It's easy to see which mode many chord progressions are in. For example, I-IV is Ionian; i-iv is Aeolian; i-IV is Dorian, etc. But I'm not sure how to analyze some progressions. For example, I-bVII-IV, I-bIII-IV, Ib7-IVb7, Ib7-IVb7-Vb7 (dom.7 blues). Are these simply "pop/blues conventions" that don't follow any specific mode?
Yes some can be Mixolydian, but usually the blue b3 is needed to create a stronger Tonality. This means you at least have an 8 note system. To me that's the main core Blues framework.Originally Posted by GitBox
Some are also Alternating Key songs like Sweet home Alabama, they can be heard as Mixolydian alternating with Major(Ionian). Several times in that song though the Blue b3 is added to the "Mixolydian", like the first note in the vocals, so it's really blues. Blue Notes are also used on the "Major" perspective in the guitar solo.
Just Mixolydian can sound "Celtic" or "Indian" and may need a drone to feel Tonal and stable. Blues however can be just as strong harmonically as Major. It's not a mode of Major, it instead adds additional blue notes to Major (or anything else you want really).
Major - 1 2 3 negative 4 5 6 7
Blues - 1 2 blue b3 3 negative 4 5 6 blue b7 7
There can be even more blue notes added, but that's enough for at least a 12 Bar Blues chord progression.
Last edited by Ken Valentino 2; 08-16-2017 at 05:05 AM.
blues scale consists of the minor pentatonic scale plus the ♭5th degree
-Wikipedia
Yes.
I-bVII-IV is mixolydian (provided I really does sound like I, otherwise the whole thing is really V-IV-I), but the others are rock conventions which, as you say, "don't follow any specific mode". They're examples of "mode mixture": the practice of using chords derived from different modes on the same root note; or of simply regarding some scale degrees as not fixed.
Blues sequences are based on the latter principle: not a mix of scales, but one scale where some of the pitches are variable. It seems that western theory has huge problems conceptualising that idea, while it's second nature to blues players, rock players, and many folk cultures. So "blues scale" is not exactly what Ken says, and not exactly what wiki says either (although Ken is closer).
Here's a rough guide as to how blues scale works in practice:
Each note is flexible as shown, with "gravitational" centres where the numbers are. The natural blue 3rd seems a little sharp of m3, but in practice moves around, and often resolves to the nearest chord tone (M3 of I or b7 of IV). The natural blue 7th is (some say) a 7:4 ratio somewhat flat of m7, but singers will often swoop up from that all the way to the tonic, or drop to M6, or sometimes move towards the M3 of V.Code:TEMPERED SCALE NOTES: 1 . 2 b3 3 4 b5 5 . 6 b7 7 1 BLUES SCALE: 1 <---3--> 4-><-b5-><-5 <--b7----->---->1
Of course, working with western instruments (tuned to the equal tempered scale) we have to choose chords to approximate what the scale typically does. It can certainly be simplified to a minor pentatonic, and if we build major chords on each step of that pentatonic, we get other useful notes too. So the I chord will give us a M3, the IV chord will give us M6, etc. That's what leads to the mistaken belief that blues scale can have many different (fixed) notes, or there are many kinds of blues scale. A more accurate view is that there's only one blues scale: it has five notes, of which all except the tonic are flexible, around certain centres and within certain limits.
The b5 is not really an additional note in its own right, but is an embellishment of 4 or 5. It always occurs either before or after 4 or 5, and resolves to one or the other. The other scale notes can jump around much more.
Of course, some kinds of blues (styles, periods or artists) do favour some positions of the blues scale pitches over others. In some styles you'll hear the low end of the 7th (nearer 6) more often than b7. Some styles will stick solidly to a 3rd close to m3, while others will let it go up to M3 now and then.
Last edited by Jon68; 08-11-2017 at 11:09 AM.
Yep those can be added as well. Like I saidI was just trying to tackle one concept at a time.There can be even more blue notes added, but that's enough for at least a 12 Bar Blues chord progression.
That puts us at:
1 2 blue b3 negative b3 3 negative 4 blue b5 5 6 blue b7 negative b7 7
And again there can even be more.
The slightly sharp b3 is 5:6, to me it's a Negative b3. It's darker than under b3 (or bent 2) which is 6:7. Both are used all over the place in blues.
The b5 can be several things, but the blue note version is really common.
Last edited by Ken Valentino 2; 08-16-2017 at 05:04 AM.
Hi,
Just to emphasis Jon68's point for the benefit of the OP, progressions like this are referred to as examples of Modal Mixture or Modal Interchange. They are a part of common practice harmony, which means they have been around for a long, long time, well before rock or jazz music (although these have their own clichés).
Do some Googling for more info, or check out Vincent Persichetti's 'Twentieth Century Harmony', or even the old Berklee harmony books which also explains it in detail.
It's a useful thing to explore in soloing as well as composition. You can look at routes that the harmony implied by your melodies can take that differ from what is written or what the band might be playing.
Cheers
Tom
Notice that this really ended up as two different questions. There's a clue in this.
1)What is I dom7, IV dom7 and V dom7?
2)Blues scale is a "minor" pentatonic with a b5
That alone (even if we're not at a subjective level) gives us 1 2 b3 3 4 b5 6 b7 7. That's only missing two notes! This would be extremely difficult for a beginner to handle. So unlike how most things are usually taught in this case the "scale" isn't the same notes as the chords.
The clue that I'm referring to is that the "minor" part is easier as a scale even though the same notes are in the harmony. If someone hears it as negative (which can easily happen with that scale)or if they hear it as a blue note it'll work either way. If they don't like the note they landed on (probably negative), you can just tell them to keep moving to a 5 or a 1. But if they happen to hear it as a Positive Blue note it could fit the harmony.
So I completely understand why it's usually taught this way. It works and can be objectively explained as a scale.
In fact I think part of the confusion was that the OP thought I was talking about a blues scale. So he looked it up in Wiki. Blue Notes can stand on their own. A Dom7 Key Chord is just that, a maj triad with a Blue Note (1:3:5:7). It can be heard on its own without any scale. Ironically the "Blues Scale" can be heard as negative instead. It was even defined as a "Minor" pentatonic! To me this can really confuse things at a subjective level.
I also wanted to clarify that the 4 talked about was negative. I've edited it, I apologize if it confused anyone. Additionally if it wasn't clear the Tonal Numbers listed were from the viewpoint of Key Centering on the 12 Bar Blues.
Last edited by Ken Valentino 2; 08-16-2017 at 06:04 AM.
useful information
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