Tonal Theory Applied to the Guitar, Part 1: Pitches, Scales and Keys

author: mhillips date: 04/25/2014 category: the basics
rating: 9.3 / votes: 34 
Tonal Theory Applied to the Guitar, Part 1: Pitches, Scales and Keys
Ok, so welcome to part 1 on my lesson on tonal theory applied to the guitar. In this lesson we will cover common scales, diatonic chords, cadences, chord progressions, and a few other similar and basic ideas that will note only make you a better guitarist, but a better musician.

I've been playing electric guitar for over a decade and have been serious into classical guitar and jazz for the last two years. I am currently studying music composition at a university and was more or less self taught. I did not have any professional training or lessons until two years ago when I started studying music with people who have been playing their instruments for over thirty years and have PhDs. I have probably learned more about the guitar and music in the last two years than the first eight years teaching guitar myself. Why am I telling you this? Because, a little theory or knowledge about music can make a HUGE different in how you play music and think about it. There are so many great guitarist who have little or no classical music training who are amazing musicians. There are virtuosic players that exist that cannot read standard music notation or have no idea what the technical names for the chords they are playing, and that is perfectly fine. But, if someone who could do anything on there instrument and understood how pitches relate to each other, they could take out all the guess out of making music and treat it more like a science. Are you struggling with improving over chords? Or knowing what chords sound good together or what notes work in harmonies and what notes sound too dissonant or undesired? Well than you stumbled across the right article! Hopefully beginners and advanced players can learn something new or maybe this can help clarify a few things. Anywho, enough with all the chit-chat... let's get started! 

Pitches in a nutshell

So I am assuming that everyone reading knows what pitches are. I am also assuming that everyone reading knows how to tune a guitar to standard tuning. EADGBE are the notes or pitches the guitar makes in standard tuning, when the fretting hand is not touching the fretboard. In western music, there are twelve distinct pitches that cycle up and down in octaves. Octaves are named so because in western music, diatonic musical scales and keys have seven different pitches and the first pitch repeats after the 7th pitch but in a different register. For example, the low open E string sounds two octaves lower than the high open E string.

The twelve different pitches are:
  • C (Rarely B#)
  • C# or Db
  • D
  • D# or Eb
  • E (Rarely Fb)
  • F (Rarely E#)
  • F# or Gb
  • G
  • G# or Ab
  • A
  • A# or Bb
  • B (Rarely Cb)
So these are the twelve basic pitches used in western tonal music. Now, for those of you who don't know, the reason why a D# could be called a Eb sometimes or why C could technically be a B# is because the names are enharmonic to each other. There is a "half-pitch" between every one of the seven letters (A-G) with the exceptions of E and B (which go straight to F and C respectively), which gives us twelve pitches. #s (pronounced sharps) indicate that a pitch is tuned up higher by one half step, or one fret or a semitone (all mean the same thing). Bs (pronounced flats) indicate that a pitch is tuned down lower by one half step, or one fret or a semitone. Sometimes you may see a box like icon in front of a pitch. That symbol is called a natural and means that a pitch is to be played without being sharp or flat. To relate this to the guitar, play your low open E or 6th string. Now put your finger on the first fret and play that string. That second note you just played was an F, which is one fret or one semitone or a half-step higher than E. Now put your finger on the second fret on the low E string. Pluck that string. What note was that? If you said F# or Gb than you are correct? Now go to the twelve fret and play that note on the low string. That was also an E, pitched one octave higher than the string when it is played open. Make sense? Now that we've brushed up on what pitches we have available and how to pronounce them and how it works on a guitar, lets move on.

Diatonic

What does this word mean? It means all the notes or pitches pertaining to a particular scale or key signature. In western tonal music, a diatonic key or scale has seven different pitches it and each pitch is represented with a different letter from the alphabet (A-G). Letter names cannot be repeated in a diatonic key. For example, in the key of C major (the most basic of all keys to talk about in regards to music theory), the notes are: C D E F G A B and then back to C. Notice that I didn't say something like C D Fb F G A B or C D E E# G A B or something similar. Yes, E# and F and Fb and E are different enharmonic spellings of each other (I mentioned that earlier), but you don't use these names because not every letter we have available would be used in our key. All letters must be used. Another example, in the key of G major, we would have G A B C D E F#, not G A B C D E Gb because then the letter F would not be accounted for. Why is the G major scale G A B C D E F# and not just G A B C D E F? We will get to that in a second. 

