So, why does a minor pentatonic work over a major blues?

HAL9000

My musical theory is limited, but I’m guessing it’s something to do with dominant sevenths.

Let’s take a blues in A - chords are A7, D7, and E7..

The minor pentatonic contains  a C which isn’t in the A major scale. However since it’s in the D7 it isn’t entirely unexpected when it does turn up. Ok, so it clashes somewhat with the C# of the A chord but since (blues) solos are often about tension and resolution any such clash can be dealt with, avoided, or even embraced (such as in the ‘Hendrix’ chord).

The minor pentatonic also contains a G which, again, isn’t in the A major scale. However it’s in the A7 so again not  a complete surprise to the ear when it crops up.

Like I say my musical theory is limited - I usually just experiment and find what works. So these are just my musings which hopefully are at least partly right. There’s folk here with far more musical knowledge than I’ll ever have and who can no doubt properly explain why a minor pentatonic works over the major. 

Tannin

Because music theory and blues are not friends.

I could fancy that answer up a bit, and a proper theory expert could fancy it up a lot, but that's the long and the short of it. If you play blues, throw your theory out the window and just play what sounds and feels right.

(PS: and forget any sort of pentatonic scale - you can happily play most (but not all!) of the notes on the fretboard in a blues context.) 

monquixote

Tannin said:

Because music theory and blues are not friends.

I could fancy that answer up a bit, and a proper theory expert could fancy it up a lot, but that's the long and the short of it. If you play blues, throw your theory out the window and just play what sounds and feels right.

(PS: and forget any sort of pentatonic scale - you can happily play most (but not all!) of the notes on the fretboard in a blues context.) 

Basically this. 

Blues is a westernafication of African music which doesn't fit into the western classical music analysis framework properly. 

You will notice for example that when playing the minor third you will probably find yourself bending it slightly sharp to get a mictronal blues third and the same is true of the flat five 

More information here:
https://en.wikipedia.org/wiki/Blue_note

Danny1969

Firstly it doesn't really work  ... if the 1 chord is a major and you hit the flat 3rd over it then it grinds melodically ... that's one of my pet hates is people playing in minor pent over a major key .... if you need to stick to a minor pent shape then play the relative minor .... so F#m pentatonic for A

However in any song in any key you only need to worry about playing over the chord as a passing moment. That's where the melodic phrases come from, hitting the choice 3rds. 5ths and 7th's of the underlying chord as you play over it. 

Take something as simple as Apache (showing my age here I know) It starts with an Am but the 2nd chord is a Dmaj .. so you wouldn't stay in strict Am as that has a natural F and the Dmaj has major third of F#  ....So you always bend the key you are playing to these non diatonic borrowed chords. 

I always say when teaching that if you want to play melodically over any song then first make sure you know all the chords of the song and what the additional qualities are ... such as maj7, add 9 etc 

BillDL

In general you don't dwell on or emphasise the "outside" notes.  You use them as passing notes to somewhere else that sounds less dissonant, or you bend to or through them to reach other notes, or you just hang momentarily on them to create an instability that needs to resolve to something that sounds more settled again. In many ways the "blue" notes are just echoing vocal inflections in music that was rooted in Africa and was influenced in other ways into "gospel" music.  In a way it's not dissimilar to playing a Sus4 chord.  You don't generally stay on that chord.  The note added to make it a Sus4 is normally just used momentarily as an embellishment that hints at the IV chord in the key.  It's not so much the notes that are played, but the manner in which they are played and what notes you emphasise or return to most often as a tonal centre.  Play a pentatonic scale and you can create a semblance of Oriental music by playing it in a certain way, but you can then make it sound like twanging country music by changing the emphasis of certain notes and the cadence.

kelpbeds

If you analyse it, you've got some pretty cool notes there. 1,b3,4,5,b7. 1 and 5 are chord tones over the dominant 7th chord as is the b7 and the b7 isn't in major pentatonic so minor pentatonic has an advantage there.
The 4 is a little offensive but fine as you don't linger on it. But it's that b3 that really has the attitude. You need to bend it a 1/4 tone to make it really work and it gives that blues flavour. When you look at it like that, it's perfect. (Plus you can add in the b5 for more sassy flavour)

LionAquaLooper

I'm not a blues guy per se, so I only heard about this approach on Eric Clapton's "Change The World" -  which isn't even a blues song lol.  But he does exactly this in a short passage in his solo and I thought it sounded cool.  So I tried it and found when done over too many bars, it sounds awful.  So when I use it, it's over just 1 or 2 counts just to add a blues twist or tension to something.  Others above have explained the theory already.  For me it gives that tension but you'd naturally slide/bend to a common note again (root, 4th, 5th) to resolve.             

