Contemporary Music
Instruction and Mentoring
Problems with Tuning Guitars
Trying
to tune a guitar precisely is an exercise in
futility. It is near impossible to get even
a well-set-up, high-end guitar to play in tune
with itself and with other instruments on every
chord and on every note along the length of the
neck.
Have you ever noticed that if you tune your guitar
perfectly with a quality headstock tuner and then
play a “D” chord, that the octave D that is
fretted on fret 3 on the #2 B string is sharp and
the chord sounds badly out of tune? It’s not
your imagination, and no the string didn’t slip
out of tune after you tuned it perfectly with your
tuner. It is the nature of guitars.
Guitars are very imprecise on pitch. It is
an insolvable problem that is inherent due to
their design.
Part of the problem is due to what is called
“equal temperament tuning” which is what all fixed
pitch instruments are tuned to, and have been
since Bach’s day. In order for 4ths, 5ths,
3rds to be perfectly in tune in a particular key,
they will be WAY out of tune in any other key.
Here’s the problem: if you tune a piano A and E to
be a perfect fifth apart, and then tune the B to
the E in a perfect fourth, and then the F# to the
B, and so on, and go around the Circle of Fifths,
when you finally get back to the next A, if will
be WAY out of tune from the original A. This
is an unsolvable mathematical problem. Way
back when keyboard instruments were first
invented, they would be tuned for a particular
piece of music. But if there were chords
with notes that were not on that scale, or if the
music changed key signatures in the middle of the
piece, or if there were two pieces of music on the
program in different keys, there was no solution
except to have two harpsichords tuned differently
from each other. Around Bach’s time,
somebody figured out that if you tune all the
notes in a way that all intervals are slightly out
of tune from each other, you can make every chord
in every key equally out of tune, but is barely
noticeable. This was called “equal
temperament,” or "well tempered" tuning.
Wikipedia has a good article on equal temperament
tuning: https://en.wikipedia.org/wiki/Equal_temperament.
Technically, equal temperament means that all 12
notes adjacent to each other in an octave are
tuned a mathematically equal distance in pitch
from each other. From a practical
standpoint, it means that each interval is more or
less “equally out of tune”. How much is it
out of tune? Each fourth and fifth is
approximately 3 beats every 5 seconds out of
tune. So even if our pianos and guitars are
tuned exactly with an electronic tuner that is set
to equal temperament, every chord is slightly out
of tune. Theoretically, the octaves should
be in tune, but that’s all that is perfectly in
tune.
The great classical composers loved equal
temperament because it gave them complete harmonic
freedom in their pieces at the expense of just a
little impurity in every interval, which gave all
sorts of flexibility on compositions for keyboard
instruments. Equal temperament tuning is
what we have heard all our lives, because that’s
the only way keyboard instruments have been tuned
for the last several hundred years. We are
so conditioned to hearing 3 beats every 5 seconds
on 4ths and 5ths (and worse on 3rds) that we don't
even notice it.
Thus, pretty much all the music we hear is out of
tune. We’re conditioned to it. That’s
why when we hear a really good a'cappella choir
singing in perfect harmonies without any vibrato
it sends chills up our spines, and we wonder why.
In addition to equal temperament, guitars have
several other problems that make them out of tune
with themselves and with other instruments. Think
about the three things that determine pitch on a
guitar (or on any stringed instrument): string
length, string tension, and string gauge
(thickness). Length changes when we fret the
string on different frets on the fretboard.
Tension changes when we turn the tuning
machines. Gauge is what causes the six
strings that all are the same length and close to
the same tension to sound different pitches from
each other (thicker strings have more mass and
thus vibrate more slowly than thin strings and
therefore sound lower pitches). These three
things interact to cause tuning problems on
guitars. Guitar makers try to compensate by
changing the angle of the saddle, and compensating
the top of the saddle, to make the six strings
different lengths.
Tension is the most problematic of the
three. For example, the pitch of any guitar
string goes from sharp to flat as it is picked
hard and then settles as it vibrates less
strongly. You can see this very clearly with a
chromatic tuner that has an old fashioned analog
meter with a mechanical needle. When you
first hit the string, the needle jumps sharp and
then it gradually goes down. This is caused by the
change in string tension from the string
stretching itself during the wide vibration right
after you pluck it. The wider the distance that
the middle of the string wobbles, the more it
stretches itself and the sharper it goes. How far
it wobbles and therefore how sharp it goes varies
depending on the gauge and tension of the string,
and how hard you pluck it. That is why if
you tune with a tuner, the bottom E will always be
sharper than the top E right after you pluck the
strings (unless you pluck very softly), then if
you let them ring for a second, they will both be
in tune. (Theoretically, pianos also have
this problem, but it is very tiny compared to
guitars because the length of the strings is so
much longer and the tension of the strings is so
much higher that the pitch change right after a
hard strike is very small even when hit very
hard.)
Guitars have the additional problem of stretching
the string while we press it to the fret, which
also increases the string tension and makes the
pitch go sharp. The farther the string is
from the fret, the more the string is stretched to
reach the fret. Guitar makers try to account
for this by carefully measuring where the frets
are placed on the neck and with the shape of the
saddle, but it’s just an estimate and it’s never
perfect. It is inevitable that your guitar
will ALWAYS either have a different gauge of
strings, or different nut groove height, or
different saddle height, or different truss rod
adjustment, or your neck will have a slightly
different shape than the one they used for their
calculations. This is one of the reasons why
set up (nut slot depth, truss rod adjustment, and
saddle height) is so important: unless the guitar
is set up perfectly, every fretted string will be
sharp or flat (usually sharp) relative to every
open string.
