Inside-the-Shop are informative articles written by Kevin Smith, Luthier of The Violin Shop
San Diego | San Diego County | Southern California
Set Up: The Soundpost and Bridge
There is only one power that determines the course of history, just as it determines the course of every individual life: the power of man’s rational faculty- the power of ideas. If you know a man’s convictions, you can predict his actions. If you understand the dominant philosophy of a society, you can predict its course. But convictions and philosophy are matters open to man’s choice.”
What is not open to man’s choice is the law Ms. Rand used to guide her observations, just as it rules reality. The law of cause and effect.
The law of cause and effect is that bothersome one that makes you practice, take lessons, and learn your music. It’s also the one you notice when your instrument isn’t working as well as you’d like.
Maybe your viola was playing great yesterday, but today it’s a little choked and unresponsive. You have an effect, so you look for the cause. Is it an open seam? A difference in humidity? Did the bridge get bumped out of place or the soundpost shift?
Your instrument is a dynamic structure of stresses and resistance. A slight shift in the relationship within these dynamics can bring your instrument to squawking frustration as you try to weave yourself into a Hayden quartet, or ecstasy and ease at your fingertips, playing a Bartok cadenza.
In message #1 we talked about how to evaluate sound. How understanding and developing it as a skill gives you a well-rounded ability to judge any instrument. But it’s for much more than the occasional effort of finding and buying the violin of your dreams.
As your understanding and evaluations of sound develop into a skill, your ability to manipulate and control it under your bow will set you apart from the average player. It will also sensitize you to the dynamic flux of your instrument. And the effect its’ setup has on how it responds to your commands in every category: response, evenness, and voice.
There are several categories of setup we could consider. We’ll cover different areas of setup in future messages. But for today we’ll stick to the easily adjusted parts of acoustical setup.
Namely the soundpost and bridge.
The soundpost is so much more than just a post inside your instrument supporting the pressure on the top (to see it simply look through the treble side f-hole). Just as the bridge goes far beyond the obvious roll of holding the strings up. Their placement is crucial to good sound. As well as how they fit, how tight the soundpost (long or short), various thicknesses, and different cuts made on the bridge.
Since the post and bridge are movable they are fit to accommodate the location of a couple of semi permanent fixtures. The bass bar and the neck.
The bass bar is a fitted piece of spruce inside the top. It runs lengthwise, under the bass side foot of the bridge on a violin, viola, cello, or bass. I won’t get into the acoustical properties here. For now it’s enough to know that being glued on the inside, the bass bar is an anchor position for setup. The neck falls into the same anchoring category.
And together they determine where the post and bridge will be fit, and what cuts need to be done so the strings line up without compromising the acoustical alignment.
If your violinmaker has done a good job, your instrument will effectively be brought to its’ greatest potential. And this is how you want to know your instrument. At it’s best. That way when the post or bridge moves and is out of adjustment, you’ll know.
For example, if during intermission or a break at rehearsal, someone were to accidentally bump your instrument, knocking it out of adjustment, the first thing to look at would be the bridge.
If before hand you’ve looked closely and noted where it’s located, memorizing a strong grain it’s lined up on, or an odd mark, you would look to see if it’s different. Often times you can see if it’s moved because of the rosin dust that’s missing where the foot was (even though it would be better to wipe your instrument down as a habit before you set it down).
If you see it’s moved, take it to someone who knows what they are doing and have it put back. A user-friendly violin-maker will be glad to show you how to do it for the future.
If it hasn’t moved, check for openings (message #3). If you still don’t find anything you should get into your Luthier and have your soundpost checked and adjusted. Without the right gages and tools it’s almost impossible to do. Not to mention the subtlety of experience.
But all the categories of sound can be affected. And they can all be manipulated by adjusting the placement of the post and bridge.
Even though there are some rules of thumb for adjusting soundposts, each instrument is a little different. And because your violin, viola or cello can be damaged by less skilled Luthiers, it’s wise to find someone who has been put through the tasks of learning from pedigreed professionals.
Because there again, it’s cause and effect. The more skilled the people you work with, the more value your instrument will retain, and the more potential you’ll realize from it.
SADDLE: The saddle is the small piece of ebony set into the edge of the top plate just underneath the tailpiece (where the strings hook in below the bridge). The saddle is tough enough to withstand the wear and tear of the “tailgut” that goes across it and hooks onto the endbutton.
As far as the adjustable set up is concerned, the saddle can be cut lower or replaced with a higher one in order to fine tune the set up and optimize the sound.