Roland

LionAquaLooper said:

...  Others above have explained the theory already.  For me it gives that tension but you'd naturally slide/bend to a common note again (root, 4th, 5th) to resolve.             

Guthrie Trapp posted a video yesterday which shows how, in a 1 4 5 blues, the 7th chord is only a semitone away from the next chord you want to play. https://youtu.be/jR39xP-6IyQ

Going back to @HAL9000’s question: It was a revelation to me in my early teens when I realised that the sound I was looking for was the minor scale played over major chords, or to be precise 7th chords. It’s the simplest form of “outside” playing. There is both tension and release in being able to bend or slide between the minor and Mixolydian scales. 

DavidR

Totally agree with Tannin. Anyone who understands pentatonics won’t be able to play the Blues. 

Seriously though, Blues is little more than a chord progression, an attitude and a hard life. Put all that together and you have magic. 

P.S. what the Billy Sheers is Myxolidian?

viz

Theory can still explain the what and the why of the blues though - what it is and why it works. Theory is just explanation. So if it’s explainable, that’s music theory. You probably don’t need words like “chromatic tetrachord”, but theory will give you concepts such as tension and release, flat 7 chords, walking bass, and so on. 

JimmyH

Let's use A Natural Minor (Aeolian)for ease of understanding.

1 2 b3 4 5 b6 b7

This is A B C D E F G 

Minor pentatonic is a reduced version of this consisting of 1 b3 4 5 b7

A C E D G

A Major is 1 2 3 4 5 6 7 only three notes difference to A Natural Minor.

A Major Pentatonic is 1 2 3 5 6

Now if your using Dominant chords which in a I IV V would be

A7 D7 and E7 consisting of

A, C#, E, G
D, F#, A, C
E, G#, B, D

So we have C#, F# and G# which are Major 3rd, Major 6th and Major 7th all of which are the required notes for A Major.

So you can use either Major or Minor pentatonic scales over this progression as well as Mixolydian or perhaps Dorian, I like to use a mixture of Dorian and Blues scale when descending then add some mixolydian notes on the ascent which could be seen as a melodic minor inflection.

You could even change the scale per the chord rather than be static so for instance use A Mixolydian, D Mixolydian and E Mixolydian.

If you wanted to really jazz things up you could substitute the V chord for A# and use the altered scale or whole tone scale.

Point being you can almost justify anything with theory but the real point being does it sound good?

Learn your intervals, learn your scales, learn to construct chords, learn everything you can and absorb as much as possible then forget it all and just play.

jesone

I really wish I could understand this like you guys.

LionAquaLooper

jesone said:

I really wish I could understand this like you guys.

It works for some, not so for others. I'm the type of person who'd rather not know too much theory. It tends to push out other stuff in my brain like wedding anniversaries, kids birthdays etc  

carlos

reposting this

greejn

Just keep blues and 7th based tunes in a different box of theory from everything else!

Barney

I don't think it does work on a major blues iff you hang about on it but us guitarists have got really good at manipulating it and making it fit

Tannin

DavidR said:

Totally agree with Tannin. Anyone who understands pentatonics won’t be able to play the Blues. 

Seriously though, Blues is little more than a chord progression, an attitude and a hard life. Put all that together and you have magic. 

This made me chuckle. (And of course, made me give you the automatic wiz anyone can earn simply by agreeing with me.)

Why the chuckle? Because I don't understand pentatonics and I am unable* to play the blues! 

Oh, I can play the proper notes readily enough, I just don't have the feel of it in my bones. I play a lot of blues-influenced songs, but they never sound like blues, they end up being more like swing or rock or country or even bluegrass. I can sit down and watch one of David Hamburger's excellent fingerstyle blues lessons, learn a few great blues licks, go away and practice them for 10 minutes .... and now I'm not playing blues. They have morphed into something completely different. This happens every single time. 

