In the past five years, I’ve had the pleasure of tuning the plates andputting bass bars in many (100+) violins of varying qualities. Some havebeen very poor violins with soft, almost spongy wood, while others havebeen real quality fiddles. I’ve found that the softer, more flexible platesrequire a slightly more substantial bar, but only in relation to the entireplate. The bar will not correct for bad wood, arching, or graduations.It will only allow the maker to maximize the intrinsic qualities of theplate.

It seems that in the best violin tops with split, well-chosen wood (lightin weight, strong and well graduated and tuned), the bass bar does notneed to be more than 270 mm in length. Other suggested dimensions are 10to 12 mm in height under the bridge, 5.5 mm wide at the bridge and lowerbouts and 5.0 mm wide towards the upper bouts, and 3 mm tall at the ends.The shape of the bar seems to follow the inverse of the exterior arching.After hearing Tom Croen and Bill Atwood talk at the Albuquerque, NM VSAconvention, a slight 1.5mm spring is gradually placed into the bar fromthe bridge towards the ends.

In my opinion, the bass bar serves several purposes. It allows the makerto retune the plate to the pre "F" Hole resonance that was destroyed bycutting the "F" Holes. It allows the maker about 5 to 10% leeway in controllingthe three primary eigenmodes. It allows the lower frequency pumping actionof the bridge to be evenly transmitted to the upper and lower bouts. Itoffers to the bridge a vibration conduit for the middle and upper frequenciesto be evenly transmitted to the upper and lower bouts of the top (veryminor if any assistance at all).

My bars are placed at 90 degree angles to the top which means they slightlytilt towards the middle of the plate when viewed through the end pin hole.My bars also taper from the bottom (where the bar is glued to the plate)to the top.

The wood for the bar should be perfectly split having no run out. Ihand split the wood in the traditional way for the perfect quarter, thensplit it again in the slab direction to make certain it runs true in thisdirection also. I have been lucky enough to find a very small quantityof wonderful spruce that splits across the grain (quarter) almost in theperfect shape of the inside arching of average violins. The wood shouldbe light in weight and very strong. I prefer spruce that has a fine wintergrowth and a medium to fine summer growth so that the 5.5 mm wide bar hasabout 6 to 8 winter rings.

With all of the above said, let’s take a look at the average bass bar.It is TOO BIG! Like Bill Fulton, who puts in smaller bass bars becauseof his very light weight and very strong tops, I’ve found that the qualityof the top plate predetermines the shape of the bar. The same bass bardimensions will not work for all fiddles!

The bass bar has a greater chance of making a good top sound bad thanit does making a bad top sound good. In other words, it is the combinationof wood, modeling, arching, "F" Hole design, placement, graduations, ground,and finally varnish that determines the ultimate value of the plate, notthe bass bar.

Once again . . . The bass bar only allows the maker to restore and retunethe plate to the original resonance before the "F" holes were cut. A well-designed,cut, and tuned bass bar can only improve the top eigenmodes and resonancea small amount (I believe no more than 5 to 10%). Conversely, a poorlydesigned, cut and tuned bass bar can degrade the eigenmodes and resonancegreatly.

Perhaps before new designs, materials, and methods are employed in newstyled or experimental bass bars, the old tried and true methods shouldbe tried, BUT…. The bar should be done well in the traditional manner first.

Comments, ideas, and suggestions from anyone in the group are solicitedand welcomed.