Harmonics

author: ZeGuitarist date: 10/20/2008 category: guitar techniques
rating: 9.5 / votes: 159 

Introduction

A. Problem: Like in my last lesson (Economy picking), I will start by pointing out a problem that has occurred to me on UG.com, and then I will come up with a solution. The problem is again the lack of useful and clear explanations on a certain guitar technique: harmonics. The available lessons all handle one single aspect of harmonics, but nobody seems to get the bigger picture. How can you fully understand harmonics, if you only learn one aspect of it? For example, what's the use of knowing how to produce an artificial harmonic if you don't understand the whole concept of harmonics first? B. Solution: In this lesson, I will try and explain the concept of harmonics in all its varieties. To do this, I will make use of the information available in the lessons that are currently up on UG.com, and organise it in a logical order, so that everybody can understand easily what harmonics really are, and how you can use them in your playing. (I will not copy any information used in these previous lessons! I respect the work of the authors, so I will only use and adapt parts of information that I need, and explain them to you in my OWN way...)

What Are Harmonics?

To fully understand the concept of harmonics, I should begin with an explanation about what a harmonic in fact is. It's a little music theory, you can skip this if you really hate this but I advise that you read it anyway, it's easier to understand the rest of the lesson if you do. A. Harmonics = Sound Waves: As you probably know already, sound consists of sound waves. (Logic, isn't it?) The guitar produces sound because the strings vibrate and produce waves, which means sound. But a guitar string (or any other string) doesn't just produce any wave. A sound wave consists of different waves, which vibrate at different frequencies; the mathematical sum of all those frequencies results in the actual sound that we hear. This means, when you pluck a guitar string, you hear one tone, but there are in fact more tones sounding at the same time. I will try to explain it more clearly with an image (I just got it off the first URL on Google, so sorry to the owner, I hope I'm free to use it...). On the image, you see an open E string (the thick, low string) which is now vibrating. You can see several vibrations on the image; I will now explain to you what they mean. The uppermost image is the string, vibrating between the bridge and the nut. You can see that the amplitude of the vibration is the greatest in the middle (this means, the motion up and down that the string makes is the greatest in the middle). You can also see that the string doesn't vibrate at all right above the bridge and the nut. Logic, because the bridge and the nut keep the string in place! The middle image shows the same string vibrating, but not in the same way. This time, the amplitude of the vibration is not the greatest in the middle, but at and of the string. You can see that in the middle of the string, there is a point where there is no vibration at all! From now on, we will call these points nodes. They will be very important in the rest of this lesson, so remember! Nodes are points where the string does not vibrate. On either side of the node, the string DOES vibrate, so there's still a sound! The bottom image shows the same string, vibrating in yet another fashion. This time, there are two nodes, and the string is vibrating around them at yet another frequency. So now we have one string, vibrating at three different frequencies! And there are a lot more frequencies that the image doesn't show! What does this all mean, a lot of you might ask by now? I will explain it to you now! As I said before, a tone produced by a guitar actually consists of more tones sounding at the same time. This is because a guitar string doesn't vibrate at one frequency, but at more frequencies at the same time! The mathematical sum of these frequencies results in the tone that you hear. All of these frequencies are called harmonics. The top image on the picture above shows the first harmonic of the string. It has two nodes, one on every end of the string. The string just vibrates in between the nodes. The first harmonic is the most important harmonic, because it produces the exact note that we hear when we play the string (in this case, E). You only hear the first harmonic and not the other ones because the vibration of the first harmonic is much stronger than those of the second, third, harmonics. The first harmonic is in fact the fundament of the note we hear: it defines the actual pitch of the note. We call it the fundamental. The middle image shows the second harmonic: this time, there's a node in the middle of the string, dividing the string in 2 equally long parts, vibrating at a higher frequency than the first harmonic. Therefore, it produces a higher sound (one octave), which you can't hear because it is dominated by the fundamental. The bottom image is the third harmonic: again, the parts of string in between the nodes vibrate at a higher frequency, resulting in a higher tone. There are even more harmonics: fourth, fifth, All of them vibrate at a higher frequency and add a certain percentage of tone to the fundamental tone. All of these harmonics are called overtones: they add a certain amount of a different pitch to the fundamental tone. That is why a guitar string doesn't sound the same as a piano string, or a harp string. In every string, the percentage of sound that every harmonic adds to the fundamental differs; so you can play the same note on a guitar and a piano string, they will sound different. (This is called the timbre of an instrument.) B. Producing Harmonics: I will now explain how you can make the subtle sound of the harmonics (which you normally don't hear) instead of playing the fundamental note of the string. The trick is to cancel out the vibrations that you don't want to hear, to make the sound that you want stand out. This means, you can hear the harmonics if you somehow succeed in muting the fundamental note. The problem with this is that you only need to mute the fundamental vibration of the string, but not the entire string, because then you will have no sound at all! I will now try and explain how this is done. Remember the nodes? In every harmonic vibration, there are certain points where the string doesn't vibrate at all. We can use these if we want to cancel out certain vibration frequencies; in fact, they are the key to producing harmonics! An example: on the E string, we will now try and produce the second harmonic, so we are going to mute the fundamental vibration. How do we do this? Notice that the amplitude of the fundamental vibration is the greatest in the middle (right above the 12th fret), while in the second harmonic vibration, the middle is a node, so it doesn't vibrate at all. If you touch the string lightly with your finger right above the 12th fret (don't press it down, just touch the string very lightly), and pluck the string, the fundamental note will no longer be heard. That's logic, because your finger mutes the string in a place where it would normally vibrate the hardest! On the other hand, you will notice that there's still a bell-like, subtle sound produced by the string. This is the second harmonic you hear: it was not affected by your finger, because at the point where your finger is muting the string, the harmonic didn't vibrate anyway. The vibration on either side of the node can therefore still continue, so the harmonic sound can still be heard! (NOTE: do remove your finger from the node immediately after you have produced the harmonic, because otherwise you WILL mute the harmonic note in the end!) What we have done now is quite simple: we muted the fundamental note, but allowed the second harmonic to continue vibrating, so that we can now hear the harmonic note. You can do the same with the third harmonic: touch the string above the nodes of the vibration (see image: fret 7 or 19), pluck it, and you will hear only the third harmonic, because you cancelled out the fundamental and the second harmonic. This goes for any other harmonic! That's it for the theory, I will now continue with the practical side of harmonics. So now we know that we can produce harmonic sounds by touching the string in the correct place with your finger; that is where the node of a certain vibration is. Now you all want to know how to use this knowledge in your playing, of course! I will now explain how you can produce harmonics in practice, both natural and artificial harmonics.

