Page V-113
(Modified 11/2020)

Hematite Burnishing Violin Plates...

 Web Host: David Langsather {Violin Maker, Researcher.... Salem, Oregon, USA}

...As the result of two years of Violin Timber {that is what makes for a superior and pleasing violin sound or voice.} research focus One of the apparently important features to meet this goal is to produce an instrument that increases the loudness of the lower overtones and decreases the upper overtones, especially over 2300 HZ.
   Our ears are much more sensitive to higher pitch sounds so that for us to enjoy a fuller musical experience; we need to hear music played on an instrument that has this attribute.
   Each of the above three items do just this.
  We analyzed the sounds produced by exceptional instruments of these two foremost violin makers with modern sound analyzer software and excellent audio recordings; selecting passages where only the violin was playing a single note. As you will see later on in this discussion.
...First let us look at Hematite Burnishing technique and see how this was done 'back in the day.'
..Kahlil Gibran, a professional guilder, and instrument maker, states that a piece of Hematite was found in Stradivai's work shop possessions. He believes this explains the burnished striations characteristic of his 18th century violins. I have discovered that there is a desired acoustical characteristic produced in reducing the strength of upper overtones in played instruments constructed this way....
..Low angle light reveals the surface striation left in the wood surface; even this maple surface. I suspect that only the outside surfaces were Hematitie burnished.
..My research suggests an increased positive acoustical effect with also burnishing the inside of the plates as well. Whether this is overdoing the effect is still under investigation.... David Langsather
..The technique is to press down on the wood grain, carefully supporting on back side, and stroke in one direction, and then moving over one grain and returning. When completely done, repeat for second time. Research has show that twice gives the optimal effect.
..My research shows that when this Hematite Burnishing step is completed (two times only); that another step is equally helpful for improving violin sound and overtone control...
..That is, Dutch Rush (final sanding), the old traditional wood finishing method widely used until 'and paper' was invented.
..Little did the makers who switched to the 'modern' sand paper, realize that they were trading in acoustical advantage for construction convenience ! {Our violin sound being the loser!}
..Again: two applications of Dutch Rush sanding has proved the optimal number of time for superior violin timbre results.
..Secondly, Dutch Rush sanding of finished surfaces, inside and out (excepting glue joint surfaces) gives a similarly improved acoustical result of lowering the upper overtones. Twice is also found to be the optimal number of applications:
..Sand along the grain of the wood covering all wood areas evenly; inside and out; and then repeat the second time. {bass bar surface too}
..Then you are done for the inside wood preparation.
..For the outside, once assembled; you are ready to apply Fuller's Earth varnish ground and top coats (two each) [with coloring added] and your finish is done!