Your Bass Playing The Way You Want
Bridge and Nut
bridge and nut serve two functions: holding the strings in
proper position for playing the bass, and transferring the
tonal vibrations of the strings to the instruments sound
chamber. Both bridge and nut can have a profound effect on
a bass playability, depending on the height at which
they hold each string, and the spacing between the strings.
They also play an important role in keeping the strings centered
over the fingerboard.
Nut: Generally made of ebony, with the grain at 90 degrees
to the grain of the fingerboard, the nut is the piece located
at the upper end of the fingerboard, which is grooved to guide
the strings into the pegbox. Providing the fingerboard has
been properly dressed, a bass plays and sounds best when the
nut grooves are cut quite low. I like to be able to just slide
a business card under each string where it meets the nut;
the card should encounter a bit of resistance. When the nut
grooves are too high, a bass will lose sustain and liveliness
of tone, and be difficult to finger in the lower positions.
When cut too low, a buzz or rattle will occur when the open
string is played. A word of caution here: It is common to
encounter a bass fingerboard that has been slightly rolled
off downward at the nut, as a result of incorrect planing
and/or polishing technique. This needs to be checked for with
a small straightedge before lowering the nut grooves, otherwise
a nasty buzz will be the likely result. Of course the fingerboard
dressing ought to be properly re-done, but this is not always
an immediate option.
spacing of the strings at the nut is commonly between 9 and
11 mm, measured from string center-to-center. I prefer 10mm,
and I like to have about the same amount of fingerboard revealed
to the edge of both the E and G strings.
nut grooves should be just slightly wider than the string,
and cut about ½ the strings diameter down into
the nut wood. The grooves should be cut with a slight downward
angle (toward the pegbox) where the groove meets the fingerboard.
From there, each string groove should gently slope downward
toward its tuner shaft. The grooves need to be lubricated
with graphite, ideally from a soft pencil.
have heard both classical and jazz players express serious
surprise at the amount of playability improvement that a simple
nut adjustment can provide. Improvement in tone is an occasional
Bridge: Made of quarter-sawn maple, the bass bridge holds
the strings at the proper height from the body, and is arched
to allow for effective bowing. Several important decisions
must be made before selecting or making a bridge blank to
be used on a specific bass: 1) How wide a bridge does this
bass need? 2) Do I want adjusters, and if so, what type? 3)
Do I wish to alter the string length? 4) Do I wish to alter
the tone, and if so, in what way?
width of the bridge blank to be used is determined mainly
by two factors; the distance between the upper eyes of the
f-holes, and the position of the bass bar under the bridge
when the bridge is centered on the top table. It is considered
desirable to use a bridge not much wider than the distance
between the upper eyes of the f-holes. The reason is that
a wider bridge exerts pressure outside the area of the top
table which contains long grains of wood to transfer the pressure.
As a result, the top may sag around the f-holes from a bridge
that is too wide. The bridge should sit with its E-side leg
partially over the bass bar. The position of the bass bar
needs to be mapped out on the top table with a grease pencil
in the area of the bridge, and a blank chosen which sits nicely
over the bass bar. Sometimes a bridge must be chosen which
is slightly wider than the distance between the upper eyes
of the f-holes, due to the position of the bass bar. And sometimes
a bridge must be chosen that is considerably narrower. In
general, a wider bridge promotes a deeper sound, and a narrower
one, a more focused sound. However, the position of the bridge
over the bass bar is most important; a bridge that is too
wide can actually sound less deep than a narrower one, if
the bridge leg sits farther out than the bass bar.
adjusters are pretty much a necessity if the bass lives in
a temperate environment. Adjusters allow the player to adapt
his bass to dryer and wetter climatic conditions, the condition
of the player's chops, and also allow small bridge crown adjustments
without bridge replacement. There are many opinions as to
which type of adjuster is best; there are aluminum, maple,
ebony, carbon fiber, polymer and titanium (and possibly others)
to choose from these days. Each has its advocates, yet the
difference in tone and response between them is minor. I believe
that a good material for bridge adjusters combines fairly
high density with light weight, and for that reason I usually
use aluminum. It makes sense to me that the adjuster should
be as close to retracted as possible, with just enough play
to allow for seasonal repositioning. When the threaded adjuster
shafts are quite exposed, there is less thread inside the
bridge making tonal and mechanical contact, and I think the
tone suffers (stripping-out is also a danger). I don't think
there is a tonal difference between bridges with the adjusters
installed threads-up and those installed threads-down, though
I prefer the latter (it just looks better to my eye). There
is still controversy over which sounds "better";
a solid bridge, or one with adjusters. I have cut many hundreds
of bass bridges, and I prefer the sound of a bridge with adjusters.
I think the added flexibility allows the feet to nestle more
closely into the top table, and I nearly always feel that
I hear an improvement in clarity when I install adjusters
in a solid bridge. I'm sure I'll get letters about that one.
slight amount of string-length adjustment can be achieved
by the positioning the bridge and by adjusting the angle at
which the feet are cut. And a slight bit of tonal adjustment
can be achieved by choosing a bridge with wider-grained, softer
wood, vs. narrower-grained, harder wood. In general, the harder
wood will provide a slightly brighter sound.
two most important things a bass player can do to keep his
bass playing and sounding its best are to keep the bridge
properly positioned, and keep it free of rosin and dirt. Know
your string length, and the proper position of your bridge
as it was fit by the luthier, and check it regularly. And
keep the junk off it, as an undulating bass bridge transfers
its energy best without added mass.
Please send your questions to: ArnoldS@aesbass.com.
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