Natural Harmonics

What natural harmonics are, you already know. Natural harmonics are harmonics produced on an open string, just like the example I just gave. We produce natural harmonics by touching the string lightly in the correct place, cancelling out certain vibrations, leaving the harmonic note to stand out. Where can you find these nodes on the string? Below is a diagram of the most common natural harmonics (also just found on Google): Fig. 1 shows the fundamental, which we don't need now. Fig. 2 shows the second harmonic, with a node right above the 12th fret. This means, to produce the second harmonic, you just touch the string lightly right above the 12th fret. You will hear a note one octave higher than the fundamental. For the 3rd harmonic, you can either touch the string over the 7th or the 19th fret: the note you hear will be one octave higher, plus the fifth note. (It's not important if you don't know what this means, just remember that the note you hear will be higher for each number of harmonic.) For the 4th harmonic, there are 2 possible locations: the 5th fret and the 24th fret. The 4th harmonic also has a node on the 12th fret, but if you touch the string there, you will not cancel out the second harmonic, so the 4th harmonic will not stand out. There are more harmonics then the image shows, but they are less common because they are less strong. It's difficult to make them stand out because they produce so little sound. With an electric guitar however, you can amplify the sound of these harmonics using gain/distortion. This way, it's possible to produce harmonic notes over the 4th fret, right below the 3rd fret, in the middle of the 2nd and 3rd fret, And a lot more! Experiment a little, try to produce more harmonics using distortion to amplify them.