As for understanding pentatonics, I don't. Not even a little bit. I have never understood what the point of leaving out perfectly good notes is. OK, taken to extremes, that attitude would result in everyone playing the 12-tone scale (which would sound like nothing with any shape or form worth listening to) but take the same notion (i.e., that you leave some notes out of the scale to give the other notes shape and create music with a feel and form) too far the other way and you end up with an over-simplified scale that quickly gets very repetitive and boring. After 50 years of playing I have never yet sat down with a guitar and learned a pentatonic scale, and I daresay I never will. What would be the point? Off the top of my head I can't even remember which notes you have to leave out to make one. 

* Exception: I can play blues if someone else is leading. I could accompany you, @DavidR, and do a reasonable job of it on either rhythm guitar or bass because then I'm in a different mindspace, simply trying to make the singer.or lead player sound good, you are controlling the pacing and the feel - but if I'm setting the pace and you are accompanying me ... the result might be music, and it might even be good music, but it certainly won't be blues. 

BillDL

Pentatonic scales are simply skeleton scales that work over a greater range of underlying chords than a full major or minor scale would.  What notes you choose to add back in and where to add them to flavour the scale is where knowing the chord and scale theory is useful.  It's not essential because most people would eventually find additional notes that worked for certain things, but knowing some of the theory can speed up that discovery process and allow you to explore things you may not have thought about doing.

All this tosh about "good blues players don't need to or shouldn't know theory" is silly nonsense, as is the notion that before you can authentically play the blues you need to have been stabbed by a jealous husband down at the railroad track after your woman left you and you lost your job and possessions resulting in you having to busk barefoot in the snow while drinking cheap liquor from an old soup can.  Yes "blues" needs a particular "feeling", but there are so many different styles of blues-based music that you don't need to sell your soul to the devil or go and live down in the swamp to be able to play bluesy music.

Tannin

BillDL said:

Pentatonic scales are simply skeleton scales that work over a greater range of underlying chords than a full major or minor scale would.  What notes you choose to add back in ...

That'd the best simple summary I've seen. 

guitarjack66

BillDL said:

Pentatonic scales are simply skeleton scales that work over a greater range of underlying chords than a full major or minor scale would.  What notes you choose to add back in and where to add them to flavour the scale is where knowing the chord and scale theory is useful.  It's not essential because most people would eventually find additional notes that worked for certain things, but knowing some of the theory can speed up that discovery process and allow you to explore things you may not have thought about doing.

All this tosh about "good blues players don't need to or shouldn't know theory" is silly nonsense, as is the notion that before you can authentically play the blues you need to have been stabbed by a jealous husband down at the railroad track after your woman left you and you lost your job and possessions resulting in you having to busk barefoot in the snow while drinking cheap liquor from an old soup can.  Yes "blues" needs a particular "feeling", but there are so many different styles of blues-based music that you don't need to sell your soul to the devil or go and live down in the swamp to be able to play bluesy music.

And I sold my mansion for this rat infested shack thinking it was a bargain!

allen

At great risk I'm going to give you some of my thoughts on this.

@JimmyH started it off well although I would take it in a different direction.

So A minor pentatonic has got

A   C  D  E  G
1  b3  4  5  b7

Then the I, IV, V are
A7 D7 and E7 consisting of

A, C#, E, G
D, F#, A, C
E, G#, B, D

So let's see what happens when you hit any note in A minor pentatonic:

A - it's in A7 and D7, but not in E7; however A is the tonic/key of the whole progression so it's okay.

C - it's in D7, but not in A7 or E7; however if you think of playing in position 1 of Am pentatonic your first finger falls on that 3rd string (C) and pulls it slightly sharp in a very satisfying way. In fact, it's so common it's a crucial (cliche) part of the blues style.

D - it's in D7 and E7, but not A7; However, think about that cliche 2 tone bend up from the 7th fret on the g string, goes straight to E (which is in the A chord).

E - it's in A7 and E7, but not D7; Don't know about you, but this only gets played in passing or deliberately during the V turnaround.

G - It's in A7, but not in the others. In position 1, string 2 it gets bent up 2 tones to A all the time. On string 4 it tends to be ghost note just before hammering onto the A.

I think that all of this means that you generally have a 2 out of 3 chance of landing on a chord tone. On top of that you get used to knowing what sounds good where. And finally, if you do land on a bum note a good one is always only one scale step away so it's easy to fix.

I have also just thought about that SRV trill on the major 9th that he does all the time (especially on the V chord) is basically just hitting the 5th of the V7 chord.