• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Basic Theory Questions

JaminDyer

JaminDyer

Guest
Jul 25, 2013
88
49
Liverpool
#1
Hello TB!

I was pushed into playing piano when I was about 6/7 (don't get me wrong, I'm glad I was) and have kept it going. I have learned a fair amount of theory from this, but I feel that although I know a decent amount, I don't feel I truly understand it all.

My main question is about pentatonic scales. I know how to play them, but why are they like they are? Why does the minor pentatonic include a note not in the harmonic minor scale?

Another question I have is about modal scales. How do they work? Say you played a Lydian on A, what does that mean?

I've been trying to work out basslines out by ear recently, and some I can easily tell what key and scale they use, but others I just haven't got a clue!

I may remember some of my other random theory questions later, but here's two to begin with!

Thanks for any help

Ben
 
#2
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.
 
#4
Thanks for the answers!

Why are the two common pentatonic scales used so often then, and taught as a standard?

and regarding the modal scales, and working out songs by ear, does it make a difference? If a song was written in A Dorian, would it not sound the same as if it were written in G Major? or does it keep I ii iii IV V vi vii* with the modal scale? I'm not sure how to explain my question :S
 
#5
Don't get too hung up on basslines conforming perfectly to a scale. A lot of bassists use things called chromatic leading tones to get around a progression... Leading tones are notes that are not necessarily a part of the arpeggio or scale that you are using for the chord you are playing under, but they provide a strong lead-in to the next chord. Ex. going from A7 to Bm7, one could use an A# to get to the next chord. In practical theory terms, you are flatting the 2nd in your A mixolydian scale to do this.

As far as your question about A dorian, if you see a chart written with a single sharp on the key signature, then there you go, its in G major. Your I chord is G+, ii is A-, and so on. But for some songs in G you can feel free to use that A dorian scale on your ii chord if it works with the song. no matter what mode you base the song around, the song is still rooted in the major scale the mode coincides with. If its in E minor, its still in G major. If its in A Dorian, its still in G major. The notes don't change. Even if the song is based around the A dorian mode then you can think of it being based around the ii... I really edited that reply down so if it does not sound coherent let me know what didn't make sense and I will try to explain it better.
 
#7
JaminDyer said:
Thanks for the answers!

Why are the two common pentatonic scales used so often then, and taught as a standard?

and regarding the modal scales, and working out songs by ear, does it make a difference? If a song was written in A Dorian, would it not sound the same as if it were written in G Major? or does it keep I ii iii IV V vi vii* with the modal scale? I'm not sure how to explain my question :S
Click to expand...


Very good question.

IMO why modes sound different than the major scale they are derived from is because of the lowest bass note. Over a C major chord if you have the lowest note start on D instead of C you imply a different voice (dorian in this case), which does sound different.

As a keyboard player you should understand this as the same concept as slash chords where the bass or lowest note is not the root, i.e. C/E. So while these are the same notes as a standard C triad by placing the 3rd as the lowest note you create a different sound with the same notes. This is the same concept as modal scales, the lowest note drives the tonality.
 
#8
Ok thanks, I feel like I'm understanding it a lot better now.. so a mode wont change the tonality of a piece, but it will slightly change the texture of it?

Thanks Deste, I'll look it up!

I'm not sure if I have any more questions at the moment, but I'm sure I'll think of more soon :D
 
#9
"Why are the two common pentatonic scales used so often then, and taught as a standard?"

I have always thought of the Major and Minor Pentatonic scales as DISTILLED versions of the Major Scale and the Natural, or sometimes referred to as the relative minor scales. They are each just a simpler version of the original, which contain only the notes which clearly outline the MAJOR or MINOR sound. The reason Major and Natural Minor scales have such importance in music is because they are the only scales in music that we base an entire KEY off of and have actual key signatures for.
 
#10
One thing that might help clarify how the modes of any key work, is to remember that the original scale, say C Major, has 5 whole steps and 2 half steps. (With the half steps between the 3rd and 4th and the 7th and 8th note of the key.) Therefore ALL the modes of the major scale have 5 whole steps and 2 half steps. The difference is in WHERE the half steps fall in the scale, which shifts every time you choose a new starting note. This is why all 7 modes of the Major scale sound different. To me, the tonality of each of them is unique, even though they are essentially the same 7 notes every time, just in a new sequence. :hyper:
 
#11
Forgot about that question!

That's making more sense now, thanks. So when a guitar is using a minor pentatonic scale, it would sound fine to use a natural minor scale on bass, right?

I hadn't really thought about it much before, but is a relative minor, a natural minor because it's the Aeolian of the major?
 
#12
I used to tell my students...if u know the major(ionian) scale...u know ur modes...not so simple BUT all modes ade just the major scale starting and ending on any note NOT TONIC(which since octave is same note as tonic)..this gives u 6 note/key choices. Unfortunately. ..the finger patterns r all different in all degrees but once learned this gives u the ability to solo or riff make in many different keys from tonic. You r always playing the same 7 notes in all keys with the same intervals(think half step..whole step)...just starting and ending on in scale n I n tonic notes. For instance the intro to "sweet emotion" is in A mixolydian(all the same notes and intervals as D major). So if u played the Dmajor scale on bass up 2 octaves(pretty far up on the neck I may add)...u would pick up all the notes with the same interval spacing as A mixolydian when u hit the cirst A on up to octave A(actually u would keep going till u hit 2nd octave D since u r playing 2 octave D major scale).
 
