Understanding the B String Gap

One mark of the advancing guitar player is that they begin to come to grips with the B string gap, that oddity of guitar tuning that causes fretboard shapes and patterns to appear different when they cross over the B string.

First, a primer on guitar tuning is in order.

Guitar Tuning System

The guitar has six strings. One feature of the guitar is that both the highest and lowest strings are tuned to the same note, E, and this lends a semi-symmetrical feeling to the guitar neck. If we play the note on the lowest string, fret III it is exactly two octaves below that of the IIIrd fret on the highest string.

This symmetry makes the guitar a logical instrument in some ways. And without this, we wouldn’t really be able to use barre chords as much because there would be too many different notes resulting from a single finger pressing every string on the same fret. Unfortunately, there is no way to divide that two octaves evenly by any single interval across six strings. If we started on E and tuned the guitar to fourths (5 half-steps difference between each string), we would have:

All Fourths Tuning

This goes over the two octaves and creates a weird result.

So if we use an interval greater than a fourth we'll be even less able to reach our desired two octave range, because we'll overshoot it. And most of them would have even weirder results.

All Thirds Tuning

If we do major thirds, we get this:

This is almost like a weird open tuning for augmented chords. It’s not that useful.

So it seems that to create a two-octave range between the 6 strings, we need to use some combination of fourths and thirds. We cannot consistently use the same interval.

So the compromise that evolved was to tune the guitar to what is now considered standard tuning.

Standard Tuning

In this tuning scheme, we have a tuning of fourths for the lowest four strings, and then there’s suddenly a third from G to B, before we have another fourth taking us back to E—two octaves above the lowest string.

Some decisions of this tuning, you may find, are arbitrary. For example, the same intervals could have been used, but one step lower:

Standard Tuning, One Step Lower

Or, the third could be moved from the third and second strings to the second and first strings:

Four Fourths and a Third

Overall, standard tuning stands for a number of reasons:

• The low strings, tuned to EADG, match the tuning for the classical upright bass, which was also the inspiration for the tuning of the bass guitar.
• Standard tuning consists of all natural notes, allowing for easier playing in common keys such as C major or G major.
• Standard tuning allows for a two octave chromatic scale to be played from the lowest to highest string. When playing melodies, notes tend to move in intervals of smaller than one octave, so they should all be within reach of each other.
• Most chords can be played without unreasonable difficulty.
• The two-octave distance between the 6^th and 1^st strings makes barre chords easier.
• Now that this tuning is so widely used, all guitar players start here.

How this Affects Guitar Players

Intermediate and advanced guitar players will begin to hear the notes before they play them. This hearing is made more difficult by the fact that one of the strings is tuned to a different interval. Suddenly, crossing over the line of the B string means that the pattern visually does not match the other strings. This happens when trying to copy any pattern from the bottom four strings (EADG) to any position where it will move onto the B string (or the high E string, for that matter). As a result of the B string’s tuning in a third, the high E string is also different when compared to the third string.

Visualizing the Gap

One great way to visualize how the gap works is to practice playing chords, scales or arpeggios (structures) that span across two, three, or four strings and compare them across different string sets.

Take for example the drop 2 major 7^th chord.

This chord has a root, a fifth, a major 7th, and a major 10th (the third, up an octave).

Move this structure on to the middle four strings, and you get this shape:

Note that it is still the exact same configuration in terms of intervals. But because the b string of the guitar is tuned to a third instead of a fourth, that note appears one semitone or fret higher, but actually it’s the same note.

Now let’s move it to the top four strings.

Here things get even more interesting. The root and fifth maintain the same original shape (C to G). However, the 7^th now crosses over to the B string, which we know is one half-step lower, so it must be "raised" by one fret in order to be equal to the same interval it had been before. In addition, the highest note, E, also appears to be raised! Although the 1^st and 2^nd strings are a fourth apart from each other, that major 10^th which crosses from the C on the fourth string, over the boundary of the B string, and onto the E string, has also changed its shape.

Put it into Practice

Practice and visualize patterns such as intervals, octaves, closed chords, single octave scales and arpeggios, and move them across to different string sets. When you find that crossing this boundary feels effortless and subconscious, you will know you are moving towards a new level of guitar playing.