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Since there are three pentatonic scales that work with any diatonic chord progression, how do you decide which one to use? If I have a chord progression in Bm, I could use Bmin, Emin or F#min pentatonic scales and all the notes will be found in the Bminor scale. What are the differences between those 3 pentatonic scales and why would you use one over another?

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  • What are the 3 ? I am confused. Please provide examples in terms of notes or patterns on a guitar.
    – user50691
    Jul 15, 2020 at 23:56
  • @ggcg - The 3 scales given are the Bmin, Emin, and F#min pentatonic scales for a B Minor piece. These are the minor pentatonic scales built on the tonic, subdominant, and dominant, respectively.
    – Dekkadeci
    Jul 16, 2020 at 12:00
  • That was not clear from the context. That seems to imply that there is not a C pentatonic for example. And the statement is still incomplete because in this context there are 6 pentatonic scales that work on any diatonic progression, three maj and three min. I was under the impression that the OP was referring to generalizations rather than specifics.
    – user50691
    Jul 16, 2020 at 13:00

7 Answers 7

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I advice you to learn about modal scales and what modal scales fit what chord progressions. There are many resources about that, in particular in jazz music handbooks. Then you can think of the pentatonic as a subset of notes in the scale. You will understand which characteristic notes from the modal scales are present in given pentatonic, and which are omitted.

In particular, in key of Bm

  • Bm pentatonic (b d e f# a) is a subset of B aeolian (b c# d e f# g a), dorian (b c# d e f# g# a) or phrygian (b c d e f# g a) scale
  • Em pentatonic is a subset of B aeolian or phrygian scale (so may not work as a substitute for dorian)
  • F#m pentatonic is a subset of B aeolian or dorian scale

...and there is one more! Less commonly known for its a bit more exotic sound:

  • C#m pentatonic is a subset of B dorian scale
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  • I agree. The pentatonic scales are simply reductions of modal scales. Learn the modal scales, and you have it all at your hands! Jul 15, 2020 at 22:21
  • It could be argued that this not how the pentatonic scales were developed historically, but probably the best way to understand them today in the context of chords and harmony. Jul 15, 2020 at 22:54
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Why would you use one [pentatonic scale] over another?

Each pentatonic scale has a tonal center — a pitch toward which the others are directed. That's how the letter-name part of the scale is derived. So you would either pick a pentatonic scale that has its tonal center in common with the chord you're playing over (say, B minor pentatonic over a B minor chord), or you might choose to play against the chord by choosing a pentatonic that has a contrasting tonal center or perhaps other notes that present dissonances against the bass (say, E major/C# minor pentatonic against a B minor chord).

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  • I believe this answer is misleading. What we normally mean by "playing E minor pentatonic over Bm chord" is to play the notes of E minor pentatonic, but with the tonal center at B. You can call it a different mode of the scale. Unless you play polytonal music (weird stuff) you don't want to have two different tonal centers coexist. Jul 16, 2020 at 14:58
  • I think this is the only answer that contains a very important point, namely the mention of tonal center and directing the music towards a pitch. As far as I can see, the other answers just concentrate on the set-of-notes aspect of a scale, i.e. what notes are found or missing in the scale etc. BUT the relations, intervals between the notes in major/minor pentatonic scales, AND the lines or "licks" that are usually played with the scales are such that the lines tend to point at certain pitches... It's too long to explain in a comment. :/ But if I add an answer, it may feel like off topic. Jun 5, 2022 at 15:23
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Here's a web page where you can enter a chord progression and it will show you which parent scales may be used over one or more chords.

http://www.micrologus.com/tools/online_harmonic_analyzer

You can then use major pentatonic scales instead of regular major scales, and minor pentatonic scales instead of regular minor scales.

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As @user1079505 already commented, the minor pentatonic scale contains all the notes that are common to the minor modes (aeolian, dorian, phrygian). So it all depends on the context (that is, the exact chord progression).

Normally, if you're playing over a progression in Bm, you would play the Bm pentatonic. Regardless of whether your progression is Bm aeolian, phrygian or dorian, the Bm pentatonic would be a good match. Also, you will find that the other 2 scales you mention lack important tones (the minor 3rd in the case of F#m and the 5th in the case of the Em).

You could just stick to the Bm pentatonic, and it would be "fine". However, I would argue that it is not enough. You will get more variety in your sound if you add some extra notes. In particular, the 2nd and the 6th, which are the notes missing from the pentationic. These 2 will depend on the other chords in your progression, and will determine what mode you're in.

Also, bear in mind what @Tim said about the V chord. That's an issue you will find when playing in minor modes, whereby you will have to get out of the strict mode, and weave into the harmonic minor scale when you're playing over that one.

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There are 2 common pentatonic scales, the major and the minor. Using the major scale degrees as a reference (1, 2, 3, 4, 5, 6, 7), the Major pent is (1, 2, 3, 5, 6) and the minor pent is (1, b3, 4, 5, b7). I am not sure of a third but in fact you can create your own 5 notes scales (or 6, or 13 note, ;-)) but removing, adding, altering notes to Do-Re-Mi... so I might "know" other 5 notes scales but don't recall them as "Pentatonic".

You can, for example, play the either of these two 5 note scales starting on another note other than the "1". This generates alternate fingering patterns on the guitar which I, and most guitarists, are aware of. But in fact, if you play the Major pentatonic starting on the last note (the 6) you will be playing the minor pent. This is related to the fact the the relative minor scale of any major scale starts on the 6th degree. FOr example C major pentatonic and A minor pentatonic are the same scale in a sense (same set of notes).

