Articles
© Vincent Colletti 2016
I have always been in love with the rich sound and the classic beauty of the upright bass. Playing it is a joy. Transporting it
isn't.
I remember many nights heading to a gig with my bass strapped precariously
to the roof of my Ford Pinto. An acoustic bass guitar might fill the void between the string bass and
an electric but the ones I tried left me feeling unsatisfied.
While the upright fills a room with sound, most acoustic bass guitars are loud and thin, without
the rich even tonal response of the violin family bass. What was missing? It finally occurred to
me that the same factors that made me love the archtop guitar- the even tonal characteristics,
projection and of course the beauty of design could be applied equally to the acoustic bass guitar.
An archtop guitar could be designed for the bass frequencies. I knew that my friend Bill Moll
had designed and built an archtop bass and I was intrigued with the possibilities. I knew I wanted
as full a sound as possible without having the instrument being unwieldy. After all, someone had
to play this thing. I wanted a cutaway providing full access to a 34" scale neck. The bass had to
physically balance well as bass guitars can easily become neck heavy. With these objectives in
mind I began design.
I chose one of my guitar body styles with a 17" lower bout shifting the waist downwards-
a little more squat than other guitars. Increasing the body depth from a usual 3" to a full 3 ½ "
provided a little more lung area for lower frequencies. I used swept f holes to provide more
belly area and keeping their size and shape of a traditional design kept the sound from getting
muddy and maintained projection.
The top was arched to a higher vault than I use on a guitar and kept full. Graduation of the plates
was proportioned to a standard guitar but made thicker to support the added tension of bass
strings and keep the sound from breaking up when driven hard. For bracing I used an asymmetrical X configuration which
has the treble side located under the treble bridge foot but the bass side is swept outward from the corresponding bridge
foot. This design being inspired by classic stringed instrument construction where a violin, for example, has a sound post
on the treble side and a bass bar floating freely opposite. This bracing pattern allows the belly at the bass side to flex and
drive the top. The braces are then shaved to transfer energy throughout the top.
The head stock is similar to my 6 string designs with African Blackwood for the face plate and
Hipshot Ultralite tuners to keep the weight down and reduce the tendency to be neck heavy. The
nut is Tusq ,a manmade ivory, and the bridge is two piece adjustable carved from bird's eye
maple. I chose these materials to keep the tone well defined in the mid and upper ranges.
The tailpiece is carved ebony with Sacconi adjuster in the classic string bass style.
As I had originally envisioned the string bass as my inspiration, the fingerboard had to be
fretless. For this instrument I used a slotted fingerboard and inset black walnut into the slots as
courtesy frets. These strips were finished flush with the fingerboard surface. The neck was
constructed of a five piece laminate of bird's eye maple and black walnut stringers, reinforced
with a channel built up using graphite epoxy composite bars. Inside I installed a double acting
truss rod for additional support and adjustment. The neck profile and taper is similar to the J
bass, which many players (myself included) find to be comfortable and familiar.
I used hide glue for all structural assembly. Hide glue provides a superior joint and (in my
opinion) enhances sound transfer quality. The bindings are of a traditional archtop design. I
finished the instrument by spraying it with multiple coats of nitrocellulose lacquer.
Electronics are simple consisting of pick guard mounted volume and tone controls and a floating
humbucking pickup custom built for this instrument by wizard Kent Armstrong.
So, how did all this work pay off? Well, the sound isn't exactly that of an upright bass.
Instead it has its own resonance and quality that is unique to an archtop bass guitar, rich and full
with a character much closer to the string bass than any flat top acoustic basses I've tried.
It's playable and not at all unwieldy. And by the way, it fits easily - inside - my Honda Civic. Of
course part of the joy of lutherie is planning the next instrument!
For the inspiration to design and build this instrument I would like to thank Bob Benedetto for
his contributions to all luthiers. His work in overall construction and theory provided me with the
basis for design. Thanks to John Monteleone for his violin inspired bracing strategies. These
provide the foundation I use to reach my tonal target. I would like to thank my friend & mentor
Bill Moll for his graduation ideas and introducing me to Sacconi's "Secrets of Stradivari". Bill is
a terrific teacher as well and I had the pleasure of studying violin making and archtop guitar
construction with him on the Musical Instrument Maker's Forum (http://mimf.com). Lastly
thanks to my dear wife Anna, for putting up with all this!.
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