Bass bar placement.

[stradofear]

I would agree with you that "Modern" violins don't vary that much, but from my recollection, Stradivari varied his f-hole upper eye openings by 6 + mm or so. Today next to no one does that since they use a standard bridge size.

. . . .

What do you aim for?

I don't think we have evidence as to what bridge sizes he used on those violins, but modern restorers mostly, as far as I'm aware, generally use normal bridge widths on them. But I thought we were discussing bar placement relative to the outline, not the f-holes? From a practical standpoint, what you basically need is for the bridge to be sitting on the bar, rather than punching a hole in the top next to the bar, whatever bridge you choose to use. Me, personally, I haven't gotten the mileage I would have wanted (or was promised by various writers) by moving the bar in and out for adjusting things, so. . .

I use 12 and 15mm, then check that I'm 1mm inside of the bridge, and if the direction of the grain of the wood allows it, I tilt the bar more towards straight, dead straight to the centerline, if possible. Aside from disrupting the holy modes, risking the wrath of the violin gods, this seems to work better, in general, in my experience.

As I commented before, more angle = less desirable, in my experience, though I doubt that someone who's not been given the choice of the two settings would notice the difference if he hadn't had the experience of playing them both. The best description I can give is that pressing hard with a normal bar, you get the feeling that you press harder and the violin will continue to move more (even though it might lapse into distortion). With a too-angled bar there's a feeling of a wall just beyond your playing pressure that is going to limit what you can do; even though it's beyond where you are playing, you can feel it pressing back, limiting things.

[NewNewbie]

I don't think we have evidence as to what bridge sizes he used on those violins, but modern restorers mostly, as far as I'm aware, generally use normal bridge widths on them. But I thought we were discussing bar placement relative to the outline, not the f-holes? From a practical standpoint, what you basically need is for the bridge to be sitting on the bar, rather than punching a hole in the top next to the bar, whatever bridge you choose to use. Me, personally, I haven't gotten the mileage I would have wanted (or was promised by various writers) by moving the bar in and out for adjusting things, so. . .

I use 12 and 15mm, then check that I'm 1mm inside of the bridge, and if the direction of the grain of the wood allows it, I tilt the bar more towards straight, dead straight to the centerline, if possible. Aside from disrupting the holy modes, risking the wrath of the violin gods, this seems to work better, in general, in my experience.

As I commented before, more angle = less desirable, in my experience, though I doubt that someone who's not been given the choice of the two settings would notice the difference if he hadn't had the experience of playing them both. The best description I can give is that pressing hard with a normal bar, you get the feeling that you press harder and the violin will continue to move more (even though it might lapse into distortion). With a too-angled bar there's a feeling of a wall just beyond your playing pressure that is going to limit what you can do; even though it's beyond where you are playing, you can feel it pressing back, limiting things.

If you are not 1 mm inside the bridge foot, then what do you do, or is it a case of that never happening?

I wonder if the bar needs to be angled some more if the top wood is not cut on the quarter exactly, or is on the soft side?

I know that "The 'Secrets' of Stradivari" has in it's catalog a whole range of bridge templates of different sizes, but one cannot be sure whether they were used for full sized instruments or not.

[David Burgess]

I see one flaw, and one un-necessity.

...The flaw is in the assumption that the 1:7 rule somehow requires something different in the way of a centerline.

I'm not sure I understand the response, because I don't recall anything in the description of the 1:7 strategy (in this thread) which involves any "assumptions "or "rules" or "requirements" for determining an operational centerline. The concept has been outlined already, but maybe a recap would be helpful.

Bruce mentioned that the strategy was based on Sacconi's observations.

The 1:7 ratio is one way of establishing the bar angle, based on upper and lower bout widths.

With the angle established, the bar can be moved laterally to align with the bridge foot, and this will allow it to accommodate various centerline, bridge width, bridge placement, and string path strategies and corrections.

[stradofear]

If you are not 1 mm inside the bridge foot, then what do you do, or is it a case of that never happening?

