As a bass player, it is very important to follow the chord progressions. You might think chords are of no value to a bass player, but in fact that is completely false. When a guitarist or a pianist is playing different chords, it is up to the bass player to play the root notes of each chord. This lesson will talk about chord progressions and why we as bass players need to know what they are.
To begin, refresh yourself on scale degrees. Let’s settle into the key of Amajor for the majority of this lesson. The fifth note of an A major scale is E. If we played an E chord in the key of Amaj it would be considered the V chord. Chord progressions are written in the form of roman numerals, like I-V-IV. This I-V-IV (1-5-4) system means that we play the 1st,th, and 4th notes of the major scale. If we play a I-V-IV progression in the key of Amaj, then the chords would be as follows: A(I)-E(V)-D(IV). The A is the first degree of the key (our key is Amaj), the E is the fifth (V) degree of the key, and the D is the fifth degree of the key. So, let’s put this onto the fretboard. 5
We have four measures with four chords each. As a bass player, you play the root notes, or A, E, D, and D again. If you don't already know, music is made up of musical phrases, much like the sentences that we use to converse. If I just kept talking and talking about something over and over and over without taking a break to breathe and just kept talking and talking about information and never ever stopped to breath then my conversations would be quiet boring and lack organization, right? The same applies to music; if you just keep playing random chords and never repeat them, your music will lack organization. Most musical phrases are 4 or 8 bars, and are divisible by 4 or 8. Since our I-V-IV progression only has 3 chords, we repeat the last one to make it a I-V-IV-IV progression. When you only have three roman numerals, it is assumed that you repeat the last one. It is important that you keep the length of your phrases to 4 or 8 bars. This will make it easier to play along with others and help develop your natural feel for music. After some time, you will find yourself “feeling” the music instead of counting it. Now, let’s move on to a minor chord progression.
We have already covered the differences between the major and minor scales. So, if we played the I-V-IV progression over a minor scale, the notes would not change, but the chords might change from major to minor. However, we will just stick to root notes for now. To see the difference in a minor chord change versus a major chord change, we will change our I-V-IV progression to the I-III-V-IV progression. Adding in the III chord will emphasize the minor feel of the minor key. Remember the Roman numerals represent which root note to play in the key. In Am, the progression I-III-V-IV has the notes A, C, E, and D. C is the minor third of the scale. Let’s look at this on fretboard now.
As you can see, the first measure contains the root or I chord, which is an A because the I chord of our key (Am) is an A. The second measure is the III chord or third note of the Am scale, a C. The third measure is an E and the fourth is a D.
If we applied this I-III-V-IV progression to the Amaj key, the third chord would be Db instead of C because we would follow the major scale instead of the minor scale to find our root notes.
If anything in this lesson was unclear or you are having trouble understanding it, you can ask questions in the forums or comment below. Also be sure to watch the video as it may clear up a question if you are a visual learner, like me. Good luck!