Basic Theory Questions

[taphappy]

Sidenote: Blipping back to modes for a second. Most of this has been covered, but I'm gonna reformat and try at the basics from my limited theory/piano perspective:

Piano is an instrument that makes modes second nature. But transposing sucks. For strings, it's mostly a simple shift up or down, unless you run out of space.

The diatonic scale (5 whole steps, 2 half steps) is what we're talking about, at the moment. For ease of use, we'll start it at C Major, and stick to the white keys on the keyboard.

So, the Major scale (C-C) is a mode (Ionian), as well as the natural minor scale (A-A, aeolian). The other five diatonic scales/modes retained old Gregorian names, because the Church didn't dig them. And, honestly, after Major and minor...where do you go? Mixolydian = Majorish? Phrygian = minorer? Locrian = minorest?

Now, to add a little extra useful info to the mix (hopefully) if you break the notes of these scales down into 7th chords, they're mostly M7 or m7, with one dominant (7), and one half-diminished (m7b5). We tend to arpeggiate all of these on bass, cause they're economical and sound spiffy. Brb on that.

Using just the notes in C Major as the parent scale, these are the relative modes, their relative 7 chords/arpeggios and their scale degrees. So if you play the scale of:

C-C = Ionian/Major (M7) I
D-D = Dorian (m7) ii
E-E = Phrygian (m7) iii
F-F = Lydian (M7) IV
G-G = Mixolydian (7) V
A-A = Aeolian/Minor (m7) vi
B-B = Locrian (m7b5) viiø

Chords: CM7 Dm7 Em7 FM7 G7 Am7 Bm7b5

Because the relationship of whole steps and half steps changes with where you start the new root note (CDE is not the same as DEF), it makes different scales. They all have a totally different sound, like Major to minor.

On your keys, play a Dm7 chord with your left hand, and run the scale of D-D on the white keys. That's D Dorian. F7 left hand, with F-F on the white keys, F Lydian. Bm7b5 left, with B-B white keys, B Locrian. And so on. Play a C Major scale while holding down those chords individually, listening to how the chord changes the feel of the entire scale. Play a CMaj7 chord, and walk through those modes. Try it with the other chords and modes. Go random. Shoot some heroin, mash it all together, occasionally headbutting the keys, and that's jazz.

Ba dump chik.

If you go to C# Major, same deal, just bumps up a half step. Just C#M7 D#m7 E#m7 F#M7 G#7 A#m7 B#m7b5. And that's where it's easier on strings.

One obvious practicality of this is if somebody calls a jazz ii-V-I in C Major, you know it's going to be Dm7 G7 CM7. Those are the basic chords, and your root arpeggios. If you want root modes over the changes, D dorian, G Mixolydian, C Ionian/Major. Or you can think of it as just going bonkers in C. Or play any of those relative modes/chords/arpeggios that fit the parent scale, throw in some chromatics, and see what you like.

Once you figure out all these basic rules, then you should have a foundation. Then you'll find there are tons of amazing options that ignore the rules, but they have rules, but there are no rules, and your mind implodes, and that's where I'm at. I should be practicing right now, but I broke my soft chewy center, and my brain's off blowing pretty little bubbles somewhere.

I'm still a work in progress on all this, but hopefully that's (1) accurate, and (2) helps

 

[jamminology101]

Absolutely agree with this, as this has been my experience too. However, as you say, it's when I'm hanging with my fellow jazz and blues performers (or any other type of "popular" music players). But, I remember when discussing this material in grad school (yes...we actually sat around and talked about scales, modes, etc.!) the thinking was that minor pentatonic was the same as a major, but with a flatted 3rd. It would be nice if any members who are currently studying this material at an advanced level within a "traditional" theory or composition program could chime in with what the thinking is today. Maybe it has morphed...
All in all, a good discussion.

Look at "smoke on the water"....the majority of that song is based on the G minor pentatonic scale...even the backing groove that is in G and C during the guitar solo is grooving hard with the scale....good stuff.

 

[Lownote38]

Don't know if I can answer all of these to your satisfaction, but I'll give it a go!

Firstly, the pentatonics are a little misleading. Strictly, a pentatonic scale is any five notes of your choosing. (In theory, you can invent your own; I believe some composers such as Scriabin did.) So when people refer to "the major pentatonic" and "the minor pentatonic," they're actually referring to two particular pentatonic scales which have become very widely used. So whilst a lot of guitarists, bassists and jazz musicians know what you're referring to by "the major/minor pentatonic," it's probably not a term that a purely classically trained musician would recognise.

The "minor pentatonic" is not derived from the harmonic minor scale - it's actually derived from the natural minor scale (also known as the Aeolian Mode). This contains all the same notes as a harmonic minor except the seventh is flattened - and that, presumably, is the note which is causing you consternation!

Speaking of modes: they work in the same way as scales, insofar as any mode you choose will have the same intervals between the notes regardless of the key you choose. So just as C major and D major have the same intervals between the notes, C Locrian and D Locrian will also.

Modes are derived from the main scales (major, harmonic minor, melodic minor). I'm hazy on the story, but I find the best way to understand it is to envision an instrument which is built to play one particular scale. Say this instrument had all the notes for C major, but you don't want to play a piece in a major key. If you started your scale from the D instead, you'd have something which sounded a bit different - this time, all the notes are the same, but because you've changed the starting position, the intervals are different. That set of intervals came to be called the Dorian mode. Not every mode has a name, incidentally - all modes of the major scale do, but they weren't quite so meticulous with modes of the minor scales.

Actually, the minor pentatonic was derived more from the Dorian mode. That's why you hear a major 6th so often when people play the blues. A minor 6th wouldn't sound quite right where you would use a minor pentatonic scale. You might also say it is derived from another blues type chord Dom7#9. That's a common chord type used in blues, and the #9 is really a minor 3rd, so a minor pentatonic scale can be used there as well.

 

[AuntieBeeb]

Actually, the minor pentatonic was derived more from the Dorian mode. That's why you hear a major 6th so often when people play the blues. A minor 6th wouldn't sound quite right where you would use a minor pentatonic scale. You might also say it is derived from another blues type chord Dom7#9. That's a common chord type used in blues, and the #9 is really a minor 3rd, so a minor pentatonic scale can be used there as well.

I can see that working...but then are we talking about the minor pentatonic which most people here seem familiar with (1, b3, 4, 5, 7) or the one that lsabina mentioned (1, 2, b3, 5, 6)?

In the first case I can see it working for either the Dorian or Aeolian as that particular pentatonic omits the 6th, but of course the second case would either have to come from the Dorian or the melodic minor - so I guess that clears up the question I asked lsabina earlier!

 

[lsabina]

Look at "smoke on the water"....the majority of that song is based on the G minor pentatonic scale...even the backing groove that is in G and C during the guitar solo is grooving hard with the scale....good stuff.

Or, is it based on a G Blues scale? Ah...another point to ponder: is (what most people call) a minor pentatonic simply a blues scales with an omitted note? (Maybe we can go with Aqualung here!)