I wonder if the bar needs to be angled some more if the top wood is not cut on the quarter exactly, or is on the soft side?

Ultimately, what with multiple pencil line widths intervening (three for the center, one each for 12 and 15, one for the bridge, and then adding the width of the bar, etc., I let the bridge vs the bar be the final decider, that being the most important. Somewhere along the line I lose track of the 12 and 15--I've never even bothered to check how correct they are, since they're just my starting point.

I don't think you can really compensate for floppiness with the bar. The floppiness is crossgrain, but the bar basically runs lengthwise, 90-degrees from the direction in which support is needed. I've toyed with the idea of a bar with small outrigger strips for problem floppytops, but haven't done it yet. I'm doubtful that it will work.

I do know, from experience, that bigger, higher, thicker, and more tension can't save the day, and turning the bar angled also does not. The place I've gotten the most effect was with the post, believe it or not, following the handed-down advice of Peresson, who made some floppytop violins and compensated by putting the post outside the bridge foot 1mm (what it does is force more of the string pressure over to the bass side, preloading that side, making it act stiffer). That did work better than anything I did with the bar. The Tertis model viola, as designed, uses the same strategy. Radial reinforcement straps around the edge of the top can help, but tend also to add the same brick-wall effect as a turned bar.

These things aren't things I tried just once before giving up on them--hope springs eternal, and initially I believed all the lore I'd read about bars. . . and quite a few got replaced along the way. One particularly nasty instrument got five bars within a two week span, and it's far from the only repeat offender along the way.

[stradofear]

I'm not sure I understand the response, because I don't recall anything in the description of the 1:7 strategy (in this thread) which involves any "assumptions "or "rules" or "requirements" for determining an operational centerline. The concept has been outlined already, but maybe a recap would be helpful.

Bruce mentioned that the strategy was based on Sacconi's observations.

The 1:7 ratio is one way of establishing the bar angle, based on upper and lower bout widths.

With the angle established, the bar can be moved laterally to align with the bridge foot, and this will allow it to accommodate various centerline, bridge width, bridge placement, and string path strategies and corrections.

David, I was referring to this paragraph of NN's:

"From a restorers perspective, a violin might not have the center joint on the top as the center line of the instrument, and the neck line may not be in the center of the instrument.

The outline of the instrument can be distorted from years of wear n' tear.

So how do you measure 12 mm and 15 mm from what, on the inside of the plate of an old instrument?

This is why the 1/7th rule with a possible parallel shift works for them."

in which he's implying that the problem is different for new vs old violins. My comment is that either way, new or old, you have to find the center. You can't get away without calculating it just because the edges aren't there, and things are distorted, which was the "assumption" I inferred from his statement. I was not addressing anything else that's been said in this thread.

[NewNewbie]

in which he's implying that the problem is different for new vs old violins. My comment is that either way, new or old, you have to find the center. You can't get away without calculating it just because the edges aren't there, and things are distorted, which was the "assumption" I inferred from his statement. I was not addressing anything else that's been said in this thread.

I was just trying to point out that the process for finding the bridge location, and thus the bass bar location via the bridge foot, was an entirely different problem from new making were everything is under control, and restoring with an 'wild looking' instrument plopped down in front of you, and so you have different ways/rules for going about locating the bar. Both get the job done.

============================================================================

Should mention that these little tools come in handy.

Note line scratched into brass feeler gauge

I'll see if I can find the site that has a side view of these gauges.

They show how it works much better, if you have never seen one.

[polkat]

One would assume that a good repair person would take care of as much of that as would be possible first hand. I never assume that the glueline on older violins is also the centerline. I have had several that were not the same. That's why I always find the centerline first. In fact, I was taught to use the 1/14 rule rather then the 1/7th. Measure across the bouts (full width of instrument) at the widest spots and divide by 14, then come in from the same bout edge on the bass side by 6 divisions at both the top and bottom, while keeping the bar under the bridge foot (roughly 1mm in) and you are set. By the way, this usually works out to roughly 12mm and 15mm anyway, but it bypasses a possibly offset glueline problem (assuming the bout edges are in good shape) because it doesn't take the centerline into accout to find the proper measurement.