#14
Couple of things --
IMO the pentatonic is, as mentioned a shorter version of the scale. The notes in the major pentatonic scale are R-2-3-5-6 which leaves out the 4 & 7 notes of the parent scale.

The notes in the minor pentatonic R-b3-4-5-b7 will leave out the 2 and 6 of the parent scale. .

Notice each will have a root, 3 (or b3) and the 5. The basic building blocks of a chord and then each will have two safe passing notes. That combination of notes can make a pretty good melody - from only 5 notes. And if you are using the songs chord tones for a bass line - well the R-3-5 really fit in nicely.

Easier to improvise a tune using 5 notes instead of 7. And then the chords pentatonic over the chord does make an acceptable melody or bass line.

OK that out of the way. Your question on modes - remember there are two ways to talk about modes.

1) Relative modes where the key changes and the notes stay the same and then...

2) Parallel modes where the key stays the same and the notes change.

Both methods get to the same spot, just use two different roads getting there.

Most of the time Internet questions, on modes, are answered with both methods, a few bits of relative and then some one else will add a few bits of parallel. Normally the writer does not let you know which method he speaks from. So it gets confusing....

I found this video to be helpful. [Invalid or Expired Link Removed] Scott will first talk about relative modes and then he will bring in parallel modes. Use either way you understand modes best. Once I understood parallel I never went back to relative.
 
#16
Some incorrect info posted above.

Hard core theorists subscribe to the following:
C major pentatonic: C D E G A
C minor pentatonic: C D Eb G A

The so-called minor pentatonic espoused by some others is simply a reordering of a major pentatonic. If the C major pentatonic is played with a beginning note of A, is it an A minor pentatonic? No...it is still a C major pentatonic (staring on its 5th note).
Check this out in any reputable theory book (Piston, etc.).
 
#17
lsabina said:
Some incorrect info posted above.

Hard core theorists subscribe to the following:
C major pentatonic: C D E G A
C minor pentatonic: C D Eb G A

The so-called minor pentatonic espoused by some others is simply a reordering of a major pentatonic. If the C major pentatonic is played with a beginning note of A, is it an A minor pentatonic? No...it is still a C major pentatonic (staring on its 5th note).
Check this out in any reputable theory book (Piston, etc.).
Click to expand...

Not so sure about that.

I learned it this way:

Based on the same idea as a Major-to-Minor relationship.

C Major to Relative A Minor.
C Major Pentatonic: C, D, E, G, A
A Minor Pentatonic: A, C, D, E, G

C Major to Parallel C Minor
C Major Pentatonic: C, D, E, G, A
C Minor Pentatonic: C, Eb, F, G, Bb
 
#18
lsabina said:
Some incorrect info posted above.

Hard core theorists subscribe to the following:
C major pentatonic: C D E G A
C minor pentatonic: C D Eb G A
Click to expand...

A possibly ignorant question, but is that version of the minor pentatonic derived from the melodic minor scale? And if so, would you also be expected to play it differently on the way down (i.e., basing it on the Aeolian, therefore playing Ab)?
 
#19
lsabina said:
Some incorrect info posted above.

Hard core theorists subscribe to the following:
C major pentatonic: C D E G A
C minor pentatonic: C D Eb G A

The so-called minor pentatonic espoused by some others is simply a reordering of a major pentatonic. If the C major pentatonic is played with a beginning note of A, is it an A minor pentatonic? No...it is still a C major pentatonic (staring on its 5th note).
Check this out in any reputable theory book (Piston, etc.).
Click to expand...

That "hard core theory" minor pentatonic sounds like a minor arpeggio with an added 2nd to me.

In every musical context i've seen it (blues, folk, rock, metal, funk, hip-hop and jazz) when somebody says "C minor pentatonic" they mean 1st, b3rd, 4th, 5th and b7th or C, Eb, F, G, and Bb

If you want to get into proper physics all scales are derived from the harmonic series http://en.wikipedia.org/wiki/Harmonic_series_(music)

Pretty much every culture has picked out the notes of the pentatonic scales for their own music, but they seem to pick different overtones to make up the rest of their scale.

In western music all the terminology is based around the Major scale (this makes sense because this is the one they use the most, hence "major"). Classical musicians didn't originally "derive" the modes from the major scale (that was the Greeks), they played them all. But as it developed classical western music became all about harmony and the V to I chord progression became all important. For the V to I to happen a scale needs a sharp 7th, so the Ionian mode fit the bill and got labled the "major" scale. None of the other modes fit those chords, so they dumped them all, with the exception of the Aeolian (Natural Minor) which they amended to fit the V I by raising the 7th to create the Harmonic Minor. This created a big interval between the 6th and 7th which didn't sound very melodic when ascending the scale, so they raised the 6th when ascending to create the Melodic Minor

Modes got kept in some church music and in folk music where they weren't into the V I harmony as much. In folk you don't play a song in G mixolydian as a song which is in C major, but you're shifting your focus to G. You play it as a song based around the G7 chord.

I love the modes. I can drone on the dorian or mixolydian all day long.
 
#20
gavinspoon said:
In every musical context i've seen it (blues, folk, rock, metal, funk, hip-hop and jazz) when somebody says "C minor pentatonic" they mean 1st, b3rd, 4th, 5th and b7th or C, Eb, F, G, and Bb
Click to expand...

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.
 

Latest posts

Top Bottom
Back