Flattened 3rd and Flattened 7th. Why use one over the other?

[Mad Martigan1]

I’m studying pentatonics and the blue notes. I understand what these notes are and where they are in position playing but I’m not sure if there’s a rule to using them. Why would someone only use the flattened 7th, is this just personal taste? If I use both in a solo is that to much? 🎸

[rcc56]

Blues is about sound, emotion, and mood. There are happy blues, sad blues, bawdy blues, etc., and they are all approached differently.
Sometimes we don't use the seventh at all, we use the sixth instead. And sometimes we use both. We rarely use the major seventh.

There is no why, there is only what works and what doesn't work at any given moment.

While theory can be useful to present some concepts that might work, it does not tell us what will or will not work in a given context. Look at the theory, play around with it, but then use your ear to guide you. And I don't know of any kind of music that resists specific theoretical boxes more than blues does. It absolutely rebels anytime you try to put it in a box.

Or, it might be said that it's easier to put a wild cat into a sack than it is to put blues in a box.
And there is no "blues scale." There are only scales that are used in the blues. These include, but are not limited to: the "major pentatonic," "minor pentatonic," and the mixolydian mode.

Flatted thirds are the biggest area of confusion. There are barely flatted thirds, significantly flatted thirds, and major thirds that are not flatted at all, but are simply slid into.
The great Josh White was known to use a third in his "sad" or "wistful" blues that was flatted so far that it wasn't a third at all-- it was a raised second. And it worked.

[Mark Gunter]

Yeah, you can find “blues scales” in books and taught by musicians, but you won’t find agreement on exactly what a blues scale is. In the actual playing of the blues, you can use any color that works including the tritone, and sometimes chromatic runs of four notes, sometimes the sixth adds more color than the third or seventh, what a great answer Bob gave above. There’s nothing wrong with studying the theory, scales, etc. in fact, I engage in theoretical dissection of my playing a lot, but the blues is all about feel … the heartbeat, and the musical speech … so best to learn some vocabulary, learn some licks and passages and get the feel down. Then you can find how to choose notes and turn phrases on your own terms, rather than seeking an external rule or answer to your question. The question won’t really matter much at that point.

[des]

Here's a few suggestions to the specific original question. These are perhaps more relevant to the jazzier directions in the blues - but no harm in that.

So, talking about 12 bar blues here, the minor third is probably going to sit well over the IV chord ( certainly the 4 chord will be on bars 5 & 6 and frequently on bar 2) and maybe over the V chord on bar 9. The major third may go well over bars with the I chord. You might be surprised at how cool and bluesy that can sound.

Extending this to the pentatonics - similarly use the minor pentatonic scale over the IV and major pentatonic over the I . The V chord can go either way.

Regarding the flat 7 - that tends to go everywhere throughout - but very occasionally you can hear a major 7 over the final cadence and it can sound absolutely deadly.

It is possible to explain why all this should be so - but - just try it and see if it feels right.

None of this by the way is getting into the substituted chords that come up in the jazzier blues tunes - these moves work over both the standard and the jazzier blues 12 bar blues tunes.

So for two examples "Tenor Madness" by Sonny Rollins really spells out the switching between major and minor thirds. "Sandu" by Clifford Brown does all the above.

Here's my quick and dirty one take recording of the head of Sandu. I also attach the sheet music - which shows exactly where major and minor thirds and flattened and (just one) major seventh occur. By the way it's in Eb and sits perfectly on Mando for all that.

These theoretical ideas were suggested to me by my brilliant sax teacher and were a real light buib moment for my playing tenor sax and mandolin. Next step is to improve my "feel" by trying get on top of another highly theoretical notion that distinguishes the good musicians from the rest of us - namely learning to play on, behind and ahead of the beat.

Happy Paddy's Day!

[Jacob]

The blue notes are the result of the pitches used by slide guitar and mandolin players and may require significant "bending" on fretted instruments played with no slide.

[Nevin]

My thought on the minor 7th is that in classical tonal music chords usually resolve in a logical manor to a final ending. A major 7th can really push that along. Blues has more of a series of repeated riffs and changes that keep them interesting without moving in a particular direction. The minor 7th fits that better than the major 7th in most cases.

