Understanding Intervals Part 3 – Fourths

Hey, Happy Post Thanksgiving…

Now that we’re done over eating, lets work off some of those calories with some music!

So far we talked about major and minor seconds, and then major and minor thirds. Now come Perfect Fourths.

“Why are they perfect” you may be wondering….

Ok, I’m going to try to make this brief and not boring. If you’re interested in researching this information in depth, there is a wealth of information out there you can google.

Musicians experimented with different tuning systems over the ages. Each system had it’s trade offs. There was “well temperaments” which was replaced in western music by the “equal temperament” or “Tempered Scale”. In a way, equal temperament was a compromise between the other systems. Neither the third nor the fifth is pure, but neither of them is terribly far off, either. Because equal temperament divides the octave into twelve equal semi-tones (half steps), the frequency ratio of each semi-tone is the twelfth root of 2.

I warned you it was complicated!!

I still haven’t answered the question why the Fourth is considered perfect. Notes of a perfect interval are very closely related to each other and sound very pleasant together. When you play a 2nd or a 3rd, you hear vibration. 4ths have very little vibration between them.

As a side note – the Tempered Scale isn’t perfect, something your guitar technician will sigh and tell you when you complain about your intonation (how in tune the guitar is as you go up the neck). He or she can come close with your instrument, but it will never be perfect.

Let’s get back to playing!

Let’s take the key of G:

1 2 3 4 5 6 7 8 9 10
G A B C D E F# G A B

Notice I continued through the number system. This is to help you to see the 4ths as we go through the Key of G.

So as we pair our 4ths in the key of G, we get:

C F#
F# B

So a perfect 4th is 5 half steps up from your starting note.

All these intervals, as they lie in the key of G, are perfect except one. C to F# is not perfect, it is made of 6 half steps (or 3 whole steps) and is called an augmented fourth. It has a hash sound.

Perfect intervals are neither major or minor. If they are raised a half step, they are augmented. If they are lowered a half step they are diminished.

The augmented fourth and the diminished fifth (you’ll see in the next entry that fifths are perfect too) are, in fact, the same note. Three whole steps from their starting point. This is also called a “tri-tone” and is one of the harshest intervals we have in our equal tempered system. In fact, lore has it that at one point it was considered the devil’s interval and people could be put to death for playing it. (In today’s world, we call that a “tough audience”).

But do not dismiss the tri-tone so quickly. It has a place in music and is, in fact, in all our dominant 7th chords.

Let’s start to apply this.

Fourths lay easily on the guitar. Between all strings except 3rd and 2nd, the fourths lie on the same fret. So 6th string 3rd fret is G, 5th string 3rd fret is a C. You can play them together as “double stops” since they sound well together or individually. The augmented 4th will be one fret off – 7th fret 6th string to 8th fret 5th string.

The third and second string perfect fourth are a fret off from each other. 2nd fret 3rd string to 3rd fret 2nd string. These sound nice in the upper strings and I usually play them together.

Another way to play them is in groups of 3’s:

Finger Fret String
1 5 6
2 5 5
3 5 4

1 5 5 (note here we doubled back to the 2nd note in the series)
2 5 4
3 5 3

1 5 4
2 5 3
4 7 2 (this is the tri tone interval as it lies in the key of G)

1 5 3
2 7 2
3 7 1

Now descend with it:

Finger Fret String
3 7 1
2 7 2
1 5 3

4 7 2
2 5 3
1 5 4

3 5 3
2 5 4
1 5 5

3 5 4
2 5 5
1 5 6

This is just one area of the neck. You should experiment around with this and learn your fourths (as you’ve learned your thirds) through the major scales. Perfect fourths also lay well in pentatonic blues scales too.

A blues lick using 4ths:

Finger Fret String
1 7 3 \
2 8 2 / play these together and slide up a whole step to 9th/10th frets

Finger Fret String
1 12 3 \
2 13 2 / play these together

Finger Fret String
1 9 3 \
2 10 2 / play these together – this is an ‘A’ sound for A blues

These are just a few things for you to play around with. Have fun…

Spencer Out

Understanding Intervals Part 2 – Thirds

Hey Shredders,

Last blog I brought up the subject of intervals and we had some fun looking at seconds – both major and minor, and how they can break up your playing patterns by exploring that interval.

Today we’ll be looking at thirds. Thirds can also be major or minor. Minor thirds are 3 half steps, major thirds are 4 half steps.

One important factor is that chords are built in thirds. Read that sentence again. If you still look at a chord as a mystery group of notes, this is the time to get past that. A major chord is build of 2 intervals of a third – a major third and a minor third.

