Pentatonics are among the most widely used scales. They are present in many genres of music and are very powerful.
First, let's step back a bit. Let us look at arpeggios. Arpeggios are the notes of a chord played one at a time. See my previous blog post onArpeggios for more info. Playing these over chords gives complete tonal backing of the harmony. However, there comes a time or a place when one wants to go beyond chord tones. Anything beyond a chord tone can be considered a "color" tone. Color tones can be very useful when making basslines. However, one player's color tone is another's clashing tone. So, the pentatonic scales contain color tones also used by chordal instruments.
Major chords can be "colored" by adding the 9th and 13th tones of the major scale to the triad. By lowering these notes down an octave to fit in the scale, they become the 2nd and 6th.
Therefore, the major pentatonic is defined as the root, 2nd, 3rd, 5th and 6th (e.g. Key of C: C-D-E-G-A)
The minor chord is affected similarly by adding the 11th and b7. The 11th is brought down an octave to be the 4th and the b7 is left unchanged. Hence, the minor pentatonic is defined as root, b3rd, 4th, 5th and b7 (e.g. Key of C: C-Eb-F-G-Bb)
You probably know these scales or have at least played then in one form or another. The best way to think of them, in my opinion, is as arpeggios with color tones...these color tones allow for melodic movement between the chord tones and can add interest to basslines or improvisations.
Pentatonics, like all scales, are just NOTES. Not a pattern or series of patterns. If you play them as patterns, you will sound redundant and play "the same old stuff" again and again. The only real way to unlock the power of these scales is to know them as notes and apply then as notes...in your ear, your brain and under your fingers. Learning the role of each tone of the scale when played over chords will unlock so many ideas. You will see why they are so powerful.
Once you are familiar with the pentatonics, a good exercise to begin to apply them is to choose a chord progression. For example this 8 bar phrase:
|Gm|Gm|C |D |Gm|Gm|D |D |
Play over it with a metronome first as roots only with a groove (any groove you like), then with roots and 5ths, arpeggios and finally pentatonics. Make a backing track with the chords or have a friend play them if possible. Listen to how the different degrees of harmony change the bassline. It is those "changes" that will add interest to them and increase your ability to make original music.
Eventually, you can move on to more advanced subjects like relative minor and blues harmony. These will be covered in later installments.
Lots of luck. Keep practicing. Message me with questions.