I'm a beginner in the music world. So my question may seem stupid and confusing. So I'm gonna elaborate a bit.

Say, I want to write a track in the key of D. So I have the notes D,E,F#,G,A,B & C#. I cannot use any other notes than these. But THE CHROMATIC SCALE suggests the usage of all the 12 notes (all white and black keys). Which means I really can use notes out of key?

So the theory of KEY and the theory of THE CHROMATIC SCALE contradicts each other. I really don't understand what is going on here! Please explain with simplicity like you would teach a 12 year old.

  • 1
    I think an important ingredient in learning to compose is learning to read and even play many kinds of music. The more music you read and play, the more you’ll discover how most music is at least a little chromatic, and it will start to become clear when and why chromatic alterations are used and how others have composed and you can then take ideas from many sources and composing makes a lot more sense. Aug 22, 2021 at 13:58
  • 1
    How is it that this question has five answers and only one upvote? A question that attracts five answers must be a good question.
    – phoog
    Aug 22, 2021 at 22:22

5 Answers 5


It's a good question, and one a beginner may ponder for a long time!

Simple answer involves terminology. Scales are simply sets of notes, ordered ascending/descending. So many (many, many) sets of notes exist - humans love ordering and pigeon-holing - and have done just that. One such scale incorporates all the notes found on a piano - the black and white keys - it's the chromatic scale. Leaving no notes out. So called as it's colourful, and often adds colour to a piece of music by using notes out of the key.

The notes in key are generally, particularly in major keys, called the diatonic notes. That's just another set of notes, that can be put into a scale (the major scale), which work well together, both from a melodic point of view, but also in a harmonic way - take alternate notes from the scale, and they blend together to form chords, which all sound like they 'belong' to that key, and thus are coherent in that piece.

A sort of child-like analogy may be - we have 26 letters in the alphabet, but we never have to use all of them, but - we almost always have to use at least one of the five vowels to make words pronouncable, if that makes sense at all. In fact, in a diatonic piece, we don't have to use all 7 notes to produce a good tune (but they're the go-to notes at least).

Humans not only like ordering, but making 'rules' too! And rules can get broken. At 4 yrs old, we're told you can't take 6 away from 5. At that age, it usually makes sense and is accepted. Maybe it's the same for songs. 'Stick to diatonic notes, and it'll work.' Yes, of course it will, but - sometimes the chromatic notes (the five missing in a diatonic scale) give a piece some extra colour, and an interesting diversion, and can be used.


Here's a quote from the question with the question's incorrect assumption in bold:

Say, I want to write a track in the key of D. So I have the notes D,E,F#,G,A,B & C#. I cannot use any other notes than these.

Key is mostly about the home note. The home note is D. Secondarily, it is about the home chord, specifically, whether the home chord has a major or minor third (in the case of D, whether it includes an F♯ or F♮).

Beyond that, it's a bit vague and maybe even statistical. Most pieces in D major will mostly use the seven scale notes you listed. But that's not the primary condition that causes a piece to be in D major, nor even a necessary one.

If you want to understand key from a historical point of view, start with some music from the early 1600s. Simpler tunes, especially, stay in the diatonic scale. But sometimes you'll have a more complicated tune. The first phrase starts on D but ends on A, then the second phrase returns to D. Toward the end of that phrase, there may be a G♯, which you might think of as having been "borrowed" from the key of A. That doesn't stop the overall key of the piece from being D, however.

These sorts of excursions into other tonal areas became more common and more adventurous over the next few centuries. Other reasons for introducing chromatic notes also arose. For example, where there is a whole step between notes of the scale, you might just fill in that interval by adding the half step between them. That is, a part with the notes A, G, F♯ might turn into A, A♭, G, F♯.

Both of these practices are sometimes said to be "colorful," in that they supposedly add interest or variety to the music, and indeed "chromatic" comes from a Greek word meaning "color."

But THE CHROMATIC SCALE suggests the usage of all the 12 notes (all white and black keys). Which means I really can use notes out of key?


I really don't understand what is going on here! Please explain with simplicity like you would teach a 12 year old.

A piece that is in D major will have a home pitch of D and will prefer to use the notes of the D major scale, but may use other notes for any of several reasons, perhaps because the key center moves temporarily to another note or perhaps just for "color."

  • Thank you. This took out a lot of the vagueness!
    – tahuislam
    Aug 22, 2021 at 20:48

Even if we're exclusively in one diatonic scale, we would sometimes use out-of-chord notes in the melody, e.g. A over a C chord. As long as we approach them properly, the music would sound good (how exactly we do it is something you'll probably learn later on if you continue learning music theory).

Out of chord notes create a temporary dissonance, which gets resloved when the melody goes back to the chord tones. So you can replace an out-of-chord note in the key with a non-diatonic note (usually nearby) and it will serve pretty much the same purpose.

Btw, just because you only use D E F# G A B C# doesn't automatically make your track in D major, it could also be in B (natural) minor, for instance. It would probably be more accurate to say that your track is in D major if the harmonies in your track resolves to D major chord the most. And using notes other than those doesn't automatically mean you're not in D major, either (e.g. secondary dominants).

  • A piece using the pitches of the D major scale could also be in G major. Look at the first half of (the modern incarnation of) the Star-Spangled Banner, for example. The raised fourth scale degree doesn't really make it lydian.
    – phoog
    Aug 22, 2021 at 20:08

The prevailing key (or chord, or scale) of a piece of music is a framework, not a restriction. It can be decorated, it can be distorted, it can be extended. It sets a baseline of normality so that you can do interesting abnormal things!

Here's a simple and very common chord sequence in the key of C major.

C, C♯dim7, Dm7, G7, C.

The second chord is a 'chromatic' chord. It uses notes that aren't in the key of C major. But it doesn't take us out of C major, the framework is intact.

  • I thought that every single tonicization, including the tonicization of D minor that C#dim7-Dm7 pulls off, takes those measures or parts thereof out of the home key (in this case, C major). The tonicizations don't prevent the entire piece from being labelled as being in the home key, but it makes the solidity of that home key in doubt.
    – Dekkadeci
    Aug 22, 2021 at 15:56
  • @Dekkadeci I suppose it's subjective but I don't see chromatic chords like that as changing the key. It's functionally relative to a chord (or even a scale degree) other than the tonic more than representing a different key. Consider for example if over that chord progression your melody is E, E, D, D, C. That's C major, plain and simple, with an interesting chromatic harmony.
    – phoog
    Aug 22, 2021 at 20:21
  • 1
    We can describe the C#dim7 in my example as a secondary dominant, temporarily (VERY temporarily!) tonicizing the chord after it. A chromatic chord introduces the possibility of a modulation. But if it doesn't, it hasn't :-)
    – Laurence
    Aug 22, 2021 at 21:26

There are many songs and tunes that contain just the 7 tones of the principal keys in major or minor: DoReMiFaSoLaTiDo or CDEFGABC and the relative minor keys. (Also many songs are built only on 5 tones=Pentatonic).

A lot of songs are cadencing (half-stop after e.g. 8 bars) on the dominant (which is normally introduced by the V/V=secondary dominant). Even here you need a sharpened 7th as leading tone to the dominant root). But many songs use chromatic approaches (also improvised as a small a glissando by the singer (e.g. blue notes): e.g. the triad of I (somido) and IV (dolafa) can be variied by the soloist like fiso-rimi-tido and tido-sila-mifa, by adding a halftone ahead of the triad tones.

In short: the chromatic scale and the diatonic scale are not contradicting, the chromatic brings more color in the tune and is considered as enrichment and embellishment. You can harmonize this chromatic notes or treat them as passing tones or approaches (Appoggiatura).

Or you can reduce a melody full of chromatic tones to diatonic passages, aswell you can reduce diatonic passages to triades: From Bach to Mozart to Elvis, Conny Francis, or Whitney Houston (I will always love you) aswell in Classical Music, Jazz, Blues or Pop and Folk.




  • thank you for sharing the song man. It's beautiful!
    – tahuislam
    Aug 26, 2021 at 16:35

Not the answer you're looking for? Browse other questions tagged or ask your own question.