In Depth Fiddle / Violin Acoustic Blueprinting

Our basic concept is to get the individual pieces of wood making up the instrument individually and collectively 'happy' and adjust the bass/treble/evenness/brilliance.  Many more details play into the work.  The pieces of wood possible to easily work on in a violin are the fingerboard, neck, tailpiece, ribs, linings, bass bar, top, back, and bridge. Also the F holes and F hole edges.   Keep in mind that each little step only makes a quite small difference. A possible exception is going the top plate - that can suddenly hit a sweet spot that is quite pronounced.  The description following is written for practitioners who would like to try this approach.  Keep in mind it’s just a sketch – lots more detail work can be imposed. 

 

(1) Preliminaries:


A.1. Set up the instrument well.  Get the neck and fingerboard right, the pegs working,
the post nicely fitted, and the bridge fit precisely.  Michael Darnton’s book is a great
resource for this.  http://violinmag.com/  Everything needs to be ship shape.  Keep the
instrument unstrung too allow an easier first pass on the body.
A.2 Clean up the inside edges of the F holes, primarily to get the edges smooth, without
finish ridges and other junk hanging down. This can create an audible improvement. It's
not that a lot of air moves by the edge, but that pulsing around the edge can move "noise"
into the boundary layer around the instrument's top. 

(2) Fingerboard and neck

B1. Adjust B0.  B0 is the first bending mode of the neck and body system, which can be heard by holding the violin across the lower bout and tapping the back of the scroll. http://www.catgutacoustical.org/research/articles/modetune/modechrt.html Do your fingerboard dressing before adjusting B0.  After trying various pitches, we settled on Deena Spears’ system of matching this pitch to the “Zaltone” – the pitch where the instrument lights up if sung into.  If B0 is too low, raise the pitch by scraping along side the fingerboard.  If too high, remove a little wood from the end of the fingerboard. B.2 Adjust neck.  Tap four points on the neck, two on each side just below the nut and
two below the fingerboard where the heel bend starts.  Lightly scrape the highest pitch
point.  Repeat until the four points are about the same pitch. When building or completely
dressing a neck, this general type of tapping can be attempted along the entire neck.

  1. Pre-stringing body work

C.1 Ribs & kerfing/linings.  This technique is borrowed from and expanded upon from Deena Spears book. http://www.singingwoods.org/books.html  We  work on each segment of the ribs. This can't be done completely perfectly, but does make a difference in conjunction with everything else. Spears has a system linking each rib to a block and getting that balanced out. This principle of finding the high and low spots, then getting them worked out is a basic
principle.  Six ribs, six blocks.  We use a variety of scrapers on the end of bent rods.
Adjustment usually takes very little scraping.  We individually consider the rib and the two lining pieces on each rib.  Each rib gets tapped along to find dull and lower pitched spots, first from the outside, and then lightly with a scraper inside the rib to find the center of the dull spot.  Light scraping at that location reduces or eliminates the dullness.  The linings on each side are then checked, with dull dull spots usually offset from the main one.  We repeat the process of looking for dull spots until all the substantial ones are worked out.  We work through all the ribs a couple of times.  The whole box when tapped will have a more clear sound.
C.2 Bass bar. We tap along the path of the bar to find high pitch and dull flat pitch. Scrape
the bar at the dull flat spot lightly - one can tap around with the tool to find the most dull
spot.  Very little scraping will move the spot.  Then tap again, find where the dull spot is and scrape.  The bar soon evens out.
C.3 First tone adjustments.
C.3.a Tone - The area between the treble foot of the bridge towards the fingerboard is
important. Tap around that area of the top, listening for dull spots. Very lightly scrape (or
sand) the inside of the top at that spot. A few passes and that area will be more even.
Tone will end up more open and "ah" in character.  I sometimes end up doing the entire
top this way.
C.3.b Balance - Tap the region north of the upper eye of the treble F hole. There's often a
dull spot. Scrape lightly - and I do mean lightly, this isn't really about removing any mass
to speak of - to get rid of that dull spot mostly. A little bit is OK for this part. Just don't
want a big dead zone.
C.3.c Brilliance. Wing of the treble F hole - if there's a small dead or dull spot on this
wing or back along the edge to the notch, then gently scrape under that dull spot. A
substantial dull spot indicates a lifeless top end is likely.
C.3.d Sequencing top and back. This is a bit more difficult. Tap all around the whole top,
listening for the brightest, highest pitch spot. Lightly scrape under that spot. Repeat until
the top is pretty even. The character of the response should change a lot, often rather
suddenly sounding more open. Do the same for the back.
We may lightly scrape almost anywhere in the entire interior.  We have a wide
range of scrapers on rods bent to do various things. We also have bent wire scrapers that
incorporate a guide to show exactly where the detailed scraping is to be applied.  The scraping is very slight and light, but surprisingly effective.  The above process is repeated several times, with later adjustments to some extent impacting earlier ones.
  1.  Bridge and tailpiece – before stringing up

