9 replies to this topic

[Giovanni Corazzol]

Hello, this is my first question on the Pegbox forum. I have tried a search but I haven't found any useful results about this.
My question is about violin bridges with non-standard widths, I mean, wider than the more usual widths of 41.5 and 42.0 mm.

Can we always expect better results with a wider bridge blank, when the f-holes and bassbar placement seems to require it (according to the classical Weisshaar method)? Are there any negative effects than can counteract and possibly delete the desirable ones in very wide bridges?

Would it be OK for ordinary instruments, to just set the 42 mm bridge somehow off-center, adjusting the string position and trimming the sides (by choosing a suitable blank, like the first Despiau models), and experimenting with a different soundpost length and position?

If we decide to try a new, wider bridge, would it be a good idea to start checking the instrument's sound by leaving it slightly higher, in order to have its proportions unchanged?

(my question ends...)

Thank you for your answers and suggestions,

Giovanni

(the origin of my question follows...)

We have to make new bridges for violins with odd measurements frequently. This can be some annoying task but, it is a good way to understand and learn I believe.

Some days ago, I was checking some catalogues to find wide violin bridges, and a very good paper that I read came to my mind - it is a contribution by Joseph Curtin to the XXIII VSA Convention ("Some Principles of violin setup").

In this demonstration, Mr. Curtin explains how the downward force to the violin belly changes, and how the bridge movement changes, in relation to the soundpost, bassbar and violin top, with different bridge heights, by showing its lever-like behaviour.

This time, the approach would be studying the case of a wider bridge, with the same heigth, since I am not considering changing the fingerboard projection and string height for now.

I believe that following Joseph Curtin's idea of the lever model, can be a very good start for such an analysis...

P.S. since I live in the city of Archimedes now, this can be an inspiration indeed!

[Wolfjk]

Hi Giovanni,
I gather from your post that you already know a lot about bridges, perhaps more than most of us on mastronet.
There are some points fixed on violin bridges; the distance between the strings, and the position of the foot over the bass bar. Logic would dictate that if you have a wider bridge, it needs to be higher. There is probably a mathematical formula somewhere?

[Christopher Jacoby]

It needn't be higher. We kept some wider bridges around for instruments that were built funny at the shop-- especially on a newer instrument, it can even the sound out considerably if the bassbar is set too far from the center seam. Unfortunately, I don't remember what brand stamp they were, or if they were custom!

[Brad]

Looks like Milo Stamm offers a 43 mm bridge on their WEBSITE

I think I will order a few because I have seen a fairly high percentage of violins with bass bars which are too far to the bass side.

[DGerald StephenR]

Looks like Milo Stamm offers a 43 mm bridge on their WEBSITE

I think I will order a few because I have seen a fairly high percentage of violins with bass bars which are too far to the bass side.

I am now cutting one (a Royal 43mm) to fit a widely spaced ff's and bassbar for an instrument in shop. I learned from my dealer upon ordering it that the Stamm bridges are no longer made in Germany, if that's an issue to anyone. I think he said they are made in Bulgaria now...nice bridge nonetheless.

[Giovanni Corazzol]

Thank you for your comments!

The paper by Joseph Curtin I was talking about is in the Maestronet archive, but I can't find it.
It can be reached with Google search by typing "Joseph Curtin principles violin setup".
For me, it is a very interesting and well-written introduction to the mechanics of violin bridges.

For Wolfjk: Thank you, I have read many interesting threads about bridges here on Maestronet's Pegbox. I am a virtuoso of "copy & paste"...
I couldn't find so many books about bridges and set-up at school; I have studied the Weisshaar book on restoration, and some papers by Catgut Acoustical Society, KTH and other scientific organizations, that were in the school library... And, some interesting theory and phisics also, from professor Ciro Moschella, who was the former teacher of "Lutherie Technology" at the Cremona School.

Now, my question was started by the re-reading of Curtin's paper... he made the question (more or less): "how do we decide the bridge heigth for a violin?". I want to ask: "how do we decide the bridge width?".

When I make a new bridge, for an old instrument, I always use the Weisshar method (the bassbar chapter). I never place the bridge off-center, and, I use a wider or narrower bridge blank if needed. But as Wolfjk said, some points don't change, that's why I wondered if this change was always positive, or if the benefit could be neutralized when the bridge becomes very wide compared to its heigth (heavy, heart too high etc.).

Wolfjk: mathematical formula -- as far as I know, if we treat the bridge as a rigid lever, like Joseph Curtin did in his explanation for low frequencies, we can find the momentum of the string downward forces and the resisting force of the bassbar with a graphical method; but first we need to find the direction and modulus of the 4 string forces in the bridge plane. I am sure that somebody already did these calculations... but I will try do that for me anyway, just for fun!

[nathan slobodkin]

Giovanni Your question about bridge width is a very interesting one. I was told by Rene Morel that since instruments which have wide set FF holes are usually too stiff in the center that using a wide bridge and or a wider set bassbar further increased the resistance of the instrument to the sideways rotational force delivered by the bowed string and was therefore counter productive. This discussion was regarding a Montagnana cello which he had moved the bass bar inward and then used a 90mmwide bridge instead of the 94mm which had been on it. I think that if you cannot move the bar then a slightly higher pitch and bridge might apply more leverage to get that stiff top moving and I would use an apropriately wide bridge to match the bar. I'd be very interested in hearing from some of the more experienced restorers on this subject. By the way Aubert does make deluxe bridges in both wider and narrower widths for violin as well of course as viola and cello.

[Wolfjk]

I think that if you cannot move the bar then a slightly higher pitch and bridge might apply more leverage to get that stiff top moving and I would use an apropriately wide bridge to match the bar.

It would also make better contact between the bridge feet and the top.

[nathan slobodkin]

It would also make better contact between the bridge feet and the top.

Hello Wolfjk, why would raising the neck pitch have anything to do with the fit of the bridge feet??

[Wolfjk]

Hello Wolfjk, why would raising the neck pitch have anything to do with the fit of the bridge feet??

Hi,
Simply ahigher bridge creates more downward pressure. If we're talking about a wider bridge to fit over the bassbar a normal height would give less downward pressure. Perhaps the angle of the bridge feet in relation to the outside strings has an effect?
As you said in your post, moving the bassbar inward would be a better option.