[Bruce Carlson]

I'm not sure I understand the response, because I don't recall anything in the description of the 1:7 strategy (in this thread) which involves any "assumptions "or "rules" or "requirements" for determining an operational centerline. The concept has been outlined already, but maybe a recap would be helpful.

Bruce mentioned that the strategy was based on Sacconi's observations.

The 1:7 ratio is one way of establishing the bar angle, based on upper and lower bout widths.

With the angle established, the bar can be moved laterally to align with the bridge foot, and this will allow it to accommodate various centerline, bridge width, bridge placement, and string path strategies and corrections.

1/7th of half the width or 1/14th of the entire width is like the saying, "six of one and half a dozen of the other". Sacconi, in his calculations, took his measurements from the outside rib line and not from the edge as the edges are often worn in older instruments. If you look in the Sacconi book on his diagram you will see this. This is intended to give you an angle and only an angle. If Sacconi in wanting to show how he oriented his bass bar needed a position slightly further out or in he could just as easily have used finer increments such as 28ths, 56ths, 112ths, or 224ths for the divisions; all of which will give you the same angle. He naturally reduced the fraction for working convenience and mathematical convention. I don't think that anyone is obliged to use this sytem but it is interesting to note that Sacconi's observations stem from footprints left by the original bassbars along their gluing surface. It tells us something more about what Stradivari was doing and this in itself is interesting to me.

In the end I think David is underlining that setup is NOT JUST THE TABLE but the WHOLE INSTRUMENT from upper nut to the end button. To take into consideration how to position or align your various components between these two points is to have a complete overview of your setup.

Bruce

[Stacey_Styles]

1/7th of half the width or 1/14th of the entire width is like the saying, "six of one and half a dozen of the other". Sacconi, in his calculations, took his measurements from the outside rib line and not from the edge as the edges are often worn in older instruments. If you look in the Sacconi book on his diagram you will see this. This is intended to give you an angle and only an angle. If Sacconi in wanting to show how he oriented his bass bar needed a position slightly further out or in he could just as easily have used finer increments such as 28ths, 56ths, 112ths, or 224ths for the divisions; all of which will give you the same angle. He naturally reduced the fraction for working convenience and mathematical convention. I don't think that anyone is obliged to use this sytem but it is interesting to note that Sacconi's observations stem from footprints left by the original bassbars along their gluing surface. It tells us something more about what Stradivari was doing and this in itself is interesting to me.

In the end I think David is underlining that setup is NOT JUST THE TABLE but the WHOLE INSTRUMENT from upper nut to the end button. To take into consideration how to position or align your various components between these two points is to have a complete overview of your setup.

Bruce

I'll weigh in as a restorer, not as a maker. Personally, I use the 1/7 method to start but I also reference 19.5 from the center at the stop (measured between the notches). I start with a bar length of 7/9 the length of the top equidistant from the ends. I prefer 1mm inside the bridge foot. I think any of these methods are useful and when they are carefully considered, they are a sharp tool. Everything that lands on my bench is different and so I always ask myself "is there a concept here, on the part of the maker and/ or on the part of the person that last set it up (inc the bar)". Next question is how well does it work? Then what can I do to balance out some weakness, or enhance a strength. Ultimately, I am looking for a physical structure that works efficiently, so that the player's experience is that they are handling an instrument that is willing.

I find that when all other things are "right", then very small changes in things like bass bar placement (or neck angle or bridge cut or saddle height...) can make a big difference. I also think that the placement of the bar will greatly influence the future adjustability of the instrument in terms of set up - bridge,post etc.

Rules aside, I will move a bar laterally (especially depending on the arch) or change the slant slightly, trim wood off either end of the length, vary my shaping scheme, choose a stiffer or softer piece of bar stock....etc. I am talking about variations really very small in scope that I hope in combination will support my idea of what the instrument needs.

Ahhh, bass bars. One of the endless discussions!