Music Theory for Banjoheads, pt. 1

I like to give my jazz students a theory handout, in workbook form, just so we're on the same page, using the same nomenclature, etc. I call it "What-you-need-to-know-to-play-in-my-band!" I've also noticed that many articles on various aspects of banjo playing necessarily assume no theory knowledge on the part of the readers, so a lot of column inches are used in quickie explanations of I-IV-V's, scales, what-have-you... So I thought maybe my little blog here could be a one-stop theory shop for banjo players. 

We'll be doing scale construction, intervals, triads, and 7th chords, with examples you can try out on your banjo. OK, first...

Major Scale Construction

Let’s just get this out of the way right at the git-go just to make sure there’s no confusion. Here is what’s known as “the chromatic scale.” It is, in a sense, our musical alphabet:

C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C 

The distance from one note to its neighbor - or from one fret to the next - is called a half step. If you skip a note (move two frets) you have gone a whole step. Start with C on the 2nd string, and go fret by fret all the way to the 13th fret; that’s a one-octave chromatic scale from C to C.

The sign in front of the D-note, E, G, A, and B in the staff above is a natural sign, which cancels a sharp or flat and turns it back to, y'know, regular old D, E, etc. You don't use it unless you are cancelling a sharp or flat, or drawing a distinction in conversation, such as, "Should I play F sharp here?" "No. F natural." 

You have your natural notes (in boldface below) which are the same as the white keys on the piano,

C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C

and the accidentals, the sharps and flats, found on the black keys. 

C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C

A sharp sign (#) raises a note one half step, a flat sign (b) lowers it a half step. 

Major scale math

All major scales have four things in common:

1. Every one has seven notes: do re mi fa sol la ti and that will bring us back to do (oh-oh-oh)
2. Every letter name, ABCDEF and G is represented once only.
3. The spaces between the notes of a major scale are: whole step, whole step, half step, whole step, whole step, whole step, half step. (or: WWHWWWH) 
4. The key of C major is made up entirely of natural notes, all the others have sharps or flats, never both.

Let’s look at that Key of C. You’ve already seen it:

C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C

Here it is going up the b-string:

Let’s look at some examples, starting with the key of D-major (or just “the key of D”). First, here are two octaves of the chromatic scale to use for reference. 

C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C (C#/Db) D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C…(etc.)

Now if you count WWHWWWH along the chromatic scale starting on D, you should land on these notes (the ones in boldface type):

D (D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C (C#/Db) D 

Now the question is, F#? or Gb? Well, the key of D has to follow the alphabet from D to D, DEFGABCD, right? After E comes F, so this one has to be F#. Also, if you used Gb, then you would have two G’s in the scale, another no-no! So here’s your D-major scale:

D E F# G A B C# D

D-major is one of the “sharp keys,” so called because all the accidentals are sharps. It also is the only one with two sharps, so people will sometimes refer to a tune in D as being “in two sharps.” Musicians wanting to subtly communicate the key of a song to another player will hold up two fingers for the key of D. 

Let’s try a flat key, Eb-major. First do your whole- and half-steps (you already know it’s Eb and not D#):

(D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C (C#/Db) D (D#/Eb)

You know two things here: It has to be all seven letters in alphabetical order, and only flats, no sharps. So:

(D#/Eb) E F (F#/Gb) G (G#/Ab) A (A#/Bb) B C (C#/Db) D (D#/Eb)

Eb F G Ab Bb C D Eb

Eb-major, aka “three flats.” The signal for three flats is three fingers held pointing down. I was on a jazz gig once playing bass behind a singer who called a tune and wanted it in the key of E. No problem on my end. I’m an old guitar picker so I’ve spent some serious quality time in E. But it’s the also “the key of four sharps,” pretty gnarly for everyone else, particularly jazz pianists who don’t really like sharp keys in the first place. So the pianist turns to us and says “OK, key of Eeeee fellas,” holding three fingers down for Eb, “four sharps, key. of. E.” making sure we see his signal and singer doesn’t. We played the tune in Eb, a half step down from E, and the singer was none the wiser.

There are 15 major scales:

C, G, D, A, E, B, F#, and C#,

F, Bb, Eb, Ab, Db, Gb, and Cb.

1. Figure them out in the order I wrote them and see if you can guess why I ordered them this way. 

2. You’ll run into a little quandry with the keys of F#, C#, Gb and Cb, see if you can work through it.

3. See if you can figure out why there’s a key of Eb major but no key of D# major.

I’ll have answers at the beginning of the next theory post when we start on intervals. Good luck, see ya.