This is a guitar lesson that will teach you just what the title says, how to play octave intervals on the guitar. But first - just in case you're not sure what an octave is - it starts with a very brief theory interlude. Scroll straight down to the second section right now if the word "theory" makes your eyes go all swimmy.
What's an Octave?
Remember the Do Re Mi song? I hope you do. Well when you get to the bit that goes "That will bring us back to do" that's an octave. You've climbed up all seven notes of the major scale and land back on the eighth note with the same name as the starting note. The fancy name of this interval "octave" is derived from the Latin word for eight.
When you play that same note twice in two different registers it gives the note a thicker and richer sound that some people find quite tasty. This technique is used in some solos and in rhythm guitar.
The distance from the starting note to the octave is twelve semi-tones. Those twelve semi-tones rather conveniently correspond to twelve frets on the guitar neck. So, for example, the E note on the open sixth string has an octave at the 12 fret of the same string.
But despite the convenience for our minds it is obviously quite impossible to play these two notes at the same time. Even if you have an improbably huge finger stretch you can't play two notes at once on a single string. Luckily for us guitar players though the octave interval of any note also occurs on different strings, and with a far shorter finger stretch to boot.
Octave shape on the sixth and fifth guitar strings
Because the guitar's tuning has a different interval between the 3rd and 2nd pair of strings than the other pairs there are two slightly different fingerings to learn. We'll start with the shape you use when the bottom note is on either the 6th or the 5th string, shown in the diagram below. The octave interval occurs two strings below the starting note and two frets higher up the neck.
You can move this shape along the 6th or 5th string to play any octave. To play a G octave, for example, there are two fingerings that start on the 5th and 6th strings:
- Low G at the 3rd fret of the 6th string with high G at the 5th fret of the 4th string
- Low G at the 10th fret of the 5th string with high G at the 12th fret of the 3rd string
Move these two positions up two frets and you play an A octave, two more frets a B, and so on.
Finger the low note with your first finger and the high note with your third (ring) finger. Keep your first finger low so it touches the "in between" string lightly to mute it so it doesn't sound as you strum.
Octave shape on the fourth and third guitar strings
When you play the starting note on the 4th or the 3rd string the octave is still two strings below but it is now three frets up the neck from the starting note.
Going back to our example G octave you can play it at these two places:
- Low G at the 5th fret of the 4th string with high G at the 7th fret of the 2nd string
- Low G at the 12th fret of the 3rd string with high G at the 15th fret of the 1st string
Again, use your first finger to play the lower note, but you'll probably find it's more convenient to play the higher note with the little (pinky) finger. It makes the three-fret stretch easier. If you move up the neck beyond the 12th fret you might find it becomes easier to use the third finger to hold the higher note of the interval. Experiment a little to discover what feels best to you.
Three easy steps to find any octave
This lesson has shown the two shapes commonly used to play octave intervals on the guitar. Remember these three easy rules to find the octave interval of any note on the third, fourth, fifth or sixth strings:
1. The octave is always two strings below the starting note
2. Move two frets up the neck for starting notes on the 6th or 5th strings
3. Move three frets up the neck for starting notes on the 4th or 3rd strings
But can you play octaves on the 2nd string?
You might be wondering if you can play octaves from a starting note on the 2nd string. The answer is yes, but I don't know of anybody that does it because of the huge finger stretch required.
Obviously, you won't find it two strings below as there are no more strings down there. Instead, you'll find it on the string below - the 1st string - and seven frets up from the starting note. But don't worry if your fingers won't stretch this far - the shapes above should suffice.