Music: Practice & Theory Stack Exchange is a question and answer site for musicians, students, and enthusiasts. It only takes a minute to sign up.
Sign up to join this community
When I search for keys for various songs online I see that it's the minor scale. But they don't say which minor scale.
For example, if I search for "greensleeves key" in google I get back "E minor" https://www.google.com/search?q=greensleeves+key
So my question is what is the "default" minor scale? Is it the harmonic, the natural, or the melodic, or something else? When a website leaves out which type of minor scale, which one do I assume it to be?
It's not really correct to say that a song is in a "minor scale". You can say it's in a "minor key". But melodies in minor keys tend to use a mixture of minor and major sixths and sevenths (Greensleeves does, at least as I know it). They don't necessarily stick to a single scale throughout.
For the purposes of reading and writing such melodies, you usually use a key signature that allows writing the natural minor without accidentals. (So, in the case of E minor, the key signature with just F#.)
Also note songs don't necessarily have fixed keys--you can play Greensleeves in any (minor) key you'd like. Sometimes a song is traditionally associated with one key, but even then individual performers might transpose the song, for example to make it fit the range of their voice better.
A minor key is just that - a minor key. Scales associated with a particular key have, unlike the major key, options. You are already aware that there are 4 distinct scales used in minor keys - natural, harmonic, classical melodic, and jazz melodic. All have changes from each other involving only the 6th and 7th notes. the reasons have been aired for a long time - plenty are on this site.
Often, a piece in a minor key will stick to notes from a particular minor scale, but others slide in and out of the available combinations. Bear in mind also that minor will include minor modes, which help muddy the waters.
So the writer cannot say which minor scale a piece is in, because a scale is not a key - in minor. Greensleeves is a particular example, and has two versions (at least!) of scales involved, both of which could maybe be pigeonholed as 'this is xyz minor'. But there's little point. In a way, it's like when a major piece modulates, there'a a non-diatonic note involved. Is it absolutely necessary to label everything? I think not!
The phrasing of this question seems to be generating a lot of discussion about the difference between a key and a scale. First, I'll address that issue, and then I'll offer an answer with some references.
I think much of the discussion about key vs. scale is misguided because keys are based on scales. For example, Wikipedia states:
In music theory, the key of a piece is a group of pitches, or scale upon which a music composition is created in classical, Western art, and Western pop music.
If keys are based on scales, then a minor key must be based on a particular minor scale. So the question is valid in asking about the underlying scale on which the minor tonality is based. I see the question as being: is there a single minor scale that is implied when a song is stated to be in a "minor" key?
The answer to this question is: in general, yes, a single minor scale is implied. Stating "E minor" implies E natural minor. For example, studybass.com states:
Similarly, a piece of music can be in a minor key and revolve around a natural minor scale. For example, a song in the ‘key of D minor’ uses the notes of the D minor scale – D, E, F, G, A, Bb, and C.
Furthermore, the same Wikipedia article from above states:
A key may be major or minor. Music can be described as being in the Dorian mode, or Phrygian, etc., and is thus usually thought of as in a specific mode rather than a key.
So even the Wikipedia article straightaway excludes Dorian minor as a key, implying that a different minor scale must serve as the basis for minor keys. This affirms the general position on studybass.com that a single minor scale is implied by a minor key.
This approach might seem to leave no room for keys based on other minor scales--the Wikipedia article states as much. However, there is still a way to describe a song written in a Dorian mode, but that description shouldn't include the word "key." A statement along the lines of "the song is in the key of E minor" implies E natural minor. Perhaps a song written in E melodic minor would be best described this way: "the song is written using the E melodic minor scale."
There isn't a default minor scale, but if we are looking for some kind of foundation idea for minor (mode, key, tonality, etc.) we could say a mediant that is a minor third above a tonic is the primary identifying characteristic of minor tonality.
Beside the tonic and mediant all the other scale degrees are flexible in their exact interval above the tonic. In actual practice minor key music will exploit several options for these flexible scale degrees. You could regard the natural minor scale as the default scale from which scale degrees are altered, but this might be misleading for two reasons: first, it seems to dodge the main issue about the fluid nature of minor tonality, second it doesn't seem to match history. Minor keys in the Baroque era used a key signature that would be equal to the dorian mode. Is dorian mode the default minor scale?
It may be best to embrace the fluid nature of minor tonality. A seven pitch default scale just won't give us a complete picture. Maybe an analogy from science would be useful. Compare theories of the atom: the theory of an electron cloud based on probability versus the old Bohr model of fixed electron shells. Sometimes we just deal with things that are indefinite.
First of all, as other people have already stated, a song is in a key, not a scale. Also, many songs move to or at least allude to several different keys. When a song is written in a minor key, it will often switch between harmonic, melodic, and even natural. Melodic minor will sometimes be used on ascending scale passages, and natural minor is rather rare because its leading tone is not raised, which means that it doesn't naturally lead to tonic. However, harmonic minor is the most-used form because generally speaking it sounds the best to most Western listeners. This is because the leading tone is raised but it is still distinct from major, and it remains the same whether ascending or descending.
