ACOUSTIC SOUNDBOARD
Where Tone Begins
What I love about guitars is that they are not
only magnificent works of art—they are, like
a paintbrush is to an artist, the practical and
creative tools that musicians use. And even
though the art of inlay and marquetry has risen
to an unprecedented level, the decoration
on a guitar is just that—decoration. It’s pretty
and it has value, but I haven’t come across any
evidence that mother of pearl or abalone shell
has any better tonal properties than a pebble,
or a piece of plastic for that matter.
Wood is where the tone is! I’ve heard every
story in the book about the secrets of tone, from
soaking spruce in shrimp shell brine to blasting
your guitar case with your stereo speakers! My
favorite story is about the harvesting of spruce in
Stradivari’s time. The obscure legend has it that
high-elevation alpine spruce trees were necessarily cut in the late winter prior to the thaw.
The violin makers would wait at the base of the
mountain and listen as the spruce logs were cut
and sent down the mountain in snow troughs.
The logs that made a distinct whistling sound
as they flew down the mountain were the ones
chosen for the best violins. Poppycock, you say?
Most likely, but it makes a fun story.
Back in the 1980s, some colleagues and I were
struggling with a 7/8-size baby Dreadnought
model we had concocted. The first prototype
was producing an odd overtone, what violin
people call a wolf tone. One of the master
luthiers was taking a walk through our area
and overheard our discussion. He asked about
the bracing pattern, and was quickly able to
solve the problem for us. By angling the tone
bars a bit more and adding a couple small
braces (you should never have a space three
inches square or larger unsupported by a
brace), the unpleasant wolf tone disappeared.
DICK BOAK
Bookmatched tops
(we call it pound cake) with tight, straight, even
grain and lots of lace (medullary rays), devoid of
runout on the center seam. I used to think that
this selection process was a bunch of hoity-toity
voodoo, but acknowledging that there might
be some validity, I learned to hoist each top up
to my ear and tap, listening carefully to both
the pitch and the intensity. Gradually, I began
to differentiate the tap tones of the various species. Sitka spruce seemed to have a low, boomy
rumble, while Adirondack red spruce had a
significantly higher pitched ping. Engelmann and
Italian alpine spruces seemed to fall in between.
Now my question was, what relationship could
there be between these tapped notes and a
finished guitar? After all, there are spectacular
guitars made out of all of these spruces.
Drum heads that are stretched tightly produce
a higher pitch and a resulting louder projected
sound, and guitars are, after all, drums with
necks and strings attached. So, of late when I
look at wood, I look for a higher pitched tap
tone. Beyond that, there are so many other
variables working together in an acoustic guitar: the size and shape, of course; the infinite
variety of bracing configurations; the reflectivity of the sides and back; the degree of arcing
on the back; and the mass of the neck, just to
name a few. Because of the cumulative impact
of these many influences, I prefer to remain
an eternal student, in awe of the mysteries of
tone—as opposed to an arrogant fool.
Through the years, I’ve been asked to select
wood for hundreds of special guitars. Of course,
I would always pick pretty quarter-sawn spruce
I am, however, personally enthralled by two
opposing properties of guitars: lightness versus heaviness. Every now and then, I pick up
a guitar with mahogany back and sides that is
so light in weight, I am immediately startled.
Playing such a guitar is almost always a delight.
The tone can be described as brilliant, glassine,
breathy and crystalline. Conversely, I’ll pick up
a guitar with rosewood back and sides, and I’m
often struck by the heavier weight of this denser wood. Strumming a chord on these guitars
Tapping on the factory floor
can unleash a depth and resonance that seems
to emanate from behind your spine. I used to
play an autoharp, and I always loved to place
it on the dining room table and strum it. The
whole room would resound. It was the absorption of sound conveyed through the extra mass
of wood, reverberating and echoing, like singing in the shower! That’s the rosewood sound:
dark, warm, thick and full.
So, I think these two opposing tonalities (like the
Treble and Bass knobs on your sound system)
can be manipulated by the instrument maker’s
understanding of lightness or absorption, to
yield a wide variation of desirable tone. That
only scratches the surface of my fascination with
guitars. Each one is a distinct individual, just like
the people who make and play them.
dick boak
Prior to, and during the course of, his 33-year career with
C. F. Martin & Co., dick boak (small letters!) has been a
vagabond, communal architect, illustrator, art teacher,
geodesic dome builder, lathe turner, luthier, draftsman,
poet, guitarist, wood expert, author, desktop publisher,
singer/songwriter, apple computer geek, archivist and
publisher. By the time you finish reading this paragraph,
he will most likely have morphed into something else.
Raw Sitka