So now that we know that there are twelve pitches, and that we can use seven of them and every letter must be accounted for, lets talk about keys. Keys can be either Major or minor and are determined by the main/root/tonic note that is played and the number of accidentals used. Accidentals is another word for sharps or flats. Keys can be constructed using one of two formulas. The same two formulas can be used to make the major and natural minor scales. Let's start with our first formula!

1. The Major Key/Scales

  • Using C as Starting point: C D E F G A B C
  • Using frets on a guitar: 0 2 4 5 7 9 11 12
  • Using steps: Tonic, Whole-step, Whole-step, Half-step, Whole-step, Whole-step, Whole-step, Half-step
I personally like to the use the numbers or frets on a guitar the most in my formula. How to use it: So take any note, an easy one for guitarist is E. E + 0 = E because we are not going up any frets. This is are first interval, also called our root, bass, or tonic. E + 2 = F# because we went up two frets from the open E. This is our second interval, called the supertonic because it is one above the tonic or root note. E + 4 = G# because we went up four frets from our open E and two frets from our F#. This note is our third interval and is also called the mediant. E + 5 = A because it is five frets higher than open E and one fret higher than our mediant, which was G#. Hopefully this makes senses. If you continue this process starting on E, your key becomes this: E F# G# A B C# D# E. Here are the names of all the intervals in a key:
  • 1st interval: Tonic (Root)
  • 2nd interval: Supertonic (Super means above tonic)
  • 3rd interval: Mediant
  • 4th interval: Subdominant (Because it is a fifth or dominate below the tonic)
  • 5th interval: Dominant
  • 6th interval: Submediant (Because it is a third or mediant below the tonic)
  • 7th interval: Leading Tone/Subtonic (Leads to the tonic and is one below the tonic)
The reason why I am expelling all of this is because in the professional world, this is how musicians communicate with each other and it makes communicating and thinking about music so much easier. That and throughout this article and maybe others I will refer to certain notes as the fifth or third or seventh or the dominant or leading tone and I want to make sure everyone understand what note I am specifically talking about in regards to a specific tonic and key/scale.

So if we are in the key of E major, our scale is E F# G# A B C# D# E. Notice that there are four sharps in our string of notes, therefore in our key signature we will have four sharps or four accidentals. If you start with the first sharps that occurs, the F#, use that as the new tonic and go up to the fifth. That note is the C#, which is sharp. If you treat that as the new tonic and go up a fifth, you land on G#. If you do the same thing again you land on D#. The reason why I am telling you this is because in tonal music, the accidentals used in keys moves in fifths when we talk about sharps and in fourths (or down in fifths) when we talk about flats. Any key signature with a sharp will have at least an F#, so we always start on F# when counting our accidentals. If you are uncertain about what notes are in a particular key but you know the number of sharps, you're in luck! Let's say you need to play five sharps but you have no idea what to play, start on F# and go up in fifths five times. You should come up with F# C# G# D# A#, which means that your key has the folioing notes in it: B C# D# E F# G# A# B and you're playing in B Major.

Now we can do the same thing with flats. Like how when we count sharps we start on F#, when we count bs we start on Bb. Unlike the sharps, we count up in fourths instead of fifths. So if we need to play in a key with three flats we count: Bb Eb Ab and we get the following major scale: Eb F G Ab Bb C D Eb or Eb Major.

Hopefully this all makes sense. You may be wondering how do I know the names of these major scales and which note to start on, Well, when you have sharps, you take the last sharp you counted and you go up one pitch and start on the natural version of it. So a key with three sharps, the third sharp is a G#, so if I go the the next pitch A, our key is A Major. Pretty simple right? Well in flat keys we go to the previously counted flat and that is our major key, UNLESS you only have one flat. If you only have one flat in your key (Bb), then you are playing in F major and F is your tonic. But lets say your have five flats in your key. The fifth flat is Gb but we go back one to the fourth flat, which is Dd, so our key is Db major and our tonic is Dd. These principles can me applied to minor keys and other scales as well. Speaking of minor keys...

