Optimal tuning of classical guitar
part 1: tuning strings
by Dr Tom Chalko
Have you noticed that your guitar is "out of
tune" at some higher fingerboard positions, even if all strings
seem in tune in lower positions?
The single most important property of a musical
instrument is an ability to tune it.
If an instrument cannot be tuned perfectly, it becomes an expensive
piece of woodwork that does not deserve to be called "musical
My approach to this problem in the past was to aim for a "tuning
compromise" so that all notes on the fingerboard were "equally
Eventually I decided to modify my guitar to achieve perfect tempered
scale tuning by means of optimizing the bridge support point for
each string individually.
In theory, the XII fret should be exactly in the middle of the
string. However, when the string is pushed towards the fingerboard,
the tension in the string increases and this (of course) changes
This change of pitch is different for each string
in a set due to differences in string tensile stifnesses. G3 string
is typically the stiffest and produces the largest pitch changes.
My method of finding the optimal string support point on the guitar
bridge relies on matching the pitch of the 1-st octave (half-string)
harmonic with the pitch of the string when pressed down in XII
If they are matched, and fingerboard is of a reasonable quality,
all notes played on this string anywhere on the fingerboard are
tuned in the best way possible along the tempered scale.
Optimal bridge support point can be different not only for each
string in a set, but also can depend on a choice of strings and
their tension ratings.
Fig. 1 depicts an "adjustable" solution.
It implements 6 tiny ebony blocks, each with a slot for a string.
To prevent these tiny blocks from moving around on a slipery surface
of the bridge I equipped the bottom of each block with a layer
of 1200 grit sandpaper, by glueing the sandpaper with an epoxy
As you can see in the Fig 1. every string is supported at a different
length and none of the supports are where the instrument maker
(Rudolf Klier of Erlbach, Saxony, Germany) designed them in 1975...
For the first time since I acquired the guitar from Rudolf Kier
in 1975 I was able to tune it perfectly and confirm the tuning
precision with a spectrum analyzer.
I was greatly surprised how much this perfect tuning increased
my joy of playing. All octaves and cords became perfectly tuned,
up to XIX position...
After playing with the adjustable bridge tuning
system shown in Fig 1. for a while I noticed that positions of
bridge blocks changed very little and decided to make a permanent
bridge bone, depicted in Fig 2.
Fig.1 Adjustable individual bridge supports for
each string enable perfect tuning of a classical guitar along
a tempered scaleFig
2. Fixed bridge bone is more than twice as thick as usual to facilitate
tempered scale tuning and maximizes the stiffness of strings-to-guitar-top
connection by increasing the surface area of string support.
Precisely fitted one-piece bridge bone provides maximally stiff
connection between strings and guitar top to improve transmission
of vibrations from string to the guitar top. This strategy improves
guitar sound quality and volume.
The most noticeable effect of perfect tuning
was the improvement in the ability of guitar to sustain sound.
The theory of this effect is quite simple: when notes in chords
are in tune, harmonics from plucked strings resonate with harmonics
on other strings, maximizing the sound energy and sound amplification.
In contrast, when notes in cords are out-of-perfect-tune,
even very little, the opposite effect takes place: harmonics from
different strings distrurb (interfere with) one another, reducing
the sound energy projected by guitar.
The only shortcoming of custom-fitted bridge
bone is that it needs to be precisely manufactured using specially
designed machine tools followed by laborious manual adjustments.
But the result is really worth the effort.
I have implemented the fixed bridge bone solution to 2 guitars
that I own and results are quite remarkable. Guitars came to life...
Please contact me
if you are interested in maximizing the performance of your guitar.
Another technique that I use to optimize guitar
sound is described here.