From Jerald Archer
Posted November 5, 2008 at 06:15 AM
I have a few questions about the structural factors of bridges that some of the luthiers on the forum could help me with:
What qualities make a good bridge?
How does the amount of wood affect the overall sound?
What is a proper age for a bridge?
Baroque vs. modern bridges?
How do the openings (eyes) and their location affect the sound and why are they there?
Thanks for any help.
I am not a luthier, so you don't want me to make a bridge for you, but here are some things that might be useful to you.
1) What qualities make a good bridge?
This is a VERY complicated question, but here are some things that might help you in your search.
First of all on the practical side, let's start with some basic things that a bridge does. It holds the strings in a playable position. A bridge must be the right height above the strings and have the proper curvature. Unless these two characteristics are correct, the bridge will not be playable. People can argue over what they think is "proper", but ultimately the right height and curvature are characteristics that will affect how the violins plays and feels under a musician's hands. Simply put, if the bridge and curvature are not within an acceptable range, the instrument will not be playable. The last very basic characteristic is that the feet need to fit the curvature of your violin as closely as possible to assure clean transfer of vibration from the bridge to the violin and to prevent damage to the surface of the instrument.
Now you ask some other questions in the areas of wood, shape, style which I will address more generally.
At this point we are past the very basic characteristics and now we are getting more into the more complicated areas.
For starters, a violin bridge serves two purposes simultaneously. It is both the primary transmitter of vibrations from the strings to the violin and a filter between the strings and the violin. With that in mind, all of the things that you have mentioned (and a few more) affect the sound that comes from a violin. Let's isolate a few things and discuss them for starters.
You ask about the amount of wood and how it affects the overall sound. Now that is a good question and ulitmately it's a very complicated answer, but for starters let start with mass. The more wood that you have in a bridge - generally speaking - the more mass you have. Generally speaking the higher the mass, the lower the frequency of the bridge. If you have a bridge that is way too thick, then you will get too much filtering and dampening of the vibration of the strings. To most people that sound will be tend to be muted and lack focus.
If you do the opposite and have a bridge that is too thin, you will get the opposite effect in that the sound will be too bright and shrill. There is also one other significant downside of a bridge that is too thin, and that is that if the bridge is WAY too thin, you are much more likely to have a catastrophic structural failure which will render the instrument (and possibly the musician) completely unfunctional. While rare, this has been known to happen, and bridge structural failure is almost always considered a bad thing.
Now, one thing you have to realize is that pieces of wood are significantly different. People have mentioned things like age but really what we are talking about here is a strength to weight ratio. Simply put, most of the time a violin maker is looking for a piece of wood that is very strong and very light. A bridge blank that is strong and light gives a maker the most options because if you need to, you can make it thinner AND the basic frequency of the bridge will be higher (because lighter stronger materiels vibrate at a higher frequency - all other things being equal). So the basic piece of wood that is chosen to make the bridge has a strong influence on the overall tone characteristics of the bridge. You can be a great chef, but it's hard to make beef out of chicken. So if you want to make a good bridge, you have to start with a good piece of wood.
Old wood tends to be a little bit lighter because it has had more time to dry, but also remember that wood from trees of the same variety can be very different due to growing conditions. Let's put it this way, bad old wood might be better than bad new wood, but good wood (new or old) is always better than bad wood. What a violin maker is looking for is options in a bridge blank and better wood gives the maker more options in addition to starting with a better basic sound.
Now as far as the goofy lookin holes in the bridge. They are there for several reasons. One is that they make the bridge lighter and how you make those holes (as well has how you make the overall shape of the bridge) can have a significant effect on the sound. We are really talking about modifying the filtering of the vibrations and simply put, different shapes will transmit or filter different vibrations. This is where the knowledge and skill of your luthier really comes in here. By changing the holes holes in the bridge, the luthier changes what is transmitted to the violin and that can have a dramatic difference in the sound. What look like VERY small changes in hole size and shape can have large changes in the sound.
In truth, the making of an excellent bridge for an instrument is a microcosm of making a violin. You have so many variables that affect the outcome, and once you start crafting a bridge for a particular instrument and a particular musician, it's a very difficult task. Keep in mind that you can only take away materiel from a bridge and you cannot undo any change that you make to it.
As far as baroque vs modern violin bridges, I don't know anything about baroque bridges so I can't comment on them.
Hope this helps you.
I suggest you take a look at www.violinbridges.co.uk/index.php They have not only a great array of bridges, but a reference section that probably will address most of your questions.
Thank you both for some other insights on bridge qualities. I have been cutting my own bridges, mostly due to financial necessity, for about 15 years, and have discovered many variables can be involved. The marriage of bridge and violin , not to mention the the sound post, is one that seems to require a great deal of trial and error. In my practice, I will cut several bridges of various grades and install it with a very precise fit. After it is allowed to settle for a few days, I make a good clean recording of the sound and compare it with other recordings of other fittings, and their shape qualities. It becomes an experiment in acoustics after that, and I have been able to make a bad violin sound good, using this method of comparison. Though I must add, I only do this home surgery on less expensive fiddles, and would never think of perfoming it on a very fine violin. A qualified luthier is capable of better work that I could ever be, although there have been times when they have dissatisfied me as to the tone quality (and sometimes work quality) I was getting, compared to one of my own work. I learned the art from them and a good amount of reading on the subjects of violin repair, in general.
Here is a strange story: Believe it or not, one of my many experiments led me to the conclusion that if the pores are filled in the worst of bridge material, it not only strengthens the bridge overall for a very long period of time, but improves the tone, equalizing the highs and lows, respectively. I do this by completely submerging the newly cut bridge in india ink for about 1 minute and slowly drying it over a candle flame. One can see the bridge "bleed" and dry as this is done. I learned this strange technique from an old country fiddler, after I asked why his bridge was black. I thought it was made of ebony! He claimed the bridge was on the instrument for 20 years, and it was hard in texture straight as an arrow! The sound produced from the instrument he played was a mixture of both rich and sweet. I have yet to meet a luthier who has heard of this technique, most claim it would only be decorative in nature, and I seem to be the only violinist who uses it . It works for me, but I cannot explain the physics, although the recordings are my only concrete analysis of the phenomonon. I still use the technique today on some of my violins and a comparable difference can be heard. Stranger things have happened, I'm sure.
so far, I have found untreated, best woods are better than treated, poor woods. also, I have found the inherent sound of the violin can be optimised by a bridge, but not improved (a bridge alone will not give you a Strad). also, given equal woods, the shape of the bridge can have dramatic effects. finally, trial and error has been the only method available to me for determining the final bridge shape and soundpost position. ahhh, the intrigue!
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