Let’s look at the key of G:

G A B C D E F#

G major chord: G B D

G to B is 4 half steps, it is a major third. B to D is a minor third as it is 3 half steps. Every major chord has the same structure. Now they don’t have to be played that way – you can mix the notes up anyway you want and double them. But play your favorite position G major chord and write the notes down in that chord. You’ll find that chord only contains those notes and some are repeated.

Different chord positions are called “voicings” and will be the subject of a different blog entry.

To make G major a minor chord, you have to change the thirds…meaning the first third needs to be minor, the second third needs to be major:

G Bb D

G to Bb is now 3 half steps while Bb to D is a major third.

Ok, so much for chord theory. How can we incorporate this into our playing? A few ways:

1) Double leads. Most double guitar leads you hear are in thirds. So if Bob is playing

Chuck is playing


Instant harmony.

2) “Double Stops” – double stops are just playing to notes together on two different strings. A major third on most stings is the bottom string is on fret X, the next string up is on fret X-1. (X being the fret you pick). A minor third is X on bottom and X-2 on the next string.

So 6th string 5th fret and 5th string 4th fret is a major third built off of A.

(Note: bottom refers to pitch on the instrument, not the phsyical location)

Now the 3rd and 2nd strings are different. Major thirds lie on the same fret for these two strings, while the minor third is X and X-1.

So 5th fret 3rd string and 5th fret 2nd string is a major 3rd built off C while a 5th fret 3rd string and a 4th fret 2nd string is a minor third off of C.

To really get an idea of where you want to play with thirds, this lends itself really well with major scale work, although it can be applied to rock and blues as well, but there are more rules to that and I want to keep it simple.

3) Play thirds on single strings. If you know your major scales, just play the first finger note and the 4th finger note on the same string- that’s a third. (I’m taking about the 3 notes per string major scales, NOT the classical scales).

I want to play a game…..

Practice playing your major scales like this. For example, G major first position:

String Fret
6 3
6 7
5 3
5 7
4 4
4 7
3 4
3 7
2 5
2 8
2 5
2 8

Play this ascending and descding. Trill them.

4) In your major scale, play every other note. Note only does this sound cool but you’ll be able to travel a farther distance faster on the guitar. Practice ascending and descending.

Next, learn the thirds in this same scale on two strings. So play 6th string 3rd and 5th string 2nd together, then 6th string 5th and 5th string 3rd and continue to go up those same strings

7th fret (6) 5th fret (5)

9th fret (6) 7th fret (5)

10 fret (6) 9th fret (5)

And so on. Play them together like a mini chord. Learning them on all the strings will take some work and remember, they lay differently on the third and second string.

This just scratched the surface of what you can do with thirds. Triads and apreggios use thirds as well.


Rock on,


Understanding Intervals Part 1

Hey Shredders,

An interval is a distance between two notes.  The shortest distance you can travel on the guitar (excluding bending) is one fret.  That is a half step.  And is a minor second.  A whole step is two frets on the guitar and is a major second.
Any Diatonic scale like major and minor scales are made up of seconds, both major and minor, as well as the diminished scale.  The Whole Tone scale is made up of entirely whole steps (play it, it sounds kinda spacey!) and the Chromatic scale is made up of all half steps.
Note that the Pentatonic and blues scales have larger intervals in them at points.
The next time you go to practice improvising, pick a chord progression that you can play some major scales to, like a ii V in G (Amin7 D7).  
And now, as they say in the movie Saw, “I want to play a game”, but this won’t be gruesome…
Pretend you are limited to either major or minor seconds on each string.  that means if you play an A, you can go to G or B.  Then switch strings.  Never mind that when you switch strings you will be jumping a larger interval.  We’re thinking “Seconds on Single Strings” only.
So you play A to B on the 6th, then D to E on the 5th, then G to A on the 4th and so forth.  In fact, you can play 5th fret to 7th fret on each string and stay in the key of G.  You can make box shapes out of them.  Try skipping strings.  Try 5th fret to 7th fret on the 3rd string, and then 5th fret to 7th fret on the 1st string.
You can play these seconds by picking them, trilling them (fast hammer on/pull off) or bending or sliding.  You can whammy bar bend them.  Just keep it to seconds.
Obviously, this is visual game on the guitar.  But look at what we just did – we broke you out of your old habits.  You’re playing like you never would before.
Try this one.  Use all trills:
1st string frets 14 and 15
2nd string frets 12 and 13
3rd string frets 11 and 12
4th string frets 9 and 10
5th string frets 7 and 9
6th string frets 5 and 7
Try the reverse and ascend.
To recap, the interval of a second is either minor (half step) or major (whole step) and by playing a visual game on the fret board you can focus on that interval and come up with new sounds and shapes.  In contrast to what we may think, we get creative with limitations.  When we are blocked this way, we learn to get creative in others and this pushes us to think in different ways.
Rock on,