The great value of the 5 note scale has been stated by other answers but bears repeating. Namely, that there are three related major modes, Ionian, Lydian, and Mixolydian, and three minor modes, Dorian, Phrygian, and aeolean. The notes are, respectively,

(1, 2, 3, 4, 5, 6, 7) = Ionian (major)

(1, 2, 3, #4, 5, 6, 7) = Lydian

(1, 2, 3, 4, 5, 6, b7) = Mixolydian

(1, 2, b3, 4, 5, 6, b7) = Dorian

(1, b2, b3, 4, 5, b6, b7) = Phygian

(1, 2, b3, 4, 5, b6, b7) = Aeolean (minor)

The petantonics cover the "common" notes among these sets. When choosing a scale to play over a set of chords it helps to be able to analyze the progression to identify a common key, or notate key changes. Since all these modes are related if you know one you know them all. But a short rule of thumb is play the minor pent over minor chords and major pent over major chords. If all these chords are in the same basic key then matching to the first chord would suffice. You'll have to use your ear to hit the "right notes at the right time".

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  • It's quite common to play the pent. min. scale notes over a major (or dom. 7th) set of chords - Blues is often played in this way.
    – Tim
    Jul 16, 2020 at 9:36
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    I know. But the context of the question didn't lead in that direction.
    – user50691
    Jul 16, 2020 at 12:57
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If I have a chord progression in Bm, I could use Bmin, Emin or F#min pentatonic scales and all the notes will be found in the Bminor scale. What are the differences between those 3 pentatonic scales and why would you use one over another?

The differences between scales are in what you can do and cannot do with them harmonically. And what you tend to do in practice.

Can-do and cannot-do

Limiting your note palette limits what combinations you can create against the backing chords. But there's another dimension - what harmonic implications your lines have in themselves. If you're playing a solo, you're drawing attention to the solo notes as a separate stand-alone entity, and if you play strongly, you have a possibility of diverting the whole harmonic interpretation away from the backing chords.

Let's take a basic phenomenon: the roles of intervals in triads. In C-E-G or C-Eb-G, regardless of how you order the notes, the C+G pair points to C as being a root. This happens whenever you have an interval of a fourth or a fifth. If it's a fourth like in G-C, the upper note feels like a root, and if it's a fifth like in C-G, the lower note feels like a root. For example, you can play "power chords" as either fourths or fifths. "Smoke on the Water" uses fourths - the "melody note" is the higher note of every power chord. (If there are multiple fifths and/or fourths in a chord, then it's more complicated but let's talk about the simple case.)

You don't have to play the notes simultaneously. You can arpeggiate or include them in a melody line - if the notes are positioned rhythmically in a certain way, the same pointing-at-root phenomenon occurs. No matter how you alternate between C and G, the ear gets the idea that C is a center pitch of some kind. If there's already a different strongly established tonic, then C is felt only as a non-tonic chord root.

When you select a pentatonic scale, you also select a set of fourths and fifths, i.e. the possible chord roots you can imply.

Let's say you have the following five notes: A, C, D, E, G. What fourths or fifths can we get out of those, i.e. what roots can we point at? We can point at:

  • C+G or G+C -> C
  • A+E or E+A -> A
  • A+D or D+A -> D
  • D+G or G+D -> G

If there are other instruments playing in your "backing track", you can include notes from the base scale, e.g. the root note of the sounding chord, in the equation, and then you get more possibilities for looking at the "what could I do with these notes". I won't try to list examples, because the list gets very long very quickly. But I hope you get the idea.

There are of course other important "can do" notes to consider. For example, if you select F# minor pentatonic, then you cannot emphasize D, the third of a Bm chord. If you want to make sure that you don't emphasize a Bm tonic chord in a too simplistic way, choose F# minor pentatonic as your scale. Then you'll be making the harmony feel less like having reached an expected ending.

What you tend to do

Like we know from so many questions about "what's the difference between modes, if their scales contain exactly the same notes", it's not what you use (the notes), it's how you use the notes. And here we come to rhythmic emphasis and phrases you build from the notes.

Some people, particularly beginning guitarists, use scales for playing notes in a completely randomly order, in random places, without phrasing or relation to the backing notes. That's just random rubbish, note salad, noise.

But let's say you don't play random note noise, you've practiced pentatonic phrases and licks. Most phrases that people care to practice, make sense harmonically, and they tend to point at certain notes as possible roots or tonics. Especially the tonic note of the scale. If your line constructed from the A-C-D-E-G note set seems to point at C as being the tonic, then I would say that it's a lick using the C major pentatonic scale, even if you thought you used the A minor pentatonic scale.

When you select a pentatonic scale to use, since you've practiced phrases and licks so much, you then tend to point at the notes that those phrases and licks point at.

You don't have to stay diatonic

Your question implies - not strongly but anyway - that the only possible choices of pentatonic scales over a progression in B minor would be B minor, E minor and F# minor. But that's not true at all. You don't have to stay diatonic! Since pentatonic licks often have such a strong tonic-implying characteristic, they are used a lot by jazz soloists to sound "outside" and to move the harmony in non-diatonic ways by playing solo lines. As a simple example, if your song is in C major, and there's a C major chord, you can play G minor or Bb major pentatonic licks, in order to make it sound like a Bb/C or C7 dominant chord. Or you can move your pentatonic lines chromatically all over the place, to just play outside.

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If you know there are 3 pents that work over Bm, then you will know what their differences are.

It is pretty well dependent on what chord is prevalent in each bar. You can say there will be bars of Bm, Em and F♯m. There may also be bars of D, G and A, over which those 3 pents will work respectively - they're the relatives, after all.

A lot of players - especially beginners - will use Bm pent exclusively, but that means occasionally there will be 'avoid notes'. Not using them means everything sounds as it should - no clashes.

The fly in the ointment can be V - F♯. Often in Bm, the V is F♯ MAJOR, not minor, so F♯ min pent may be more difficult to make fit.

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