Music Theory You Need, Especially if You Don't Read: All About Keys

Music Theory You Need, Especially if You Don't Read: All About Keys

August 24, 2018 2 Comments

Even if your band plays exclusively by ear, you won't last long if you don't understand Key theory. The first step is understanding there are twelve keys in Western music (plus three enharmonic keys that are sonically identical to one of the twelve). Each of these keys can be understood as a group of notes that share a common tonality. Can you say, "Plays well with others?" In order to have any idea which notes to play in a given piece of music, you need to know the diatonic scales and chords that make up that particular key. But how do we determine which scales and chords belong together? With the road map that follows, you will be well equipped to navigate without ending up in the wrong key.
Key Signatures

Have you ever noticed that the black keys on a piano appear in alternating groups of two and three, respectively? That is because the formula for the diatonic scale has two whole step intervals, one half step interval, three whole step intervals, and one more half step interval. The black piano keys rest between these intervals in a C-diatonic scale. If you play only the white keys, you end up playing in C major. In the following diagram, notice the key of C has no sharps or flats.

Key of C


Circle of Fifths


In each key, the diatonic scale begins on the tonic (or first scale degree) of the key, then follows the same sequence of intervals. So if you wanted to determine the G major scale, you would start on G and add six more notes, being sure to add the single sharp in the key signature: G,A,B,C,D,E and F#. The key of D has two sharps, so it is written: D,E,F#,G,A,B and C#. As you proceed clockwise around the circle of fifths, each consecutive sharp key adds another sharp in a pre-determined order. Traveling the opposite direction from C, you get F major: F,G,A,Bb,C,D and E. The great thing is that when you build a diatonic scale, all the notes fit perfectly into the key in which you are playing.

Notice that between the sharp keys and the flat keys, there are three overlapping enharmonic keys that have the same notes but two different names.

Diatonic Chords in Each Key

If you build a 7th chord starting on each degree of the diatonic scale, you will arrive at the diatonic chords which belong in that key. These also have a pattern, starting with a major chord on the tonic and proceeding according to the following formula: Cmaj7, Dm7, Em7, Fmaj7, G7, Am, Bm7b5 (key of C).

C Major

Notice in the illustration, capital Roman numerals indicate major chords and lower-case numerals indicate minor chords. To arrive at the diatonic chords in a given key quickly, write out the scale, then add the chord designations after each note. D major would be: Dmaj7, Em7, F#m7, Gmaj7, A7, Bm7, C#m7b5

This can be very useful information. Knowing the chords that belong to the key you are in makes transcription and songwriting much easier. You already know what is going to fit. "But lots of songs have chords outside the diatonic structure," you say. "What about those cases?" The old adage, "You have to know the rules before you can break them," applies quite well. Sometimes great music is built upon the unexpected. But without the expected, what would that mean? Of course, once you have built a progression based upon diatonic chords, you can play the matching diatonic scale over it.

No matter where you play, understanding key signatures and the diatonic scales and chords that comprise them will make jamming, songwriting, and transcription much easier tasks. And when you do choose to play "out" you'll know how to find your way back. In our next installment, we will learn how to use the Nashville Number System to communicate chord structure in any key with ease, as well as how to build your own chords and arpeggios from scratch.

Meanwhile, get some staff paper and write out all fifteen diatonic keys, their diatonic scales and chords. Before long, you will know your way around enough to say, "I can play it in any key!"

2 Responses


August 27, 2018

Good information. I can’t believe how many times I’ve been playing with an “unseasoned” musician and called out I IV V in G and they have no idea what I was saying. Learn this stuff! From a 50+ yrs pro/semi pro.


August 27, 2018

Excellent idea to try and educate your mailing list.

Leave a comment

Comments will be approved before showing up.

Also in Guitar / Bass Amplifier Info & Education

Music Theory You Need, Especially if You Don't Read - Counting Time
Music Theory You Need, Especially if You Don't Read: Counting Time

August 17, 2018 2 Comments

Learning to read music isn't especially difficult when compared with the skill, knowledge, and nuances required to play a musical instrument. Primarily it is a skill developed by practice and repetition, accompanied by a knowledge of the necessary music theory to understand it. Nevertheless, there are vast cohorts of musicians that eschew reading, preferring to play by ear. Depending on your style and background, you may be one of the many great musicians who have learned to play entirely by ear or who use written music as a transcription and study tool, but not during live performance. But having an understanding of the underlying theory is essential to communicating with other musicians in all styles. This series will cover the basic essential music theory you will need to function with competence even if you never learn to read music.

Read More

Five Simple Studio Tips
Five Simple Studio Tips

August 02, 2018 5 Comments

The recording studio is a different beast than the stage in many ways. You are often paying for your time there, and as such, and are expected to come prepared and work efficiently (unless, of course, you have a home studio or your label is paying for your album to be made).  But whether you are a studio veteran or a new musician, there are certain things to keep in mind to help your studio experience go as smoothly as possible.

Read More

How to Keep Your Gig: Eleven Secrets
Eleven Secrets to Keeping Your Gig

July 18, 2018 1 Comment

In our recently concluded series, "How to Get a Gig," we learned a systematic approach to building and marketing a band. We saw how to win gigs by relationship building even if you aren't a born salesman. But what happens when you get the gig? We have all heard how competitive the music business is, but what can we do to stay on the winning side of that competition? What are the secrets that the longest-lived working bands know about staying relevant? This week, we will look at Eleven Secrets to Keeping Your Gig.

Read More