Different timbers for violin bridges.
A number of discussions have been about different timbers for violin construction but this question is specifically about the bridge. It does not take much material to make a bridge so have different timbers been used to make a violin bridge and did it make any difference to the sound at all ?
I was thinking about the ebony insert used under the E string on some bridges and I wondered what a whole bridge made of ebony would sound like.
Indeed, the weight and stiffness of a bridge, and their distribution via the design, have a notable effect on tone and response.
That's 3 more ways of tweaking violin sound to add to the daunting number we have already. But does anybody except the tweaker and (maybe) the player notice? The problems, of course, are that these methods are all to some degree interdependent and we're unable to make side-by-side comparisons.
There are common misconceptions about how the energy of the vibrating strings are transmitted through the bridge to the violin body. One of the more prominent is that a "sound wave" takes a path around the various cutouts of the bridge and this is the major factor for energy transmission.
Carmen, thank you. Not too technical; just right.
The bottom line is that maple works and delivers the expected sound. There's no reason to try something else, but probably everything has been tried by someone, somewhere. Still, everyone comes back to maple.
My "vibration path" was just an image. But the cutouts and thickness reduction provide flexibility as well as reducing mass and modifying the moment of inertia. I have (somewhere) a text where the writer starts with a solid bridge and cuts away first between the feet, then the "heart", then the "ears" until reaching our present design.
I recall reading that ebony inserts on bridges were used on cheap bridges. It makes sense that using a harder wood insert would avoid having the E string cutting into the softer wood.
Nowadays, a small piece of parchment is often used to protect the bridge from the E string. This is far better in all respects than the ubiquitous and ugly plastic tube thingy that usually comes with many strings - except gut of course!
..and the same at the other end can cure the whistling open E when slurring from the A-string.
Adrian, I'll bear that tip in mind to pass on to anyone I know who suffers the whistling E problem. I can't advise from personal experience because for some unknown reason I've never had a whistling open E.
I don't know if this is an "old wife's tale" but I heard that twisting the E string at least 1/2 turn when mounting it can help prevent the whistle. I have been doing that ever since I heard about it. It would appear to be the principle of the Warchal E strings and their metal A strings.
Andrew, possibly not an "old wife's tale" if the whistling is due to a torsional or twisting vibration of the string about its longitudinal axis, which could be nullified by applying a "pre-twist" to the string, as you described. If this is so, then maybe someone will have done the math and we're now seeing the result in Warchal's Amber E, and one of their high-end metal A's (Timbre?).
I had a friend named Charles Herbaut who compared materials for bridges for his project when studying violin making at the London College of Furniture with Pat Naismith (He later studied physics at Grahamstown). There were only two materials used for bridges that conducted sound at all well. One was, of course, maple. The other, boxwood I think, performed about the same. Metal didn't conduct it at all (I was his tester).
I wonder Why only boxwood and maple performed well ? Do they have similar densities ?
I think, Brian, it wouldn't just be densities - There are tensile and even shear coefficients to consider as well.
Boxwood is about 20% denser than hard maple, but it is also over 30% stiffer and crush/rupture resistant. So one might be able to carve a boxwood bridge a bit thinner than maple to get an equivalent mass distribution as maple and still have the bridge be a stable platform to support the strings.
I know it would be too much trouble and probably pointless but it would be interesting to hear the same violin/strings played with different timber bridges to hear how they sound in comparison to each other.
As long as you can get the mass, distribution, and mode frequencies in the range of good maple bridges, other woods should work as well acoustically.
Some luthiers use sycamore (acacia) bridges.
In Britain I think (from Wiki) the sycamore is a species of maple (genus acer).
"same violin/strings played with different timber bridges" - Brian, that's exactly what Charles and I did. But I think the bridges all had the same dimensions. Don has introduced another parameter that we should really have looked at. I suspect a balsa bridge would have to be impossibly thick to get the performance.