.

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20 minutes ago, Jerry Pasewicz said:

Yep, which is why we are having the discussion.  I know my experiences and the experiences of the people that taught me.  Add up the experiences, add yours to the mix, and start to figure it out.  Just because we have questions and there are questions in your mind,  does not mean they are not worth figuring out.  You are not looking for answers, you are looking for reasons why we can’t ever understand the problems.

That was a rather thought provoking.

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46 minutes ago, Jerry Pasewicz said:

Yep, which is why we are having the discussion.  I know my experiences and the experiences of the people that taught me.  Add up the experiences, add yours to the mix, and start to figure it out.  Just because we have questions and there are questions in your mind,  does not mean they are not worth figuring out.  You are not looking for answers, you are looking for reasons why we can’t ever understand the problems.

I can not find much logic within this, but possibly it's just very good disguised.

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if raising the overstand is beneficial how far can it be taken? If higher seems better on violins would 8mm be better? or 12mm?

One thing to think about is where the overstand is measured from. I always measure from the purfling upwards because I am often dealing with copying very old worn instruments. In reality I measure from purfling to top of the fingerboard edge on treble and bass sides to get a real picture of what is going on.

One thing to keep in consideration is the constants...BUT in reality if the 'Worlds greatest adjuster' decides the overstand is wrong  that needs strings off to fix and in reality the whole set-up gets re done and if done commercially well the violin will sound supercharged long enough for the customers cheque to clear

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9 hours ago, Blank face said:

Another point are baroque violins without overstand. Following the "appui" theory these have much too less strengthening - or not?

 

I don't think I've seen a baroque violin without overstand. I have seen many though where the overstand was achieved with the fingerboard, rather than having the neck protrude as far. The geometry can work out about the same.

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11 hours ago, Brad H said:

My understanding is that this "lever" idea says that the nut/overstand positions will influence how much of that compressive force is focused on each plate.

 

If the neck mortise is tight and the glue joint is firm, I just don't buy this. The top block will tilt forward in relation to the string tension, not the position of the nut. Nothing is pivoting ergo no difference in leverage ...

 

 

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8 hours ago, Melvin Goldsmith said:

if raising the overstand is beneficial how far can it be taken? If higher seems better on violins would 8mm be better? or 12mm?

 

I don't know how high it can be taken. I've heard people claim that the ideal falls within a certain range, but not that going higher than this range is better.

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44 minutes ago, David Burgess said:

I don't think I've seen a baroque violin without overstand. I have seen many though where the overstand was achieved with the fingerboard, rather than having the neck protrude as far. The geometry can work out about the same.

I could make it more precise and tell something like "baroque or transitional violins with a neglectable overstand in comparison to what we are talking about here", but the principle would be the same.

If the geometry is assumed to be the same, we would talk about 6 mm "overstand" plus ca. 5 mm fingerboard thickness at modern = 10-11 fingerboard thickness at baroque/transitional. There might be some like this, but probably not many, especially not from the late 18th and early 19th century period.

Now it's about height of the fingerboard surface, not neck overstand anymore.

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I could measure my transitional Hopf violin, but with the fingerboard being part of the "overstand" how do I know what to measure? Top of "box" to G-string maybe?

 

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18 minutes ago, Blank face said:

 

If the geometry is assumed to be the same, we would talk about 6 mm "overstand" plus ca. 5 mm fingerboard thickness at modern = 10-11 fingerboard thickness at baroque/transitional.

We could describe it either way. I think it is where the strings end up, relative to the body of the instrument that matters, when it comes to the forces involved.

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1 hour ago, martin swan said:

If the neck mortise is tight and the glue joint is firm, I just don't buy this. The top block will tilt forward in relation to the string tension, not the position of the nut. Nothing is pivoting ergo no difference in leverage ...

 

 

Try this Martin.  You know that there is compressive force on the plate right?  Meaning, when the strings are tightened the neck is pulling forward....so what would happen to that compressive force  when the strings are tuned a step high?  As far as the nut tilting forward, sure it does, just tune up a violin that the fingerboard has fallen off and the nut is there, what happens?  The nut pulls forward causing the neck to bend...

