It may be true that we guitarists spend half of our lives tuning and the other half playing out of tune, but at least we don’t have to have someone come over to tune our instrument, like pianists often do; and then play out-of-tune anyway! Yes, a freshly tuned piano has many note combinations that are simply not in tune… as a matter of fact, only the octaves are “clean.” But you want to know exactly how to tune a guitar, and in this essay, I would like to present my thoughts on the matter. I spend a bit of time helping my students properly tune during their guitar lessons.
How to tune a guitar – physics
The problem of tuning stems from a discrepancy between the interval of the fifth as it occurs in an equally partitioned octave with 12 steps and the mathematically correct (and acoustically “clean”) fifth found in the harmonic series. In today’s standard tuning, known as equal temperament, all intervals, with the exception of the octave, are tweaked in order to homogenize the distance between all half steps. Some intervals, like the fifth, are slightly compressed; others, like the fourth, are slightly expanded.
When it comes to tuning guitars, we encounter an interesting dilemma. The horizontal dimension (going up and down the fret board) is perfectly equal-tempered (i.e. the positions of each fret along the fret board are successively divided by a constant, each time subtracting the quotient.) Vertically (from string to string), however, guitarists tend to tune clean, i.e. not equal-tempered. As a result, guitarists – just like piano tuners – have to make compromises and choices. Luckily, we guitarists can make these compromises and choices from piece to piece, since re-tuning a guitar is a matter of seconds. Below is my personal way of tuning and re-tuning my guitar.
As my reference point I like to use the note A, preferably 110Hz, 220Hz or 440Hz. I choose A for four reasons:
1) A exists as an open string (110Hz) on the guitar (i.e. the 5th string).
2) A is generally the note to which a tuning fork is tuned (and a tuning fork is a great tool that requires no electricity and can be easily carried around).
3) 110Hz A lies in a fairly low register that allows the ear to detect “beats” with relative ease.
4) By using the A-string as my reference point, I can tune the 6th, the 4th and the 1st string directly to the source, without a mediator, and by using only open strings and harmonics (no farther than the third partial). The 2nd and 3rd strings need mediators that have to be determined by the key in which the guitarist intends to play.
What follows is the process by which I like to tune my guitar. As a general rule, always tune up to the correct pitch not down, which may result in an unstable tuning. Harmonics are produced by lightly touching the string at specific points (known as nodes). The nodes correspond to certain frets. The second partial (the first being the fundamental, i.e. the open string), for example, is produced by touching the string at the 12th fret. However, the finger should be right over the respective fret, rather than slightly behind, as is the case when we actually fret a note. It is also advisable to pluck the string somewhat close (ca. 2 ½ inches) to the bridge. Doing so will bring out the overtones.
In order to avoid lengthy explanations, harmonics over the 12th and 7th fret will be referred to as the 2nd and 3rd partials, respectively. I have divided the process into two methods. The first is is a better method, which requires more training. The second method for tuning a guitar is for beginning guitarists, who may have difficulty matching pitch and identifying octaves.
How to tune a guitar – Advanced Method
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1) Tune the 5th string to a tuning fork or get the pitch from another instrument if you are to play as an ensemble. (Same as 1 above)
2) Produce the 2nd partial of the 5th string (harmonic on 12th fret) and compare to the 3rd partial on the 4th string (7th fret harmonic). They should be an octave apart. Tune the 4th string so that the harmonic is exactly one octave higher than the 5th string’s harmonic.
3) This step is a repeat of step 2 on strings 4 and 3. Produce the 2nd partial of the 4th string (harmonic on 12th fret) and compare to the 3rd partial on the 3rd string (7th fret harmonic). They should be an octave apart. Tune the 3rd string so that the harmonic is exactly one octave higher than the 4th string’s harmonic. Check the octave between the open 5th string and 2nd fret 3rd string (not a harmonic). This is important, especially for pieces in A major/minor and in D major/minor.
4) This step is a repeat of step 2 on the 6th and 5th strings. Produce the 2nd partial of the 6th string (harmonic on 12th fret) and compare to the 3rd partial on the 5th string (7th fret harmonic). They should be an octave apart. Tune the 6th string so that the harmonic is exactly one octave higher than the 5th string’s harmonic.In addition, sound the open 1st string, which should sound the same as the 2nd partial of the 5th string.
5) Produce the harmonic on the 6th string, 7th fret. This should give you the note of the 2nd string. Tune the 2nd string to the harmonic of the 6th string. However, the 2nd string should be adjusted either to produce a “clean-
enough” perfect fourth with the 1st string, or to produce a clean octave with the open 4th string when fretted at the 3rd fret.
In either case it is mandatory to tune up – rather than down – to the correct pitch; not only because of tuning stability,
but also because our ears tend to accept intervals as in-tune as we approach the correct pitch, slightly before the interval
is actually beat-free (i.e. mathematically in tune). This lucky coincidence facilitates a compromise that is between equal
temperament and just intonation.
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The following method for tuning the guitar is intended for beginners who may have trouble matching pitch or matching octaves as described above. Watch the video below for a demonstration.
How to tune a guitar – Beginner’s method
1) Tune the 5th string (A) to a tuning fork or get the pitch from another instrument if you are to play as an ensemble.
2) Fret (press) the 6th string (E) at the 5th fret and compare the resulting tone to the open 5th string. They should sound the same. Tune the 6th string to match the 5th.
3) Fret the 5th string at the 5th fret and tune the 4th string (D) until it sounds just like to fretted note on the 5th string.
4) Fret the 4th string at the 5th fret and tune the 3rd string (G) until it sounds just like to fretted note on the 4th string.
5) Produce the harmonic (see above) on the 5th string, 7th fret. This will give you the note of the 1st string. Tune the 1st string to harmonic on the 5th string.
6) Produce the harmonic on the 6th string, 7th fret. This should give you the note of the 2nd string. Tune the 2nd string to the harmonic of the 6th string.