mandovoodoo
acoustic blueprinting
violin/fiddle
mandolin
guitar


acous•tic blue•print•ing: The process of refining an instrument for most efficient
operation with minimal noise, sweetest tone, and most open feel.


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VIOLIN BLUEPRINTING

The 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.  A few
more details play into the work.  The pieces of wood possible to easily work on in a violin
are the fingerboard, 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's 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.

A. 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.

B.  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.  I follow 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.

C. Pre-stringing body work

C.1 Ribs & kerfing/linings. I learned this from reading Deena Spears book. http://www.
singingwoods.org/books.html I 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.  I use a variety of scrapers on the end of bent rods.
Usually takes very little scraping.  I’ll do the ribs and the two lining pieces on each rib.  I'll
tap along the rib to find the dull lower pitched spots. I'll lightly tap with a scraper inside
the rib until I find the center of the dull spot, then scrape that a little bit, and test the
linings adjacent to that spot. Usually they'll be minor dull spots on linings offset from the
main one. I'll tap again and find the next spot that's not happy.  And move on to the other
side.  Eventually all this will work out to have no big dead spots around the ribs, just light
variations.  The whole box when tapped will have a more clear sound.

C.2 Bass bar. This will get refined, of course, once there's pressure on the top. Same
basic principle. Tap along the path of the bar to find high pitch and dull flat pitch. Scrape
the bar at the dull flat spot lightly - can tap around with the tool to find the most dull
spot.  Doesn't take much. Then tap again, find where the dull spot is and scrape.  Pretty
soon the bar is much more even.

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.

You'll note that I may lightly scrape almost anywhere in the entire interior. I have a wide
range of scrapers on rods bent to do various things. I also have a bent wire scraper that
incorporates a guide to show exactly where I'm scraping. After I go through the
instrument this way, I start over on the ribs and run through the whole sequence again.
Sometimes things change a bit.  Now string up the instrument, see what you're moving
towards.

D.  Bridge and tailpiece – before stringing up

D.1 Tailpiece.  Wood tailpieces I’ll tap across the tailpiece just behind the holes in a band
about an inch wide, scraping until the pitch is fairly even.  

D.2 Bridge.  Tap all around the upper half, scraping away irregularities.

Then 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).  Also, make basic bridge adjustments.

E. Refining the adjustments.

I’m not going through the basic bridge and soundpost work.  I’ll listen to the instrument.  
Bowing, mainly listen to response and nasal/open aspect of tone.  Run my fingers up the
strings 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.  I check the same things as above.  I also tap along the edges of
the board and lightly scrape to get even response to tapping.  This generally takes very
little, and I’ll polish in the work carefully.  I’ll also polish in anything I do on the neck.

E.2 Tailpiece.  I 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.  I 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, I’ll work along the sides of the tailpiece to
work out dull spots.  This many make a tiny difference.

E.3 Bridge.  Tap along the sides of the bridge.  Scrape any dull spots.  I like the sides of
the bridge to give an even tap.  I’ll 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. Will consider the bass/treble balance.  Make soundpost adjustments
and possibly scrape ala Fry.  http://dev.forum-network.org/lecture/solving-stradivarius-
secret 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 (whose post I
can’t find), I look for unevenness of volume and response along each string.  I’ll find the
appropriate spot on the pendulums of the bridge and remove a tiny bit of wood.  The
easiest and quickest place is at the tips of the pendulums.  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.  I’ll also go through
the string to string balance along the way.  There are bridge and soundpost work that
helps this out.

E.7.  At this point, the instrument is pretty sensitive.  I’ll go around the inside of the F
holes working out uneven spots.  Tap along the line of the bass bar on the back to find
bass bar irregularities.

F.  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.  So I’ll repeat the whole process a time or two until I’m happy with it.  

gianna, inc. – friendsville, tennessee, usa –  skype stephen.perry.esq – mail@mandovoodoo.com – 866 886 6546