Ok so I recently learned how to harmonize the major/minor scales in sevenths, prior to that I didn't think much about sevenths in music.

Now according to the harmonized sevenths if I play in E and I use a I-IV-V I should be playing:


However, it sounds more bluesy to my ears to just play them all as dominant sevenths.

Does the blues deviate slightly from the typical theory? I'm probably going to sound like a massive noob here but I definitely want to know whether this is correct or not.


Edit: can someone also tell me how to add people so I can chat
Last edited by -TM- at Aug 5, 2010,
Blues IS mostly played with all dominant seventh chords, yes. I have no idea of the theory behind blues and the dominant sevenths, I just know that they work

You can always experiment with new chords, though
I wouldn't say it "deviates" If you are playing in A blues, you will possibly start the progression from the 5th chord of the c major scale. the 5 chord of a major scale is a dominant chord, so A dominant 7. after that try playing D dominant 7 or 9 and an E dominant 7 or 9, I'll be honest I'm not sure why those last 2 sound good as dominants, I guess it's because dominant is close to minor but these ones fit with that extra note in the blues scale.
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you can use major 7ths in blues...there are many variations to the I IV V progression...in jazz the chords are substituted, altered, and back cycled making the placement of the familiar chords hard to recognize...but they are there...

for me the blues is a 12 bar structure...what goes in that structure is up to you...if you can make it work and it sounds good..

play well

It is more bluesy to play them as dominate 7th. E major pentatonic scale is 1, 2, 3, 5, 6 and the notes are E, F#, G#, B, C#. E minor pentatonic scale is 1, b3, 4, 5, b7 and the notes are E, G, A, B, D.

You will realized that E major pentatonic does not have the leading tone or the 7th and E minor pentatonic has the 7th but it is a flat 7th.
The notes in E major 7 chord are E/G#/B/D#, therefore the D# has the tendency to imply a major scale rather than a pentatonic scale.
The essence of blues is taking a major key and flatting certain notes (such as the 3 and the 7, both of which manifest themselves in the minor pentatonic).

This is why it is common to see a bIII or a bVII in rock/blues.

Knowing this, looking at a I7 IV7 V7 progression seems very simple. Let's take the key of C. The basic triads are C (C E G), F (F A C), and G (G B D). Adding the b7 to each of these introduces a Bb (the b7 of the I, in other words the b7 of the key in general), and an Eb (the b7 of the IV, in other words the b3 in relation to the tonic). And the b7 of the dominant is diatonic.
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The dominant seventh chord often used in bluesy music as a (not so good) stand in for the 4:5:6:7 chord. That 7:4 seventh is regarded to be bluesier in character than the minor seventh, which is just the next closest thing.
Creating an ambiguity between major and minor is a big idea in blues.

Look at the formula for a dominant seventh: 1-3-5-b7

The b7 implies minor seventh, but the major third implies major seventh, thus clash and blues!1

Try using the Mixolydian mode to solo over a blues progression with dominant sevenths.