Purpose of the Bass Bar?
I am just curious, what is the purpose of the bass bar?
I was reading about violin as an instrument (history, construction, etc). While most components in a violin was well explained, I only find info on how to fit but not what it is for.
I suspect it has to do with tone production, but based on what I read about, the violin mechanics is we draw the bow over the string, the rosin in the bow grabs the string and create a vibration. The vibration triggers down to the bridge then to the top, the sound post then to the back. It doesn't seem the bass bar inside is doing anything?
According to the A Dictionary of Music and Musicians by George Grove:
Many thanks for both of you! Now I learn more!
Most modern strings give a total tension between 45 and 55 lbf, a lot less than the 80 stated and also less than Tartini’s claim of 63 lbf, so increased tension is not the reason for changes in bass bar design.
In addition to the structural support due to string force, there is a another function of the bass bar. When making a violin, you strive to create a front plate with a full and strong tap ring tone, and at a specific frequency, prior to cutting in the ff holes. When you cut the ff holes, the plate goes from a acceptable ring, to a dull thud. The bass bar, assuming installed and tuned properly, restores the ring tone of the free plate. This is not something that is apparent unless you have spent significant time creating a beautiful plate, only to be disappointed when you cut in the ff's! No problem, once the bass bar is in and proper, all returns to good!
All other things being equal, there's far less tension in a synthetic string than in a steel string. And also nylon would seem to have less tension than gut, too.
I recently restored as a baroque set up violin, an original circa 1800 Hopf stamped violin that had no original bass bar, and clearly never had one. The wood was quite thick in the bass bar region, 4-5mm. Checking with an expert it was decided to string it up just as it was built, with no bass bar. The result a not very loud violin with good tone but a little bit weak G string, so it would seem that the bass bar does indeed help the bass response and possibly the volume.
One of the things ignored so far in all this discussion (and misstated by Beament in his book) is that the "tension" in the strings is translated to a downward "force" vector on the bridge (not "tension") and since the angle of fingerboards and thus the height of bridges and the force vector (apparently called "pressure" by many) through the bridge into the violin top was increased because of that after the Baroque period, that is another reason for subsequent changes to the bass bar.
Actually modern scholarships refutes the idea that average baroque tension and downward force were any less than modern set up, the angle over the bridge has remained pretty much the same, and the tension of gut strings in the 1700s is often thought to be higher than modern strings if not equal.
Certainly seems to be some very interesting "reverse engineering" research going on re. this subject. Thanks, Lyndon, for that input.
I am reluctant to believe some of the figures in that Grove Dictionary quote. A violin strung to 80 lb tension - really? I would not want to play or even handle such a violin, or be anywhere near it for that matter!
Those figures for tension aren't high, Trevor.
If the linked graph for tensions of many string sets is to believe, the total tension of a set of modern violin strings ranges from 48 to 57 lbs. The actual downward force on the bridge will be considerably less (a simple trigonometric calculation based on the string bend angle at the bridge).
One mustn't forget the more direct tension loading on the tailpiece cord and in particular the end button. I've known end buttons fail in orchestras, and it even happened with a professional solo violist in a concerto once.
I think the bass bar is less for structural support and more for keeping any undesirable nodes from forming...
The bass bar serves several purposes.