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102A268C-820F-44DD-B743-90D4E9E46A76.gif.a892e020894980a0729d7b4d30b39423.gif

What Brad H. Is describing:

The string tension is the effort, the top is the load, and the button is the fulcrum.  This is the model...there is also the fact that the back in theory stretches, but we should probably table that for now.:mellow:

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1 hour ago, Jerry Pasewicz said:

Try this Martin.  You know that there is compressive force on the plate right?  Meaning, when the strings are tightened the neck is pulling forward....so what would happen to that compressive force  when the strings are tuned a step high?  As far as the nut tilting forward, sure it does, just tune up a violin that the fingerboard has fallen off and the nut is there, what happens?  The nut pulls forward causing the neck to bend...

You are speed reading ...!

I mean that if the neck/top block/button joint is good and secure, then putting the strings under tension will tilt the top block forward in relation to the amount of tension, not in relation to the position of the nut.

The fact that a neck can warp under tension if it isn't supported by a fingerboard doesn't really have anything to do with anything, since violins have fingerboards.

Similarly you could speculate at infinitum about how a neck would pivot if it wasn't glued to the button, but since it's glued to the button there's no relevance to the speculation.

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38 minutes ago, martin swan said:

You are speed reading ...!

I mean that if the neck/top block/button joint is good and secure, then putting the strings under tension will tilt the top block forward in relation to the amount of tension, not in relation to the position of the nut.

Okay, I slowed way down my reading speed, and sure enough, this is still not true.  Look at the diagram above, the position of the “nut” in your statement with string tension applied, is the effort*.  If the lever is lengthened, the mechanical advantage is greater in relationship to the the load (the top).  The mechanical advantage is greater depending on the length of the lever with a given load.

* Maybe one of our engineers can chime in, I believe in reality this would be from where each string begins and not where the string turns at the nut.

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Martin, I think what Jerry is saying is easier to see if you exaggerate. Clamp the bottom half of the violin in a vise. Your objective is to crush the top lengthwise by grabbing the overstand and pulling it downward towards the bridge. Cut off the neck, and grab what sticks out of the overstand as a handle and pull it down, trying to break the top. Probably not possible. Extend the overstand out two feet so you can get leverage on the block ("lever", one of the basic machines: a force multiplier) , and pull down on that handle. Easy to break the violin. Replace your hand with a neck and some strings. Jerry maintains this force on the end of the top strengthens it. I'm not sure about that, myself. What Martin is saying is important about the relationship being discussed, that he hasn't told us.

Martin?

You can argue about where the pivot point is, precisely at the button or somewhere else--It doesn't matter much--but the obvious part is that the longer the lever (overstand) the more efficient 75 pounds of string pull is going to be at doing whatever it's going to do on the top.

On the other issue, overstand height vs nut position, imagine swinging a golf club. Jerry points out that your hand moves when you swing, you say it's the club head. You're both right, you're just describing the situation differently because you both believe that your focus is the right one. I ignore both and say that the important thing that's changing is string angle (the golf movement is focused on the shoulder, a fixed point like the bridge, and that's how your doctor would discuss the problem when you come to him with a sore shoulder), assuming that the board is pointed to the same bridge height. Jerry says the important part is forces acting on the end of the top, I'm not sure what Martin believes is important, where I think the important thing is the string angle, for a reason that hasn't been discussed, which is not downward pressure.

Because everyone's focus is different, they're seeing things from that position.

So Martin, I want to know why you say the position of the nut is important? Jerry is concerned with forces on the end of the top changing; what are you changing when the nut moves?

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1 hour ago, David Burgess said:

We could describe it either way. I think it is where the strings end up, relative to the body of the instrument that matters, when it comes to the forces involved.

"Relative to the body" is a bit neboulous. If I replace it with "height over the arching at the bridge position and angle there" this is close to the ideas Martin was describing, where the overstand is just one variable beneath others like nut, bridge or saddle.

 

 

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By the way, at one of the VSA conventions, in Kentucky, Rene Morel, talking about violas, said that players felt that the instrument felt stiffer with a lower bridge, floppier with a higher bridge. He didn't mention overstand or nut position. Just throwing that out here . . . . .

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To complicate things more, you should count in the parameters that defines the plates and top block, Thicknes, density and longitudal strenght of the plates and dimensions width and lenght of the top block, to be able to calculate the impact of the pull force to the top(and back) of the construction.  It will be different by changing those parameters.

