Is a Blues in A really in A?

Shane, this is all good brain fodder.

My initial thoughts.

The dominant 7 chords of A7, D7 and E7 all contain the most unstable of intervals, the dissonant tritone. This interval is found between the major 3rd and the flat 7th of each of the chords. These are the very two notes that make up the small chord fragments shown by Perfecto de Castro in Step 3, from 3min 25sec of the video. He calls these ‘the secret to the blues’. Those two notes are ‘wrong’ together. But hey, they’re also not wrong.

Everything after Step 3 is embellishment that is built on the core foundation of the ‘secret to the blues’.

I think Perfecto correctly describes them as ‘colour’ notes. Often, we would use the word tension to describe the sound, but tension tends to need to be partnered with resolution in music. Because all chords are dominant 7, there is no resolution in that sense. The tritones add flavour and texture and character to what would otherwise be plain old I, IV and V major chords.

Another perspective. By way of analogy.
Here is a diatonic chord progression. Every chord belongs within the key of G major.

Here is a progression based on the one above but with the inclusion of some borrowed chords.

The progression has been modified and is no longer wholly diatonic. The two chords that are out-of-key are Bb and Eb. They have been borrowed from the parallel minor key of G minor. They add a surprise spice within the overall taste of G major. The appearance of those two chords would not cause us to look and analyse and describe it as a modulation to a different key. We remain within the key of G major but we have allowed some non-diatonic friends to join the party and dance with us.

A similar view could be applied to the non-diatonic notes that are welcomed into the major blues party.

The A major scale
A, B, C#, D, E, F#, G#

The A7 chord
A, C#, E, G

The D7 chord
D, F#, A, C

The E7 chord
E, G#, B, D

Both A7 and D7 contain one note that is non-diatonic. If we were being super strict and unbending in our application of the ‘rules’ then we would have to conclude that we have chords that do not belong to the key of A.

However, a more generous approach is to allow their inclusion and welcome them to the blues party. Their attachment to what would otherwise be diatonic triads does not necessarily push A7 or D7 away from remaining diatonic to the key of A. It merely means that those two chords are enhanced by an exotic spice. The chords are not being dragged out of key, they are simply dancing with an unexpected party guest.


We dont need to agree on anything. :slight_smile: This thread started as a theory discussion, there are people who enjoy that stuff. whether it helps with playing or ruins creativity everyone will have to decide for himself.

1 Like

Some interesting input here so far.

Seems to be a general theme here regarding theory vs playing, as if they were somehow sworn enemies that exist in different realities.
I’ve never understood, nor have I yet been confronted with any valid reasoning, or rationale, behind this type of thinking.
It seems to me one of those catchcry phrases that has no real meaning to it.

I’ve only been at this business a few short years, but I’ve always seen theory as a very practical endeavour that has always informed and assisted my playing. Never has it been any enemy of my creativity, but rather a powerful ally.
It is the way Justin introduced me to it in his brilliant PMT course, and I thank him for that.

Cheers, Shane


Yes, I see your point, and I agree, you could just as easily see them as borrowed chords, or added ‘spice’ from ‘outside’ notes, while essentially remaining ‘in key’.

I suppose my main angle was that these V7 chords belonging diatonically to 3 different keys opens up a whole new area of harmony, movement etc between the chords.
It gives potentially 21 dyads,triads, quadads etc to play around with and create diatonic harmonies relative to the ‘parent keys’.
eg jazzy ii-V-I arpeggios, or vii-I-ii dyads

Cheers, Shane


I might just go back and have a closer look at those two notes… :wink:

Don’t do that to me!
I thought I had to back to square one :open_mouth:


Typo corrected thanks Brian.

1 Like

If you want to hear the tritone laid bare and pressed home with brute force, right between your eyes

I see your point. And the possibilities are endless. It really does take you along the path from blues to jazz.
One example, you could expand the chordal progression so that each is arrived at using their own 2, 5, 1. That would be ‘tonicising’ the three chords in their own right.

Moving to A7 with a 2, 5, 1 (A7 is tonic already)
Bm → E7 → A7

Moving to the D7 with 2, 5, 1
Em → A7 → D7

Moving to the E7 with 2, 5, 1
F#m → B7 → D7

From memory, I haven’t watched it again before making this post, I think Josh Smith talks about 2, 5, 1 in blues in this interview with Justin.

Yep, this is exactly what I mean. And similar with say, using vii-I-ii doublestops with these tonicised V7 chords.

I wasn’t implying that theory was the enemy of creativity rather I was doubting my ability to apply it in an improv. For example, when Joe Pass improvised over a jazz chord progression, that could change chord each bar even half a bar or even on every beat, did he have time to think “I need to pick notes from this or that arpeggio”. Now maybe he did or maybe it became intuitive with practice. Eitherway I doubt my ability to think like that. Maybe @Richard_close2u could advise if this can be developed.

On that I am of little help Rory. I’m not a jazz fan, have never spent time learning its intricacies and that incredible technical / musical fluency and dexterity is beyond me.