Artificial harmonics

Artificial harmonics is actually a bad name, because they are just as real as natural harmonics. The only difference is: artificial harmonics aren't played on open strings, but on strings that are fretted (pressed down with your left hand). Pressing a string down behind a certain fret actually alters the length of the string (which is why it produces a different note than the open string!); this also means that the nodes of the harmonics will be in a different location now! This results in two problems: 1. We don't know the exact location of the nodes anymore, so we don't know where to touch the string to produce a harmonic note. 2. Even if we would know, how do we touch the string in that location? Because your left hand is busy, pressing down strings, you can't use your left hand for both actions For each of these problems is a solution. II will first explain the two techniques that are used to touch the string to produce the harmonic note, using your pick hand. This solves problem number 2. I will then give a very simple answer to problem number 1. A. Right Hand Technique: Pinch Say, you are fretting the 3d string on the 5th fret. I just choose randomly, because artificial harmonics can be produced on any position! Let's say you know exactly where the node for the second harmonic is (in fact, it should be right in the middle of the 5th fret and the bridge). What we do to produce this harmonic, in several steps:
  • Place your pick right above the location of the desired node. Only a few millimetres of the tip of your pick should protrude from between your thumb and index finger.
  • Pluck the string with your pick (with a downstroke).
  • All in the same downstroke motion, touch the string lightly (in the correct location!) with the side of your thumb. This is the tricky part of the technique: you are supposed to pluck the string with your pick, and then your thumb, which follows up right after the pick, has to touch the string right on the node, so that the fundamental is cancelled out. (NOTE: again, be sure not to rest your thumb on the string, just touch it and pull back, otherwise you will mute the string completely!) This technique is called pinch, because the string is in some way pinched between the pick and the side of the thumb. It takes a while to master this technique, so keep practicing and don't give up! It's easier to pull off if only a small part of the pick protrudes from between the fingers; this way, your thumb is closer to the string if you pluck it with your pick. This will make it easier to pluck the string and touch it in one fluent motion. You should first practice this movement slowly: pluck the string so you hear the fundamental, then mute the fundamental by placing your thumb on the string in the appropriate place. If you can pull this off properly, try to do it faster, so that the thumb touches the string immediately after it is plucked. If you do this correctly, you will not even hear the fundamental anymore! Only the high-pitched, squealing sound of the harmonic remains. This is why artificial harmonics are also called pinch harmonics or squealies. B. Another Right Hand Technique: Tapped Harmonics Another less commonly (but equally cool!) right hand technique used to produce artificial harmonics is the tap technique. I will use the same example as above: we fretted the 3rd string at the 5th fret and we want to produce an artificial harmonic. We will now use the tap technique instead of the pinch technique, to produce the 2nd harmonic for this note:
  • Pluck the string. (easy, isn't it?). You will now hear the fundamental note, which we will cancel out using the tap technique in a second.
  • Move your right hand to a position 12 frets higher than where the note is fretted by your left hand. In this case, we fretted the note at the 5th fret, so we move our right hand to right above the 17th fret. This is the node for the 2nd harmonic.
  • Very quickly tap the vibrating string at the node, not pressing it down to the fretboard but just quickly touching it so that the fundamental vibration is cancelled out. This will make the 2nd harmonic stand out. Voila, you just produced a nice tap harmonic! Some pointers for pulling of the tap in a correct way:
  • The tapping motion should be very quick, only touching the string for a split second at the node. The touch can be a quite forceful slap, as long as it's a swift, short touch, not pressing down on the fretboard. Practice, practice, practice!
  • If you play with a pick (which most of you probably do) your thumb and index are busy holding the pick. You can use your middle finger for the tapping. Do this as follows: stretch out your middle finger so that it points parallel to the direction of the frets, perpendicular to the axis of the neck. Like this, you can (for example) strum an open A chord and tap the 2nd harmonics of the second, third and fourth string at the 14th fret, all at the same time! (see below for video example)
  • Tapping harmonics is a less common technique than pinch harmonics. The tapping technique is used almost exclusively to produce 2nd harmonics, as shown in my video example. If you want a video example of this, I have just recently recorded myself playing Steve Vai's Die To Live which includes tap harmonics, you can check it out here: Steve Vai - Die To Live (YouTube). Another great example is acoustic guitarist Andy McKee, he used some weird ass techniques as well as a couple of tapped harmonics in this amazing song Drifting: Andy McKee - Drifting (YouTube). B. How To Find The Exact Location Of The Nodes? This question has a VERY simple answer: Practice! Experiment! Try pressing a string down behind a certain fret, and then run up and down the string with your pick hand, using the pinch technique to try and find nodes to produce harmonics. (There is more than one node per string, so for every position of the left hand you can produce a number of different harmonics!) If you succeed in finding a node, try and remember the location of it. You will be able to remember a lot of different locations for A little hint for those who don't like to memorise a lot: try to remember certain node locations using orientation points on the body of your guitar. For example, if I fret a string behind the 5th fret on my guitar, the node for the 4th harmonic is located just above the lower edge of my neck pickup. This is of course not the case for every guitar out there, but as I said, experiment! Try to find orientation points of your own, and adjust a little if you are playing a couple of frets lower/higher! C. Artificial Harmonics In Playing: While soloing, you can use pinch harmonics to produce the high-pitched squeals that guitarists like Steve Vai often make. These harmonics can sound really cool if you bend them, use heavy vibrato, or your whammy bar to vary the pitch of the note. You can make your guitar scream with pinch harmonics!

    Conclusion

    Harmonics are truly underestimated by most guitarists, and the reason for this is that most guitarists don't understand what they are. If you listen more closely to Steve Vai records, you will notice that he succeeds in making really cool sounds using only harmonics! Use the potential of your guitar to the maximum and start learning harmonics
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