Harmonic sense of an Eb7 in a blues in E

Question

In this image a blues ends with the tonic chord (E7) preceded by Eb7. Beyond the chromatic effect that can be perceived, is there any way to harmonically define such an Eb7? In other words, what is the harmonic label to stick on this chord?

Answer 1

Don't try to force a harmonic function onto it. It's just a decoration created by planing up from the same shaped chord a semitone lower.

It's possible a 'blue' G♮ is intended in the last chord, and that E7 is written as a simplification of E7(#9). But I suspect that either the chord symbol or the staff notation is a misprint. And it COULD be the notation. Yes, the tab agrees with the notation, but one could have been automatically derived from the other. So correct the chord symbol or correct the notation. Your choice.

Answer 2

It's simply a chromatic move, playing one semitone down from tonic, then arriving at the tonic. Written as D♯7, although called E♭7, all three notes would play on that chord, then one fret higher.

To me, at least, the G♮ written in the staff ought to become G♯ on the E7 chord. If it is indeed the end, where's the double barline?

I feel that there's a mistake between tab and dots. Usually a piece in key E (Blues, E7?) will end on a dominant rather than a m7 chord. Or maybe a mix - known as E7♯9.

So, answer - a chromatic move.

Answer 3

There's a thing that I think provides a context.

It's in E, so we have E7 - E G# B D. Pay attention to the third and seventh, G# and D.

Now, consider A7. A C# E G. The third and seventh are C# and G.

Let's move to B7. B D# F# A. D# and A.

In a jazzier style, you can drop the root (because the bassist plays it) and the fifth (because it's obvious) and play the harmony three note pairs that are right next to each other.

Now, Eb7. We're talking sharps so far, so D#7. G and C#. That's the same notes as the A7, except the roles of the notes are reversed ( 3 <-> 7 ). A major third and dominant seventh are a tritone away from each other, and using the Eb7 instead of the A7 is an example of Tritone Substitution.