What is an Octave?
An octave is the same note at a higher or lower pitch. You'll recall from the musical alphabet lesson there are only 12 notes in music. That same cycle of 12 notes is repeated over and over in what are called different octaves. That means there are multiple 'A' notes, multiple 'Bb' notes, and so on. Each one is just a higher-, or lower-pitched version of the others.
The Same but Different
The idea of octaves can be confusing at first. How can it be the same note when it sounds different? The simplest answer is octaves ring similarly. If you play them at the same time, you will hear how they sound very consonant with one another. The more technical answer (feel free to skip this) is the octave of a note is either half or double the frequency of the note. The note 'A' rings at 440Hz; 'A' an octave lower rings at 220Hz; an 'A' an octave higher rings at 880Hz.
Playing Octaves on the Bass
The most common way bassists play octaves on the bass is: from any one note the higher octave can be played two strings up and two frets over. This octave pattern exists on any fret of any string of the bass so long as you don't run out of strings.
To get any note's lower octave, reverse the pattern: play the note two strings down and two frets back.
This pattern also works for open strings. You can see the octaves of open E and open A in the interactive fretboard diagram.
Fingering Octaves on the Bass
Click the Play button on the fretboard diagrams to see the suggested fingerings and hear the notes.
Sticking to the one-finger-per-fret rule would mean you play the low note with finger 1 and the higher octave with finger 3. You should be able to do this. It's also okay to break the one-finger-per-fret "rule" and play with your 1st and 4th fingers. This is more comfortable and makes it easier when you are playing a lot of octaves. Practice it both ways.
When you play and practice octaves, don't let them ring together at the same time. Instead, use a see-saw rocking motion to play the octave notes individually where only one note is ringing at a time. It's not that you can never play octaves at the same time. It's common to do so. But, playing them independently takes a little more work and is more common.
Other Octave Patterns on Bass
Remember, octaves aren't a finger pattern, but a pattern of sound. There are many more ways to play octaves on the bass. You can play the octave of any note 12 frets higher on the same string. You can also play a higher octave of a note 7 frets higher on the next string as shown in the Open D-string example.
Using Octaves in Bass Playing
The use of octaves in basslines is very popular. A lot of times a bassist needs to keep the notes simple. For instance, a bassline might only call for root notes. To add some variety without adding more notes to the mix, we could add in octaves of those root notes.
You will find that octaves are used in all styles of bass playing and styles of music. Some of the most obvious places you can hear octaves are in slap basslines and in disco basslines. But, as I said, octaves are used in everything under the sun.
The Sound of the Octave
As you start learning different note patterns on bass and in music in general, you should try to absorb the sound of the pattern. You want to learn to recognize these sounds when you hear them. This takes time. A good first step is to relate it to something familiar like a well-known melody or bassline. Learn to sing or hum the pattern.
You can think of these sounds to get the sound of the octave in your head:
- the first two notes of the melody to Somewhere Over the Rainbow (Some....where...)
- the bassline of the intro to Jimi Hendrix's Purple Haze (root-octave-root-octave)
- the main riff to My Sharona by The Knack (root-root-octave-octave...)
Try out the octave exercises and octave examples.