eli5 Music Key


I often see musicians say something like performing in the key of G. Since they use many different notes while performing, what does this really mean?.

In: Other

Music is divided into keys as you know. We have sequences of notes that we call scales that follow a specific pattern of note intervals (the distance between 2 notes). The easiest and most well-known scale is the C major scale: C,D,E,F,G,A,B,C. Every scale uses all of the note names, but sometimes they are slightly alters with sharps (a half step up) or flats (a half step down). The key of a song depends on what notes and alterations it uses. The notes in a song will primarily match up with the notes and alterations within one particular scale. That scale is the same name as the key. So if a song uses the notes A,B,C,D,E,F, and G or any combination thereof with no alterations or even a few here and there, then it uses all the the same notes as the C scale, so it is said to be in the “key of C”.

In Western European music there are 12 different chromatic notes. These notes are all a half step apart from each other. By arranging these notes from lowest to highest in a series of whole steps and half steps we create a scale. A key is basically a signature that tells you which scale is used to determine what notes are used in the song.

So, if a musician says that a song is in the key of G major, that means the song uses the G major scale as a basis for picking what notes are in the song. That means that the song uses some combination of the notes G, A, B, C, D, E, and F# to create its melodies and harmonies.

Hope that helps.

A “key” in music is a set of notes within the overall musical note tones scale. The key a song is set in also tells you the specific sharp and flat notes to expect by default.

There are 12 notes, at least in western style. Each note is considered a half step apart. In a scale key, when a half is “skipped” it’s called a whole step. Let’s look at C, the easiest one.

>C, D, E, F, G, A, B, C

There is no E#, neither is there a B#. Now let’s look at B.

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

See all those sharps (#)? Since B is just a half step from C, the rest of the notes will also be a half step down. When you play a note that isn’t in the scale, it’s called an Accidental. So for the key of B, if you play an F, that’s an accidental. It normally sounds off but it can make a certain tune very good depending on how it’s used.

If you’re in G, it’s like the G major chord is your home base. In simple songs, and even fairly often in highly sophisticated pieces of music, things will often all begin and/or end on a G major chord if you are in the key of G major. Even if a song doesn’t begin and end on a G major chord, if the song is in the key of G major then G major will still “feel” like “home” to both the players and listeners.

If you’re playing with other musicians, it’s pretty helpful for you to all collectively know that G major is the home base as you execute the song as a unit. That’s because everyone will consequently know that the G major chord is the “home base” chord and that the G major scale is the “home base” scale for the song being played. Feel free to stop here, but just to get a little more in-depth in case that wasn’t enough:

G major (or any major or minor key, for that matter) implies 7 specific chords relative to that key AND a scale (the G major scale, in this example). Those 7 chords are the basis for the harmonies (aka chords used) in the song. The scale is the blueprint for those 7 chords as well as a source of melodies, solos, riffs, drones, bass parts, etc. to be used in the song at the performer/composers discretion.

Not to be too confusing, but to address the “many notes” part of your question: there are several common deviations from the 7 chords and eponymous scale implied by any stated or implied major or minor key that seasoned musicians know to sort of expect from experience and listening.