1 Like

I bet he first endlesly played the progression and knew it inside out and inside again, then thought/practiced/reflected/listened to everything he could play over it, then played it a zillion times picking favorite sounds over passages of certain form, then was able to pull it off “effortlesly” when needed. The effort (A LOT OF IT) comes when no one is looking/listening. My view anyway. Try improvising over blues without learning any lick, by theory or by feel. Then learn and practice 100 licks for a year and try again. Would the second try be natural, effortless, spontaneous, emotional etc…

Maybe like this (not blues related). You put on a single minor chord. You can play all 12 notes for hours and see which you like “by ear” and make phrases and memorize which you like and have their sound in your mind. Or you might “know” that dorian, phrygian, aeolian work over minor chords. So you try out each 7 note subset for phrases. Maybe you find one of them to suit your mood. Then you can try add a chord to make the progression but retain the mood. Again you can fish around for hours or days which chord to add. Or from knowing which modal sound you like you would know from theory a chord that fits with the first one. Than you jam your mode over these 2 chords with a distinct sound and you fish for phrases you like and add them to your arsenal to play over that mode, just like one learns licks that fit blues progression. You repeat for hours a day for years. Works by ear search, works by knowing some theory. But relying on theory gets you jamming modaly much quicker. And you build your vocabulary for a given mode/mood/progression. Each time you improvise over it you draw phrases out of your vocabulary, mix and match, just like you would to improv over blues once you have an arsrnal of licks/phrases you tried/tested/practiced for a lot of time.

I dont have a great ear, i have no time to find out stuff for hours each day just by ear, but i learned some theory along the way. So i made up a small 2 chord groove and improvised on the spot using dorian only from my “theory” knowledge. Hopefully it conveys the dorian mood. It is an example of how theory helped me play something (whether good or awful) truly improvised on the spot. If i had time to explore for a couple years 5-6 hours a day i bet i would become a decent dorian mood player. I work with what i have in my 60 mins a day.

When i learned basic triad “theory” i put on a single chord track and played just those 2 neighboring triad notes mostly not even thinking about the scale which “fits”. Again good or awful this is my “theoretical” jam over a single chord.

@sly Thanks well played and rather thought provoking. I have not embraced modes, (although I slipped in Mixo earlier I only worked that one out this week) I probably do play modes though. The jazz improv that I did on my jazz learning log was straight off the top of my head and dragged from my memory bank somewhere. No idea what I played but a lot of blues based pentatonic probably. Defo not jazz. I did manage to throw in one Cmaj7 arpeggio via conscious effort.

Your style of music is not something I’m au fait with at the moment. I’m firmly steeped in blues progressions and particularly late 60’s early 70’s British blues players. Branching into more jazzy blues has made me look at what I already know from a theory perspective and particularly how to play the changes. I guess I better re-enrol and finish PMT!

1 Like

Thanks for sharing this Roger, very interesting video and much to explore.

@sclay Shane an interesting topic and one of those eureka moments I guess. I too have never thought of the non diatonic aspect of the standard Blues I7 IV7 V7, just accepting the Blues for what it is. Food for thought for sure.


1 Like

nice stuff in your log there. one of my long term goals is to mess a bit with jazzing up the blues or rocking up the blues or… picked blues as kind of a starting point for so much and enrolled in blues immersion. learned a couple of min7, maj7, 7, dim grips. and sometimes do a couple ii-V-I cycles just to enjoy those beautiful sounds. but, since i have 60-75 mins a day have to pick my battles and stick with them. Theory or no theory you are doing fine. I just wanted to show what i meant by “theory can/might help” getting somewhere a bit quicker or at least offer some avenues to explore quickly if one cant afford listening and trying out by ear all day long (wish i could). :v:

Yes, blues in A is really in A. The Western European concept of keys does not apply to the blues. An A7 chord in the blues is not the V7 chord in the key of D, it’s just… an A7 chord. It is most likely to be the I chord in A or the IV chord in E. The V7 chord is a completely optional feature of blues. There have been attempts to explain the blues retroactively using Western tonal theory or jazz-style chord-scale theory, but your ears should be enough to tell you that these are the wrong tools for the job.

There is not a fully fleshed out theory of blues harmony, though there are some proposals. The most plausible one I have seen is that blues derives from West African tuning systems based on the natural overtones of strings tuned a fourth apart. In A, that would be the overtones of strings tuned to A and D. The harmonic series of A gives you A, E, (mildly flat) C-sharp, and (very flat) G. The harmonic series of D gives you D, A, (mildly flat) F-sharp, and (very flat) C.

Whatever the origin of blues harmony might have been, the main thing to take away here is that Western European concepts of tonality and key do not apply. Not only are you routinely playing minor thirds on top of major chords, but you are very often bending those minor thirds sharp so they are really neither minor nor major.

Someone else in the thread linked to a blues tonality treatise that I wrote, but I recommend reading this more accessible version instead: Blues harmony primer – The Ethan Hein Blog


@ethanhein Love reading them all. Very nice texts.

1 Like


I always feel a sting every time somebody says “bend it a bit out of tune” when talking about the blues bend/curl. Even great musicians and music teachers say that. I guess it’s understandable because they speak of it in relation with the chromatic scale and try to apply western music theory on it. Which is what most people who are trying to learn the blues can relate to. But one should remember that the blues did not originate from western/classical music.

The world is full of music that is not bound to the chromatic scale and that is traditionally played with instruments with endless notes, like fretless string instruments (like the Oud, the great-great-grandfather of the guitar, or even vocals). It is quite possible that this also applies to the African music that influenced the blues (if some has source to confirm that, that’d be great). It’s about how it feels when listening to it. But of course, being exposed to that type of music reprograms you brain to get used to these notes and accept them, in the right context.

Firstly hi Ethan @ethanhein and welcome. Writing as a Western European, I have grown up with the blues and it is totally familiar to me so to my ear it sounds fine. The dissonance of the 7’s is probably what gives it the edge.

[quote=“sly, post:38, topic:333556”]
I just wanted to show what i meant by “theory can/might help” [/quote]

If left to my own devices, in a blues improvisation, I will invariably target the 7. That gets to be rather predictable and as bad as always landing on the tonic/root. It is good to open yourself up to other concepts to break out of these ruts. For me these discussions and Justin’s jazzing up the blues lessons have helped me open my ears and re-evaluate what I have done before. This is neither a marathon nor a sprint as there is no finish line.