[Jim Broyles]

The two scale notes you are asking about have different uses and purposes. The flat 3rd is what produces the mournful quality of the blues. It is especially effective when you bend it toward, but not all the way to the major 3rd. Of course, on the mandolin, the major 3rd is hammered onto from the minor 3rd a lot. The serves a similar purpose as the bend. You are producing that ambiguous sound of major/minor over the same (major) chord. The flat 7 resolves to the IV from the I, and to the I from the V. As far as soloing, you'll likely find that both notes fit the bill equally well.

[JeffLearman]

Rule 1: There are no rules.

Music theory is about understanding and communicating about music, not a set of rules for what you should and shouldn't do.

Next, there's also a big difference between "playing a minor chord" and "playing in a minor key." (When the 3rd is flatted, it's called "minor," for key or chord.) The difference is pretty simple though, in the former case it's momentary, just for the chord; in the latter case it's the "tone" throughout the tone or passage. Have you heard the children's piano tune, "Heart and Soul"? It's in a major key, and the first chord is a major chord, but the second chord is a minor chord (but all notes in the same key as the original chord.)

Let's skip keys for now and stick with chords, for simplicity.

As I mentioned above, a flatted third makes a minor chord (as opposed to a major chord.) It sounds a LOT different form a major chord. Try it and see! Best on a piano if possible. Minor chords are everywhere, not just the Blues, so don't limit your thinking that the blues is about minor or vice versa. Here are some songs that start on a minor chord (and are in a minor key):
* Summertime
* Ain't no Sunshine
* California Dreaming

The following start on a major chord (and are in a major key):
* Hart and Soul
* Jingle Bells
* White Christmas

While we often say that minor gives a sad feeling, and it's true, note that White Christmas above has a very melancholy feeling to it, yet it's in a major key. So, don't get stuck on that idea; it's just a generalization.

Really, REALLY, get this idea down, and be able to mentally distinguish a major from a minor. Spend some time with it!

After you have that idea down, then it's time to start pondering 7ths. What they do is rather different in major vs minor, so you need to have that down first. Baby steps! But, here's a very general guide:

Major3+Major7 ("major 7th" chord): very harmonious mellifluous, "totally major" feeling
Major3+minor7 ("dominant" or "7th" chord): Major but with a bite. Very popular in Blues, much more so than minors!
minor3+Major7 -- skip this for now. It's a rather special purpose tool.
minor3_minor3 ("minor 7th" chord): This is just a minor chord with more sweet sadness.

First understand the chords, and later work on how the notes in the chords (and their respective scales) work in melodies. And by "understand" I mean "be able to recognize, play, and have an idea when they fit in."

[JeffLearman]

Once you're comfortable with the chromatic flatted 3rd and 7ths above, here's more context to help understand "blue notes."

The main "blue note" is a note that is somewhere between the flatted and natural 3rd. It's usually played over the mixolydian scale, meaning it's played over the "7th" chord (M3m7) or it's related chords. Oddly enough, one rarely plays a blue note 3rd over a minor. These notes started out in singing, and later instruments learned to imitate it.

Another great blue note is the flatted 5th. (The "standard" blues scale is 1,b3,4,b5,5,b7,8 by the way.) Well, another case where one can play almost any pitch between two notes is between the 4 and flatted 5.

On mandolin, notes are rarely bent (unless you're playing a 4-string mando, like Johnny Gimbal of the Texas Playboys.) So, while it's nice to know about "blue notes" one generally has to sit this out, or sort of allude to them by sliding. As a piano player, I empathize.

Oh right -- there is one other context for blue note where the Mando can join the fun. That's when we play a flatted third when soloing over a major chord (or key). Very very common (almost "de rigueur") and definitely the Blues (or blues-inspired.) In this case, that "major" chord will pretty much always be a "7th" chord or its associated key. I can't think of a case where I've heard a minor 3rd play over a major7 chord. No doubt there are cases, but it's not for beginners. I doubt I've ever done it.