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Natural harmonics The physics of vibrating strings is a complex subject in which
I have no expertise, other than twanging music out of them,
so I won't pretend to know the details. I do know that when
you strike a guitar string, the note that you hear is called
the 'fundamental'. It's by far the loudest note created, but
along with it you are also hearing 'harmonics'. These are subsidiary
tones that accompany the fundamental, and are responsible for
making each instrument sound the way it does. Guitar 'harmonics'
are created when you lightly touch the string with your finger
at specific positions and then pluck the string. This causes
both sections of the string, to the right and left of the spot
you're touching, to vibrate simultaneously, giving a bell like
quality to the note. It's best to quickly remove your finger
as you pluck. What you are doing is removing the fundamental
and only hearing the harmonics.
There are three points along the string points this:
the fifth, seventh and twelfth frets ... directly above the
fret-wire. At these points, the string is divided exactly
into fourths, thirds and halves respectively. The purity
of sound comes from these perfect fractions of string ringing
together. If you try it anywhere else on the string, you
hear a dead sound without any ring.
The movie shoes the technique quite well. You never push
down on the string, all you need is to very lightly touch
it and as soon as you've plucked it with the other hand,
stop touching it. It takes a little while to master, a bit
like rubbing a note out of the rim of a wine glass, but once
you get it, you've got it forever.
The notes created are not always the same notes as the fretted
note.
At the 12th fret, they are the same note, and in fact playing
one after the other is a good way to see if the intonation
on your instrument is right: both fretted note and harmonic
should be identical in pitch. If they're not, your bridge
needs adjusting.
At the 7th fret, the harmonic is one octave higher than
the fretted note.
At the 5th fret, the harmonic is the 'fifth' of the fretted
note, but 2 octaves higher. In other words, on the E string,
the fretted note at the 5th fret is an A note, but the harmonic
played at the 5th fret is an E note two octaves higher.
You can see in the movie I play a few at the 12th fret,
then a few at the 7th and 5th frets. I then play a little
melodic line using harmonics from the 12th and 7th frets. These
open string harmonics are the 'natural
harmonics'.
Artificial harmonics
Artificial harmonics are those created on a
string that's already fretted by the left hand. The right
hand must do the light touch AND the pluck at the same time,
AND the position of the light touch must be five, seven or
(usually) twelve frets away from the fretting hand ... a lot
to think about.
In the second movie, I play through the chords to Stairway
to Heaven, in harmonics. To do this I have to mirror exactly
what I'm playing with the left hand ... 12 frets up the neck.
I'm following the same chord shapes up an octave, and doing
the light-touch/pluck with the right hand. The movie shows
how I do that: my index finger is doing the light touch, and
the ring finger on that same hand is doing the plucking. I
must remove the finger tip as I pluck to get the harmonic.
This is not a technique I use often, and you can hear I'm not
very good at it. It's a little easier to get a good consistent
ring out of an electric guitar.
Harmonics are usually used as embellishment, rarely as any
main guitar part. |
