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Cuckoo
for Cocobolo
Q
What is cocobolo?
Kerry
Sullivan
Medford, Massachusetts
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A
Cocobolo
(Dalbergia retusa) is a true rosewood. All true rosewoods
are Dalbergias (Indian is Dalbergia latifolia
and Brazilian, Dalbergia nigra), but not all Dalbergias
are rosewoods. It can be difficult to visually distinguish
between many trees of the genus, and sometimes a wood scientist's
analysis of the cell structure, or at least an examination
of bark and leaf samples, is needed to determine the exact
species. Common names for tropical woods can get confusing;
there are other Dalbergias and Dalbergia look-alikes
that are sometimes referred to as cocobolo, and D. retusa
is sometimes called caviuna as well as other names. However,
the D. retusa variety is the most common cocobolo.
The majority of
this wood comes from Central America and is harvested mainly
from plantations or government-controlled lands with reforestation
projects. The trees are not particularly large; mature specimens
usually range from 45 to 50 feet tall and 2 to 2 1/2 feet
in diameter. Any two trees, even those growing right next
to each other, can yield wood that varies quite a bit in color
and overall figure. I have some from Panama that's a brilliant
orange-crimson color with black streaking and some from Nicaragua
that looks remarkably like prime old-growth Brazilian—right
down to the brick-red color and black spiderwebbing.
The best cocobolo
is, in a lot of ways, as close to Brazilian as anything out
there. It's generally more stable than Brazilian but not as
stable as Indian. It is also one of the densest and heaviest
hardwoods—some of it will not float in water. Oily cocobolo
can present problems in sanding (clogging), gluing, and finishing.
Cocobolo dust can cause allergic reactions in some people
(from breathing problems to poison-ivy-like skin rashes),
which is probably one reason more luthiers aren't using it.
In a finished instrument, however, the wood no longer presents
a problem.
—Charles
Vega
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An
unfinished cocobolo body in the Froggy Bottom Guitars shop.
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Sixth
of One
Q
In
David Hamburger's lesson "Melodies in Sixths" (November 2002), he
harmonizes an E note, in the key of E, with a G#, which he calls
a sixth. But in the key of E, C# is the sixth. E to G# is an interval
of a third. Am I missing something?
Bob
Youmans
Huntsville, Alabama
A
Intervals (the
distance between two notes) and scale degrees can be easily confused.
The scale degrees for any given scale are static, but an interval
simply defines the distance between any two notes, no matter what
scale degrees they are. In the E-major scale, C# is the sixth degree,
and the interval between E and the C# above it is a sixth (regardless
of the scale). You can go either up or down to build an interval.
In the example you mention, Hamburger writes, "If you take a melody
in the key of E and play it all on the high string, you can harmonize
it by adding the note a sixth below." As you mention, building a
sixth interval with E by going up the scale will give you C#, but
going down the scale will give you G#.
—Andrew
DuBrock
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Electric
or Acoustic Amps?
Q I'd
like to retool my existing electric rig for acoustic playing. Can
I use my two 2 by 12 cabinets with either my existing Marshall head
or a new acoustic head?
Mark
Elliott
Saint Elmo, Illinois
A It's
certainly possible to use some of your electric gear to amplify
an acoustic guitar, depending on the sound you're after. As far
as I know, there aren't any acoustic amps available as heads only,
because the speakers are a big part of these amps' sound. While
electric guitar speakers tend to be designed to color the sound,
most acoustic players want something more like a hi-fi system, with
transparent, full-range sound. If you really like the idea of using
a head (the amp/preamp section of a guitar amplifier without the
speaker), you could assemble one in a rack. One example would be
something like a Rane AP 13, Pendulum SPS-1, or Presonus Acousti-Q
preamp, an effects processor, and a stereo power amp. This would
take up three or four rack spaces and, with the right kind of speakers,
could sound phenomenal. Your cabinets might work, but their lack
of high-frequency horns could make the sound too midrangey for an
acoustic. Much of this will depend on the sound you like. A friend
of mine uses a Victoria all-tube amp (a copy of a Fender Bassman)
for his Fishman-equipped Taylor, and it sounds great, although not
exactly "acoustic."
—Teja
Gerken
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Excerpted from
Acoustic Guitar magazine,
July
2003, No. 127.
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