D.1 Tailpiece.  Wood tailpieces make a difference in response and clarity.  We at the very least tap across the tailpiece just behind the holes in a band
about an inch wide, scraping until the pitch is fairly even.  We may work the sides or other areas of the tailpiece to achieve a more even response.  
D.2 Bridge.  Tap all around the upper half, scraping away irregularities.  We also check and tune a variety of other adjustments as we carve a bridge, which are more standard.  
At the close of this stage we string up the instrument loosely, adjust the post to a reasonable starting position, bring to tension, and adjust the post to the best tone (outside the scope of this description).  We also make basic adjustments as usual.
  1. Refining the adjustments.

First, we pluck and play the instrument, primarily listening to its response and nasal/open aspect of tone.  We also run up and down each string, listening for tone and volume variations, listen to harmonics to see whether they’re smoky or clear.  The harmonics are very important indicators of how things are going with the instrument.
E.1 Fingerboard/neck.  We recheck B0 and the four points indicated earlier.  We also work the fingerboard edges lightly to get an even response to tapping.  This generally takes very
little.  Then we polish in the worked areas.
E.2 Tailpiece.  We tap the tailpiece and make sure it’s about a semi-tone away from the
“Zaltone” of the box, and vibrates nicely.  Check the afterlength.  We may swap out the
tailpiece or remove material to get it working right.  There’s a bit of judgment and
intuition in this.  On a sensitive instrument, We will work along the sides of the tailpiece to
work out dull spots.  This makes a tiny difference.
E.3 Bridge.  Tap along the sides of the bridge.  Scrape any dull spots.  We like the sides of
the bridge to give an even tap.  We will also continue refining the usual bridge adjustments to
waist and so on.
E.4 Body.  Ribs, bar, sequencing the plates, as detailed above.  Putting the instrument
under tension usually shifts the response a little bit.  
E.5 Tone evaluation. We consider the bass/treble balance.  Make soundpost adjustments
and possibly scrape ala Fry.  http://dev.forum-network.org/lecture/solving-stradivarius-
secret  We gradually work brilliance into the sound.  A surprising amount of brilliance can be
worked into a decent basic instrument through bridge and F hole wing work.
E.6 Clarity and evenness.  Borrowing some techniques from Dick Hauser, we look for unevenness of volume and response along each string, adjusting through removing tiny amounts of wood from the pendulums of the bridge.  The harmonics really show
whether the string is clear and singing or a bit muddy or smoky.  This step makes a lot of
difference in the overall clarity, perceived response, and projection.  We will also go through
the string to string balance.
E.7.  At this point, any decent instrument is quite sensitive.  We work around the inside of the F holes removing uneven spots.  Tap along the line of the bass bar on the back to find
bass bar irregularities (“ears of the angels”).
  1.  Repeat.  This is important; the early adjustments will change as other adjustments are
made.  The instrument gets more clear and open, so the early adjustments can be made
more effectively.  We repeat the whole process a time or two until we are happy with it.