By Gary Heimbauer for Guitar Tricks and 30 Day Singer
The pentatonic scale is legendary. It’s learned by every player starting out taking beginner guitar lessons. It’s used extensively by both beginners and world-renowned guitar gods. It’s easy to learn, easy to memorize, and easy to use. It sounds great, and it’s very versatile. But with all that said, as a five-note scale (“penta” meaning five), it’s missing two of the notes of whatever key we’re in (there are seven notes in a key), and those two missing notes can sound so great! For me, it’s often that I HEAR those other notes in my head, but I can’t find them in the pentatonic scale and in my pentatonic repertoire of licks. If you, too, feel like there are some key tones that you can’t seem to find in the pentatonic scale, then that’s the best reason to learn the diatonic scale as your next step. Combining these guitar scales will open up your soloing to a new level. You can always reference a scale finder to help you with this transition.
The minor pentatonic scale contains the following intervals, relative to the tonic of the scale: 1, b3, 4, 5, and b7.
For instance, in A minor pentatonic, these are the notes A(1), C(b3), D(4), E(5), and G(b7).
The diatonic natural minor scale, or the “Aeolian” mode, which is one of the diatonic modes, contains the following intervals, relative to the tonic of the scale: 1, 2, b3, 4, 5, 6, and b7.
For instance, the notes of the A natural minor scale are A(1), B(2), C(b3), D(4), E(5), F(b6), and G(b7).
As you can see, we’ve added a second, and a minor 6th to the pentatonic scale, or in the case of A minor, we added a B, and an F, to give us the diatonic minor scale.
Now over a one chord jam (A minor), you’ll immediately notice the different flavor that we have here. We’ve added two half steps, between the B and C (2 and b3) and the E and F (5 and b6). That’s more of a a diatonic thing — there are no half steps in pentatonic. Pentatonic only has whole steps and minor thirds between each note. The diatonic scale only has half steps and whole steps between each note. These half steps add tension and a different color.
Ok cool! So maybe you do or don’t like the flavor of the A minor diatonic scale over an A minor chord and are still all about your pentatonic licks. After all, the two new notes — scale degree 2 and scale degree b6 are more color tones over an A minor chord. They aren’t fundamental tones. We can also call that scale degree 2 an “add 9” if we add it to to a basic A minor chord. In chord construction, the 2 can be called a 9, the 4 an 11, and the 6 a 13. That’s for another lesson, though.
But where these two extra notes become less “colorful” and more “fundamental” is when we consider other chords in the key of A minor. For instance, If I play the chord D minor, after I play A minor, that’s what we call a i – iv chord progression. In the key of A minor, Am is the i chord, and Dm is the iv chord. Now, on that D minor chord, the minor third of that chord is an F! That minor third is FUNDAMENTAL to the sound of that chord, which means that if you land on an F note over the iv chord, it’s going to have a strong sound that is almost like playing the chord progression in your solo. By landing on different fundamental chord tones, one can almost hear a chord progression in your playing, even if you were playing by yourself with no chords! In the pentatonic scale, you don’t have access to that note F, which is so strong over the iv chord, D minor. Watch my video for a demonstration of how this sounds.
Now this concept holds true for all chords in any key. When you combine the I-IV-V in major or the i-iv-v in minor, you end up with seven different notes, which comprise the diatonic scale of that key. When you combine the notes of all seven chords in a key, you still only have seven different notes – but again, the pentatonic scale is missing two of them!
Now let’s consider the major pentatonic scale. C major pentatonic has the same notes as A minor pentatonic, and C major diatonic (Ionian Mode) has the same notes as A minor diatonic (Aeolian mode).
The major pentatonic scale contains the following intervals in relation to the tonic: 1,2,3,5,6.
In the C major pentatonic scale, this would be the notes C(1), D(2), E(3), G(5) and A(6).
The major diatonic scale contains the following intervals in relation to the tonic: 1,2,3,4,5,6,7.
In the C major diatonic scale, this would be the notes C(1), D(2), E(3), F(4), G(5), A(6), and B(7).
As you can see, it’s the same exact notes as the A minor pentatonic and diatonic, but each note is now re-contextualized relative to a new tonic or starting note, so the intervals are completely different.
The two notes missing from the major pentatonic that are in the diatonic are a 4th (F) and a major 7th (B).
Now right off the bat, the sound of a major seventh over a one-chord C jam is such a jazzy sound — I couldn’t imagine not having that at my fingertips. But again, if we consider an actual chord progression like C – F – G (I-IV-V), we again have all seven notes represented in the combined triads of those three chords.
The B is the major third of the G chord – a VERY fundamental sound to that chord. The F is the ROOT of the F chord, which of course, is a VERY fundamental sound to that chord.
I hope you can now see and hear how the pentatonic scale is fundamentally lacking over very basic chord progressions in terms of really locking in with the different guitar chords. Now, I’m not saying that you have to be consciously aware of the function of each one of these notes and which note is a chord tone over which chord. However, if you have the sound and the shapes of the diatonic scale in your head, you will naturally gravitate to the fundamental tones over each chord when you hear that chord or anticipate its arrival. Each chord has a gravity that will pull your improvisation or composition toward certain notes, provided you are listening, and you have those notes under your fingers!
In time, you’ll develop a more active awareness of what you are doing and what you aim to do from a structural standpoint, but that’s not necessary to begin to hit these fundamental tones just because you like the sound of it. But if you don’t know the scale and you don’t have those notes under your fingers, you won’t find them. Of course, you can abandon the idea of any scale framework completely, which puts all the notes at your fingertips at any time- but most people will agree that scale training (which is also ear training) is a necessary step to then being able to forget the scale completely. You can eventually learn it so well that you can then forget about it!
If you want to see everything I just explained with actual playing examples, check out the video here: