Is the difference between key and scales just unordered vs. ordered pitches? [duplicate]

Question

Hi guys I was trying to understand the relationship between keys and scales, from what I understood starting from the basic pitch: A A# B C C# D D# E F F# G G#

if we start from one and take WWHWWWH

we obtain a major scale if instead we do WHWWHW we obtain a Minor scale.

and so far I understand, now from what I understand a key is simply an unordered set of pitch. instead a scale is an ordered set of pitches.

so for example CDEFGABC is the c major scale instead ABCDEFGA is the A minor scale and they contain the same notes, so they shouldn't be in the same key? so should Cmajor key and A minor key be the same?

and in this way I started from the scale and I said since I take the notes of this scale ( for example a C major) i have a C major Key, so to get a key I always have to start from the scale?

Answer 1

It's more the other way round. Any scale is an ordered set of notes which (usually) goes together. True, start anywhere on the whole set (chromatic), and count TTSTTTS (or WWHWWWH), and you end up with a major scale, in the key of whatever note you started/finished on.

Similarly with a minor scale - but only the natural minor, which, if you didn't realise, is the same order, just starting on the 6th note of any major scale.

A key, however is a slightly different concept, as you suspect. Any key will have (and have to have) a root note - which is the note where any tune in that key feels most at rest - home. Properly know as its tonal centre. Your examples of CDEFGAB could actually have seven different notes as the root, or home note, of a key - or mode. The most common key names will be C major or A minor, but could just as well be D Dorian or F Lydian, for example.

The other aspect of a key is which notes it contains. They're called diatonic, and 'belong' to a particular key. Let's take the scale notes of, say, G A B C D E F♯. They all 'belong' to key G major, and when put together in ascending/descending order, constitute the scale of G major.

You find that any set of notes, such as this, are in a key, and so key and scale are related, but not synonymous.