Justin’s Quick Guide to Basic Music Theory and Playing by Ear

Version 1.0

(note: not responsible for use of inaccurate information in this handout; this is NOT a comprehensive guide to music theory)

If you are reading this, you must have a) taken the class, Learning to Play Pop (as opposed to Coke), or b) somehow stumbled upon this sheet of paper. Here, I will sum up what was taught in class. If ever you have any questions about what was covered or have future questions about music and guitar, I will do my best do give you a good response if you email Also, please email if you find any errors in here. I love to learn from my mistakes!

I. Scales (not the fish kind)

The Western chromatic scale is made of half-steps or semitones and consists of 12 “steps.” On a piano, one would play all the black and white keys and on a guitar, one would play one fret after another. To play a major scale, one would use the sequence, WWHWWWH. W represents “whole step” which consists of two half-steps or semitones. H represents “half-step.” To play, for instance, the A major scale, start on an A and go up the scale using the sequence. Spelling out the chromatic scale is the best way to visualize this. Then, it is easy to see that subsequent scales are mere shifts of the WWHWWWH sequences, just starting at different notes.

ii. Diatonic triads

Now that you have the knowledge of what a major scale is, we will be able to form chords, or diatonic triads, which fit in the correct note sequence of a scale. A chord, very simply defined, is a root note, the note that names it, a third, and a fifth. Once again, it is easiest to visualize the triads when one spells out the note names in the scale (CDEFGABC, for instance, in the C scale). To find the I (“one”) chord, start at the first note in the scale, and then pick the third and fifth note subsequently in the scale to find the three notes which define the I chord in the C scale. The I chord in the C major scale would consist of CEG. Similar to the method in finding other major scales, to find the remaining diatonic triads in the scale, start on a different note and just shift over. When you are finished, you will have 7 diatonic triads, one for each note in the scale.

iii. Major, minor, diminished, and roman numerals

The proper way of notating these triads is with roman numerals (I, ii, iii, IV, V vi, vii°). You may wonder why some are upper and others lower case and even why one has a degree symbol. Upper case represents major chords. Lower case represents minor chords. The lower case with degree represents diminished chords. So, the I IV V chords are major, and likewise as you look at the notation of the remaining chords. What is a major chord?

The distance, so to speak, between the root and the third will be four half steps and the distance between the third and fifth will be three half steps. A minor chord flips this relationship around. Thus, between the root and third will be three half steps and the distance between the third and fifth will be four half steps. Finally, a diminished chord has three half steps between both the root and third and the third and the fifth.

IV. Intervals

As you may observe, this business of x whole steps and y half steps tends to get a bit wordy. Fortunately, there are established names of these intervals, or number of half steps, between notes. From smallest to largest, here are the interval names in order, starting from the interval of one half step: m2, M2, m3, M3, P4, TT, P5, m6, M6, m7, M7, P8 (“m” denotes minor, “M” denotes major, “P” denotes perfect, “TT” denotes tritone, which is either a half-step above P4 or half-step below P5). As you will notice, each of these interval names correspond to a note in the chromatic scale.

Now, we can make the business of defining chords a bit easier. A major chord now is a chord with an interval of a Major 3rd between the root and third and a minor 3rd between the third and the fifth.

The best way to remember the intervals, in terms of ear training and interval recognition, is to find a familiar tune or song that has the same interval. The purpose of the association is that if you can reproduce a familiar tune or song, you can connect that to the interval associated with it.

V. Inversions

Being the inquisitive musician you are, you may have been thinking as I was explaining the chord, in terms of root, third, and fifth. You may have wondered, “what if I started with the third, then the fifth, and finally the root, what would happen? Would it still be the same chord?” Well my friend, I have an answer for you. Yes and no. It is the same chord in the way that its composition is still the same, but different in that it has a different bass note. This is what we more affectionately call, inversions.

A chord with the third has the lowest note, the fifth, and then the root is a chord in first inversion. And furthermore, a chord with the fifth has the lowest note, then the root and finally the third is a chord in second inversion. The chord with the root as the first note is just the called the root inversion.

Musicians use inversions to add variety to songs. With a trained ear, you will be able to recognize, for instance, that the chord you are hearing is a D major chord, but with an F# as the root. Many times inversions are used so that the bass line goes a certain way without making the song sound out of key.

vii. Do you hear what I hear?

Phew. Finally. He’s done talking about all this and now I can learn about playing by ear! Like many things in life, ear training takes practice. Nothing more to it. Granted, maybe you don’t feel that you have a sense of pitch or musical awareness. Now, I haven’t done any research on any of this, so I wouldn’t want to say that anyone can acquire a good ear, but at least try.

Ok. Pick a song you want to learn. Hopefully it is a song suited for guitar or a song that you’ve seen someone play on guitar. There may be some more complicated techniques and theory to learn, but everything you’ve learned should help you be able to decipher a plethora of songs.

If possible, turn up the bass so that you can pick out the bass line easily. Now is when your patience will be tested. The first step in figuring out the chords in a song is knowing what the bass line is. Some songs will have very simple and repetitive sequences and runs. Some won’t. If you don’t have much experience in interval recognition, it will be difficult at first. However, do not fret! It takes practice. That’s all I can say. The rest is up to you.

Find a way that is easy for you to keep track of the bass line. Whether it just be by memory, or standard notation. One way I’ve found easy to keep track of the bass line is just using the numbers one through seven to represent the pitches in the scale. Instead of CDEFGAB, you would have 1234567. And for any notes that aren’t in the scale, just use # for sharp, or raising a note a half-step, or b (a poor attempt at a flat sign) for flat, or lowering a note a half-step.

Once you have the bass line of the whole song, you task at hand is much like a musical puzzle. You have the relative pitches of the bass line; now find the actual pitches, through whatever means. Once you have the actual pitches, you have the pieces of the puzzle.

The puzzle may be easy to solve since it may scream “key of Cb!!!” If it is, jump up and down and do a happy dance. If not, you will need to put some more time into analyzing it. Recognition of keys takes practice. With enough practice, you will be able to tell the difference between your car keys and your house keys in a jiffy! (wait…nevermind). Those tricky musicians will sometimes throw in bass notes that aren’t in the key. If so, try to isolate those out of place notes and figure out the key from the remaining notes.

If you are really patient and have a lot of time, you can also guess chords around the bass note you are investigating. For instance, the note, E, is part of many chords. Other than the E major chord, it is part of the A major chord and C major chord, just to name a few. You can rule out some of the candidates by realizing that a certain chord fits in the key and another one doesn’t. Then again, those musicians sometimes purposely place chords out of key.

You can either figure out the key first and then apply the rules of diatonic triads to figure out major/minor or you can just play it by ear. In laymen’s terms, major chords usually sound “happy” and minor chords “sad.” However, this may not always apply. Once again, with practice, you will be able to assume that, for instance, the sequence E, D, C is represented by E minor, D major, C major (this is true for many instances, but not a guarantee. Also, to be consistent with tab books and such, that chord sequence in shorthand would be “Em, D, C”).

vii° Closing remarks

Congratulations! Now you have passed this course (Pomp and Circumstance playing in the background). If you take one thing from it, it is practice! There are a lot more things involved in playing songs from your favorite artists, from more in depth theory to actual guitar technique. We only skimmed the surface today. You can never stop learning. I hope you’ve gotten something out of this course. It is really difficult to stuff all this into two hours of class. This class could have gone on for hours and hours. Well, that’s it. Buh-bye!

Here is a place for you to take notes! Grace notes, sixteenth notes, post it notes, whatever you feel like writing down that I go over in class!!!