By Christopher Jacoby
When something goes funny with your instrument, like the response slows down, you lose volume or the ability to articulate clearly, or a string-to-string imbalance shows up, what do you do? It seems that everyone has a buddy, a stand partner, or a music teacher with a soundpost setter burning a hole in his or her pocket and sooner—rather than later—they start yanking the soundpost around.
Players and luthiers are guilty of turning to soundpost adjustment too quickly, yet nothing jeopardizes your instrument’s health like a soundpost in the wrong place. A dealer will tell you, a soundpost crack in a modern instrument can devalue it by 50 percent. So, before anyone starts nudging your soundpost, there are important things you or your luthier should check for.
Begin with the assumption that your post is in a reasonable place—inside and slightly behind the treble bridge foot. That’s where your qualified luthier put it during your last regular checkup. What you, the player, should know is that your instrument is aligned, tip to tail, with its setup centered, and that this centeredness is a key to much of the good sound you can expect from your stringed instrument.
The following ideas apply to the violin, but the concept is the same for big-case luggers who play viola, cello, and bass.
Find Your Center
There are two things a player should check before going for the soundpost. The first is to check whether your setup has been jostled off center. The violin’s setup is balanced between the bassbar and the soundpost, with the bridge feet overlapping each by roughly the same amount on either side. The neck is set in your violin straight and should be centered on the bridge between the f-holes. The tailpiece is centered on the bridge, and the saddle and endbutton are centered on a straight line from the center of your violin’s nut, down to the tailgut wrapping under your chinrest.
Assuming the neck is straight in the violin, you can check the centeredness by sighting down the top of the instrument, from nut to tailpiece. Put your eye right over the center of the scroll and peer down the fingerboard, imagining a straight line down the center. From this perspective, the end of the fingerboard should be spaced evenly between the sides of the bridge. If it’s not, then your bridge is no longer evenly supported by the bassbar and the soundpost. This will play havoc with sound when the bridge is set in motion by your playing.
If your bridge is not centered, carefully bring down the tension of your strings by de-tuning slightly. Place your violin on a soft, flat surface, and then, with both hands in full contact with the bridge and top, bring the bridge back to center. Don’t mess with this if you aren’t confident, or have had too much coffee—take it to a luthier.
Now that your bridge is centered on the fingerboard, tip your violin and look for the very end of the tailpiece. The high point—this is easier on tailpieces with a center spine, like a Hill-style, but you’ll get the gist of it—should be centered exactly between your two center strings on the blade of the bridge.
The tailpiece controls how pressure is arrayed on the various strings. If it’s too far over to one side, the strings on the opposite side are put under great pressure, and the sound of your violin becomes imbalanced. With the strings still de-tuned to make adjustment easier, move the tailgut on the saddle to the center, using your eyeball. For later reference, I mark where a tailgut on an instrument that comes to me should be with pencil on the ebony saddle.
So your setup is centered now! Tune up and try it out. Chances are that took care of your problems with the sound. If not, the second thing to check before you go for the soundpost is your string length.
Stand Up Straight!
The violin is a creature of Hertz waves. It has, in the last few hundred years, become standardized in its setup to maximize the potential of its size and shape, and to allow anyone to pick up any instrument and hit those double-stops in fifth position on the first try.
Cello and bass are less standardized—and don’t get me started on violas.
If your setup is centered, but the sound still isn’t right, you’ll want to see if your bridge is leaning. A tilted or warped bridge changes the vibrating string length from nut to bridge. If your bridge is centered between the notches of your f-holes, the distance from your bridge to the edge of your violin’s top, where the body and neck join, is called the stop length.
To check if your bridge is straight, place your violin on that flat, soft surface and bend down to see how the bridge leans in relation to the long arch of the top. If your bridge is placed correctly, the back of the bridge should be at a right angle to the flattish curve of the top plate. Bridges are carved so that the string length is correct when they’re at 90 degrees to the long arch. Daily tuning moves the blade of the bridge back and forth, and every player should get help learning to do this adjustment with facility. If you let it lean for too long, it warps, and will eventually snap, scaring the daylights out of you and possibly cracking your violin’s top.
Using both hands in full contact with the bridge and top, lean the bridge back to square. If it’s warped, it’s time to have a new one carved.
If your violin still doesn’t sound right once the bridge is straight and your setup is centered, it’s time to take it to a qualified violin repairer for a closer look. Soundposts walk out of place, and bouts open when the weather changes, and worse. Knowing a few of the basics is not the final word—but if your violin doesn’t sound its best, please don’t go right for the post.
A version of this article first appeared in the June 2014 issue of Strings.
Want more instrument and bow care? Try Strings’ Violin Owner’s Manual. We also offer a handy series of web guides: Care & Repair of Violins or Violas, Caring for Your Violin or Viola Bow, Care & Repair of Cellos, and Caring for Your Cello Bow.