-
Hey @Cadgirl ;
Let me start by saying, yes, you have the correct understanding.
Now, let me clarify the terms, because it is very common now a days to use the terminology incorrectly, which greatly increases the confusion and makes it harder to understand.
So, a “key” is simply a collection of 7 notes and 7 chords. If you stay “in key”, that means all your notes and all your chords are “diatonic”, that is, they stay within those 7 notes and 7 chords.
Now, a “mode” is when you use those 7 notes and 7 chords, the “key”, and pick one of the notes to be your tonal center. Since you have 7 notes, you will have 7 modes. So, using the key that has 6 natural notes and one sharp, F#, your Ionian mode (major) is G. Your Aeolian mode (relative minor, it’s a relative of G major since it’s in the same “key”, or same set of 7 notes) would be Em. Neither G major nor E minor are keys, rather they are scales within a key, the same key. So it is the “key of G”, not the “key of G major”. Again, the “key of G” determines the 7 notes, not which note you use as your tonal center.
One reason this is confusing is because the G is the first degree and we call it the “one chord”, which sounds like we are talking about the scale of G major. However, and this is exactly why there is so much misuse of terms, the note G is the “root” of G major, but it is the “fundamental” of the key of G, not the “root”.
Ok so what’s the difference between a “root” and a “fundamental”? The “root note” is the tonal center, so it’s G in G major, it’s E in E minor, (it’s A in A Dorian, it’s B in B Phrygian, it’s C in C Lydian, it’s D in D Mixolydian, and it’s F# in F# Locrian, all of which are relatives as they are all in the “key of G” with one sharp, F#.)
The “fundamental” is the low note that is used to build the key. So all the notes are related to the fundamental by simple mathematical ratios. That’s why they all sound good together and why the major scale sounds the most resolved.
I hope this mini lesson in theory helps.
MG 😀