2. The Minor Key/Scales

  • Using C as starting point: C D Eb F G Ab Bb C
  • Using frets on a guitar: 0 2 3 5 7 8 10 12
  • Using steps: Tonic, Whole-step, Half-step, Whole-step, Whole-step, Half-step, Whole-step, Whole-step
So if we start on our low open E string again, the notes in E minor would be: E F# G A B C D E.

Now, if you noticed earlier I wrote out the notes in the G major scale. Notice that they are the same pitches that are in the E minor scale, but the scales start on different notes. The E minor scale is the relative minor to G major and G major is the relative major to E minor. So if someone told me to play something with one sharp, I could play in either key or mix the two up. Later one I hope to discuss modes and hopefully this will make more sense. You can usually tell be how a piece of music feels to play either in major or minor. Major keys sound happy, joyful, triumphant, and powerful. Minor keys sound sad, intense, sinister, and dark. To find the relative minor in a major key, go either up to the sixth interval or down three intervals from the tonic and have that note be your new tonic in the minor scale. In a minor scale, you must either go up to the mediant or down six intervals and used that note as your tonic in the new relative major scale.

In tonal music, certain intervals have certain functions. One that greatly affects minor keys and scales is the seventh interval or the leading tone. In a major key, the seventh interval is only a semi-tone or one fret away from the next tonic note. However in a minor key, the seventh interval is a whole-tone or two frets away from the next tonic note. The function of the seventh is to lead into the tonic note after a cadence. I will talk about cadences later, but sevenths lead because they are only one fret away from the next tonic and feel unresolved until they get there. This makes us have to modify our minor scale to be able to play traditional tonal harmonies/chords. There are two other common minor scales used in tonal music besides the minor (also called the natural minor) scale 

A. Harmonic Minor

  • Using C as starting point: C D Eb F G Ab B C
  • Using frets on a guitar: 0 2 3 5 7 8 11 12
  • Using steps: Tonic, Whole-step, Half-step, Whole-step, Whole-step, Half-step, Three Semitones, Half-step
It is essentially the same thing as the natural minor scale except that the seventh interval has been raised by a semi-tone or a fret 

B. Melodic Minor

This one is a little tricky because it involves different notes depending if you are playing the scale upwards or downwards.
  • Using C as starting point: C D Eb F G A B C Bb Ab G F Eb D C
  • Using frets on a guitar: 0 2 3 5 7 9 11 12 10 8 7 5 3 2 0
  • Using steps: Tonic, W-S, H-S, W-S, W-S. W-S, W-S, H-S then down W-S, W-S, H-S, W-S, W-S, H-S, W-S(Now this is the tonic you started on)
So if you are playing up in pitch or up the scale, it is the major scale with a flat third or flat median. However, when you are descending, the scale is the natural minor scale. The reason why this is a common scale is because it allows us to play over minor chords but still use that seventh interval as the leading tone so we can play dominant chords, which I will explain more about later. When we play a minor scale that is not the natural minor scale, we are playing more accidentals that are not part of the key and must be added. If done well though this is acceptable because of the harmonies or implied harmonies that can be created.

So we now know how to figure out what notes are in the major, natural minor, harmonic minor, and melodic minor scales and how to count accidentals in key signatures. We also learned the names of the intervals and the leading tone is important for tonal harmony. We also discussed how there are two different types of keys, major and minor, and how they are related.

Well, I know that's a lot of information to take in at once. Hopefully with this article you can construct the four basic scales that were introduced and play them starting on any one of the twelve notes. You should also be able to calculate what accidentals are in what keys so you can figure out what notes are used in the scale you want to play in. This is only the beginning. In the next article I will discuss more about harmony, chords, and how they tie into everything I've introduced in this lesson. I hope that this makes sense and that t'll help you become a better musician. Please let me know if you're confused about anything at anytime. Cheers!
More mhillips lessons:
+ Tonal Theory Applied to the Guitar, Part 2: Chords, Progressions, and Cadences The Basics 04/23/2014
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