What is a Key in Music?

It’s important to understand exactly what a key in music is and what it does. However, if you were to say to someone, “What is a Key in Music?” they would probably know, but they might find it hard to explain.

A Basic Understanding of a Key in Music

The simplest definition of a musical key is a group of notes around which a piece of music revolves. It can be based on a Major scale or a Minor scale.

Songs in a Major Key

For example, music in the key of C major is based on the seven notes that make up the C major scale. Those are C, D, E, F, G, A, and B. They are the fundamental notes that constitute the melody of the song, as well as everything else within the song, which are derived from those seven notes.

Songs in a Minor Key

Let’s take a look at a piece of music using D minor as an example. A song in this key will feature the notes that make up the D Minor scale – D, E, F, G, A, Bb, and C.

The Musical Center of a Key

The center point of any key is the root note. When we are discussing keys, the Tonic is the name of the root note of a musical key. In a similar way to the root note of a chord, the root note is what a scale is built around. To give a couple of examples, the root note of a C major scale would be C. The root note of the G major scale would be G.

Many Happy Returns

Listen to most music, and you may notice that wherever it goes, it always wants to return to its root, to the Tonic. It feels like it brings the music to its completion. The Tonic is the center of the key.

What can make music interesting to the ear is the way it moves away from its tonic resting point. It seems to keep us waiting, at times endlessly, but it always “comes home.” The Tonic is calling.

Without the Tonic

You can hear it in various parts of songs, the music wanting to come back to its root. It is most noticeable at the end, possibly the final chord, or a coda. It became a “thing” to not finish on the tonic but instead end on another note or chord.

I have to say I am not a big fan of that. It lacks the resolving effect of an ending. I understand that is the point, but it doesn’t feel like it leaves the music in a complete state. It may well be that the reason is most of us have a built-in sense of tonality.

What is Tonality?

On the subject of tonality, let’s take a quick look, as it is relevant to the Key. If music has this centered organization around the Tonic or root note, it is said to be “tonal.” The vast majority of the music we listen to is tonal.

When music does not have that tonal center, we call it “atonal.” This is not as pleasing to the ear, and therefore, not very popular with most people.

How Many Musical Keys Are There?

As we have twelve major scales, so there are twelve major keys. There are also twelve minor scales; hence there are twelve minor keys. With a little math, we can see that 24 is the total number for musical keys to work with.

Three of the keys can be identified in different ways, though. They can be given names with sharps or with flats. They are exactly the same notes but just identified differently.

For example, the key of F# major and Gb major have the same notes. But they are written in different ways.

Written in F# major as F# – G# – A# – B – C# – D# and E#.
Written in Gb major as Gb – Ab – Bb – Cb – Db – Eb and F.

The same notes are just written down in different ways. There is a reason, and at times, one way of writing the key down is preferable to the other.

Can you only include Notes that are within a Key?

The majority of the notes you use will center around the notes of the key. However, you can stray outside. These notes are unsurprisingly called “outside of the key.”

These notes are often used but with care. If you use them wrongly, the tonality of the song will disappear, and it will be unpleasant to listen to.

Where Are “Outside Notes” Commonly Heard?

Experienced musicians have learned how to use them to great effect. And this applies, especially to Jazz. You will hear these ‘outside notes’ in Jazz solos, but they are used in such a way as not to upset the balance of tonality.

That is not to say that at times they don’t go close because they do. But they are not limited to Jazz. You may hear them in Metal riffs, Grunge, Progressive, Hardcore, and even some pop songs. This is another reason why when people try to answer, “What is a key in music?” a straightforward response is not always easy to come by.

Let’s Explore a Little Further

We have seen how a key is centered around the seven notes that make up the scale. And we have discussed how major and minor keys and scales are slightly different. But there are major and minor keys and scales that share the same key signature, i.e., the same notes.

A Relative Minor Key

Each Major Key and its scale have what is known as a Relative Minor key and scale. They have all the same notes, but the difference is that they start on a different Tonic, therefore even though they are in the same order, they have a different series of tones and semitones that separate them.

Because the notes are the same, they, therefore, have the same key signature. They are said to be “enharmonically equivalent.”

How Do You Find the Relative Minor Key From a Major Key

For example, in the Key of C, take the root note, or Tonic, and count down three notes. That takes you from the C to an A. The A is then the Relative Minor. So, C is the major key, and the Relative Minor with all the same notes, but starting on an A is A minor.

For G major, counting down three takes you to E. So, the key of G major has a Relative Minor of E minor. The same applies to every key. Every major key has its relative minor. They are said to be in a relative relationship.

Minor to Major?

The same applies in reverse. If you have a Minor Key and want to find the Relative Major, just go to the tonic and count up three notes. That will give you the major key relative to the minor key you are in.

So, if you are in E minor and want to find the Relative Major key, counting up three takes you to G. That will be the relative Major.

Confused?

Don’t be. We have seen that a musical key is a group of notes that are the foundation of a musical piece. The majority of those notes are from one particular scale. This is where we get the name of the key.

Therefore, if a song is using notes from a scale of C major, it is likely the song is in the key of C major. There will be no sharps or flats in the key signature displayed in the sheet music after the clef sign.

As we have just seen, the relative minor has the same notes as C. Therefore, the Key of A minor would also be shown in the key signature with no sharps or flats.

How do you tell the difference?

The easiest way is to look for the root or tonic note. We talked about the tonic note as being the home note or chord, in other words, where the start and finish are most comfortable. Just look at the music.

If it starts and ends on the tonic, then there is a good chance that is your key. So if the music starts or ends on C, then there is a good chance that the Key is C. Not always the case, of course, but it is a good start.

Understanding the Basics of Keys and Scales

This is an important part of understanding music. Here are some materials to help.

Want to Know More about Music?

Our experts are ready to share what they know. Have a look at our in-depth articles on The Bass Clef, The Tenor Clef, The Minor Scales, Relative vs Parallel Minor, Diatonic Scales, Types Of Bebop Scales, What Is Negative Harmony, What Is a Major Chord, and A Complete Guide To Major Scales for more useful musical information.