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3 hours ago, martin swan said:

If the neck mortise is tight and the glue joint is firm, I just don't buy this. The top block will tilt forward in relation to the string tension, not the position of the nut. Nothing is pivoting ergo no difference in leverage ...

 

 

Martin,

Although my knowledge of physics is pretty limited it certainly looks to me that there is indeed a pivoting force at the neck root and long term deformation of instruments support this as we plainly see that there has been an upward pressure on the top plate and a stretching of the back resulting in a likewise upward pressure on the sound post. 

The longer the length of the short side of  the triangle  defined  by the flat side of the top, the nut and the top of the bridge the greater that rotation will be. That measurement certainly increases if the apuis is higher.

Edit:

As usual, in the time I took to write this several people have addressed this better than I did.

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Just as a reminder...

There is still no support from physics or experimental evidence that I'm aware of that says static forces have anything to do with the vibration behavior of the violin.  You may point out that string behavior will vary with static tension, but if you had a string that was curved and stiff enough in bending that it didn't straighten out, that argument goes away.

The one exception I know of is that a newly-applied static force will change the damping in wood, and very slightly affect the stiffness.  These effects go  away in a few weeks.

I would look to what is going on with the 3-D mode shapes, how they change with geometry changes in the body, how overall string tension and tailpiece movement interact with these modes, if I was going to get further into this fray.  Of course, if you want to look at all the modes, they would all be different, with different effects... so I think I'll just build new stuff with normal geometry rather than get into this rat's nest.

But carry  on...

9 minutes ago, Michael Darnton said:

By the way, at one of the VSA conventions, in Kentucky, Rene Morel, talking about violas, said that players felt that the instrument felt stiffer with a lower bridge, floppier with a higher bridge. He didn't mention overstand or nut position. Just throwing that out here . . . . .

Well, yeah... bridge height makes a direct difference in the vibration torque forces applied to the body, not to mention the potential mass difference.

You could also think of a higher bridge as allowing more mobility at the string contact point, or lower impedance, or "floppier".

 

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17 minutes ago, Michael Darnton said:

By the way, at one of the VSA conventions, in Kentucky, Rene Morel, talking about violas, said that players felt that the instrument felt stiffer with a lower bridge, floppier with a higher bridge. He didn't mention overstand or nut position. Just throwing that out here . . . . .

Yes, I have been around his terminology a great deal with former Rene workers, and with Rene when he was around, although “stiffer” is not the exact term I remember.  I think this was a difference in native language and translation.  I believe what Rene was talking about is the feeling of pull the strings had against the bow, the opposite of “skating” (although that term is also fraught with various interpretations).

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3 minutes ago, Don Noon said:

Just as a reminder...

There is still no support from physics or experimental evidence that I'm aware of that says static forces have anything to do with the vibration behavior of the violin.  You may point out that string behavior will vary with static tension, but if you had a string that was curved and stiff enough in bending that it didn't straighten out, that argument goes away.

The one exception I know of is that a newly-applied static force will change the damping in wood, and very slightly affect the stiffness.  These effects go  away in a few weeks.

I would look to what is going on with the 3-D mode shapes, how they change with geometry changes in the body, how overall string tension and tailpiece movement interact with these modes, if I was going to get further into this fray.  Of course, if you want to look at all the modes, they would all be different, with different effects... so I think I'll just build new stuff with normal geometry rather than get into this rat's nest.

But carry  on...

Well, yeah... bridge height makes a direct difference in the vibration torque forces applied to the body, not to mention the potential mass difference.

 

Thank you Don.  It is increasing evident to a greater and greater extent what we do is much more about how the player reacts to these changes and not what can be described through physics.  The player (and the bow...oh jeez the bow variable, that is a can or worms) is a huge variable.

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1 minute ago, Jerry Pasewicz said:

Thank you Don.  It is increasing evident to a greater and greater extent what we do is much more about how the player reacts to these changes and not what can be described through physics.  

Physics should also be able to cover what a player can feel and react to, if those things are actually real and not imagined.  It's just a different area, perhaps.  A lot of these things may be so complicated that it's easier just to do what is known to work, and not bother so much with the "why" of it all.  I'm a bit stuck with being a "why" person, but at some point I have to stop and cut chips.  

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