What is “Harmonics”?
Before we talk about the guitar harmonics, and how to play harmonics on a guitar, first we need to understand what “harmonics” is.
“Harmonics”, is actually a scientific term, more accurately a physics term. To understand it we have to first understand sound waves, but since this is not a physics lesson, nor it is related to science in any way, I will make it very simple and brief.
When you hear a single musical note, your ear perceives it as a simple “one” note. But in fact, beneath this “one” note lies infinite other “notes” that are too quiet for our ears to hear them. These other little notes also vibrates in different, higher frequencies than the actual note you are hearing, and these frequencies are always a multiple of whole numbers (integer) of the first, fundamental note's frequency.
Check the following chart of a fundamental frequency signal (n=1), followed by 3 higher frequency signals (n=2,3 and 4):
All these signals combined to produce one note, or one sound, including the fundamental first one, are called “Harmonics”.
What gives each instrument its unique voice?
Why then, the C key, for example, on the guitar sound different than the C key on the violin? or piano? if they have the same signal amplitude and frequency.
To answer that, you have to understand that each instrument is built differently, with different various materials comprising the body, neck, and strings. Even two instruments of the same type (for example two classical guitars) will never sound exactly the same, because the wood and the strings would be slightly different depending on age, usage, and quality.
With that being said, when a note is played, it will produce a single fundamental wave sound signal, followed by endless, distinct and complicated other signals that are higher in frequency, but much lower amplitude, and all these waves together (including the fundamental one) are called Harmonics and they comprise that distinct, unique sound that you are hearing when you play on the guitar, violin, piano, or any other instrument.
If you played the same key on other instruments, you will get the same fundamental signal followed by different other unique harmonics, and this is why instruments and human voices have different sounds.
Harmonics on Guitar
Harmonics on guitar is used to describe that peculiar, ringing sound when you lay a finger on a string and just slightly press it down (less than a quarter down).
Now, you can't get that ringing sound just on any place on the guitar, there are specific places on the fretboard where you can get harmonics on, and these places are normal found on the 5th, 7th, and 12th fret.
However, there are more, depending on the length of the string (for example, if you have a capo on, then the harmonic fret would shift accordingly), here is a chart of harmonic nodes found on the neck of the guitar taken from Wikipedia:
By lightly touching on the specified nodes to produce harmonics, you are actually “silencing” the fundamental wave sound along with all the other overtones, EXCEPT ones that have a node at that location. And these wave sounds that are left are the ones causing the harmonic, unique ringing sound that you hear on the guitar.
The specified node locations on the fretboard are not random or accidental, but rather, happened “naturally” because of the length of the string that dictates the number of notes that you can get by fretting it.
Remember what we talked earlier, the harmonics are of WHOLE, integer multiplier of the fundamental harmonic wave.
If the fundamental wave have a value frequency of “1”, the next harmonic would be half, or “1/2”, multiply the “1/2” with 2 and you get the fundamental wave.
The same thing with the “1/3” harmonic, multiply it with 3 and you get the fundamental wave, and so on.
ALL the nodes mentioned above can produce a ringing harmonic sound because at the specified node's location, you are getting one of these “frequencies” that are of integer multiplier of the fundamental wave tone.
The 12th fret would be one octave higher, with a fraction of “1/2” or half of the fundamental frequency. 7th fret being the “1/3” fraction, and 5th being the “1/4”.
Below is a good video demonstration on how to play harmonics on the guitar:
Artificial Harmonics is a term used to express the creation of other harmonics on the fretboard than the one we discussed earlier (Which are called Natural Harmonics), by manipulating the “length” of the string. Using your fingers or a capo, you can shorten the string and thus create a different string length with different fundamental sound wave and frequency.
Doing that will enable you to shift the nodes on the fretboard that are known by default to produce harmonics, to other locations on the fretboard that would otherwise be impossible to get, depending on the length of string that you have created.
Playing artificial harmonics can be very challenging and requires lots of practice and attention, because first you are used to the original locations of the harmonics (5th, 7th and 12th, etc), and second, by shifting the nodes forward, you can get harmonics nodes very high up the neck of the guitar where you have strings without frets, and there, you simply have to memorize these locations by spotting different features on the guitar and remembering them, which requires strong visual memory, and of course, lots of practice.
But, succeeding in doing that you will surely get rewarded with a unique, special sound that is hard to find in many other music compositions.
So in this article we've learned more about what harmonics is both as a scientific term, and musical term. We learned about the nature of harmonics and sound waves, and how to create them on the guitar. Why they sound like this, and how to locate them on the fretboard of your guitar.
Harmonics is another tool you can use to add more complexity, diversity, and versatility into your guitar playing, many guitarists utilize them in different ways, some heavy rock and metal guitarists like Zakk Wylde and Van Halen utilize harmonics in a more aggressive form, which simply make their solos sound furious and on fire.
Some use them as a way to create some kind of “echo-sustain” effects, like the harmonics used on the 12th frets in the intro to Nothing Else Matters by Metallica.
Knowing how to use them, and when, will surely add to the value and the complexity of whatever it is that you are playing.
I hope you enjoyed this article, and was helpful enough to clear the image in your head about harmonics on guitar, and how to play them.
If you have any questions or feedback regarding this topic, please feel free to leave a comment below and I will reply as soon as I can.