Furthermore, the harder you press the string past
the fret towards the fret board, the sharper it
goes. This can be a big problem with
jumbo/tall frets and a player that presses the
strings hard. Also, if you don't use proper
technique and bend the string sideways while
pressing it, that will further aggravate the
"going sharp" problem.
Anytime we stick a capo on a guitar (unless we
take the time to re-tune it with the capo on) we
double the problem because the capo bends all the
strings all the way to the fretboard, so they are
pre-stretched a lot so they're all sharp relative
to other instruments. Then we fret them with
our fingers and stretch them even more.
Finally, steel string acoustic guitars have one
additional problem that makes them out of tune
with themselves, and that is the nature of the
wooden soundboard and the bracing required to hold
soundboard in place. There is a complex
conundrum in designing soundboard bracing which
involves a compromise between tone, volume,
sustain, intonation, and strength. When a
guitar designer tries to improve one thing, it
often negatively affects something else. The
bottom line is, on most guitars made before 2018,
even one string played by itself can sound out of
tune with itself on certain frets because of the
nature of the vibrations of the wood. In
2018, Taylor introduced a new type of bracing that
greatly reduces the intonation problems while
providing excellent volume and sustain. I
have one high-end Taylor with the new V-class
bracing and another with the old X-class
bracing. The difference is subtle, but
definitely noticeable.
In summary, to say a guitar is “not very precise”
on tuning is a gross understatement. But
there are things we can do that can help.
First, get a good setup from a competent
luthier. This will get the strings at the
right height so they don't have to bend so much
when pressing them to the frets.
Second, learn the correct way to change
strings. When installing strings, make sure
the tuning machines are tightly installed and
mechanically okay. Wind each string tightly
around the peg. Stretch the strings before
tuning. Watch this video: https://www.youtube.com/watch?v=80EuGOXgoOo.
Third and most importantly, learn the proper way
to tune a guitar. NEVER tune a string from
sharp down to the correct pitch. ALWAYS tune
a string from flat up to the correct pitch.
After all six strings are tuned, strum the guitar
several times strongly, then check the pitch again
and correct any strings that are out.
Fourth, don't just blindly follow the tuner.
Just because your tuner glows green on all six
strings does not mean it's in tune. Most
digital tuners glow green for too wide of a range
of micro pitches. And even if you're smack
in the middle of the green range on all six
strings, sometimes when you play you'll hear
slight problems.
For example, many guitarists tune String 2 (B) a
couple of cents flat. On most guitars, the B
string is the problem child. It’s the one
that sounds bad more often than the others.
Tuning it a couple of cents flat helps a lot on D
chords (but it makes some other chords slightly
worse.)
The famous folk guitarist James Taylor recommends
the following tuning (this is only possible if you
use a chromatic tuner accurate to 1 cent):
6E: -12 cents
5A: -10 cents
4D: -8 cents
3G: -4 cents
2B: -6 cents
1E: -3 cents
As you can see, this compensates for the problem
of the thicker strings going more sharp when
struck hard. You’ll also notice that the B
string is tuned much lower than it ought to be
compared to its neighboring strings. But
this is a compromise that only works if you’re
constantly strumming. If you let the strings
ring, they will end up quite flat compared to the
other instruments.
The book, “The Acoustic Guitar Bible” describes
what is called the Failsafe Tuning Method, that
makes all chords sound reasonably in tune, and
none of them grate. Here it is:
Tune the high e string as desired
Tune the 12th fret harmonic of the B string to the
high e string fretted at the 7th fret
Tune the 12th fret harmonic of the G string to the
high e string fretted at the 3rd fret
Tune the 12th fret harmonic of the D string to the
B string fretted at the 3rd fret
Tune the 12th fret harmonic of the A string to the
G string fretted at the 2nd fret
Tune the 12th fret harmonic of the low E string to
the D string fretted at the 2nd fret
Once you've done that, use the following two
chords to test your tuning because, for whatever
reason, they are particularly sensitive to
inaccuracies:
E5: 079900
A5/E: 002255
People who have trained themselves using this
method swear by it.
As for myself, I am a pragmatist. Because I
mostly finger pick and don't hit the strings super
hard very often, my overall philosophy has
generally been to tune with the tuner and just set
the B string a touch flat so that the D chord
doesn't sound like crap. With most headstock
tuners, each LED has a couple of cents range.
(Some of them a lot more than a couple of cents).
Using my TC Electronic Polytune tuner on my
Taylor, I generally tune the B string by slowly
starting flat and very slowly tuning up until the
green LED just barely lights, and that makes it
just a touch flat. The other five strings I
try to get in the "middle" of the green range.
The truth of the matter is, if you are playing
popular music in an ensemble or band, nobody can
hear the difference, anyway. When I play
with other guitarists and bassists, the various
instruments are usually far enough out of tune
with each other that nobody can hear the
difference of a few cents on one guitar. If I
could just get those the other guitarists to
always go below the pitch and then tune up to the
pitch then strum the strings hard a few times and
then check each string again, I'd be happy. A
couple of cents here or there on my guitar will
never be heard.
(Incidentally, this has nothing to do with
guitars, but pianos have an additional problem
caused by the variety of length and thicknesses of
the strings and the huge range in pitch: perfectly
tuned octaves sound out of tune to human ears from
the top to the bottom of the piano. This is not
related to equal temperament, it is a different
problem: we hear pitch differently than
mathematical formulas say we should. To the
human ear, a piano tuned perfectly sounds flat at
the top of the piano and sharp at the
bottom. For this reason, good piano tuners
"stretch tune" at the top and bottom ranges.
An expertly tuned grand piano might be as much as
10-15 cents sharp on the top strings and 5-10
cents flat on the bottom strings. Guitars
don't have this problem because they don't go
anywhere near the pitches at the top and bottom of
the piano.)