-
So first of all, @campfire , we need to understand what Tony means by “key”. Since almost no one understands what a key is, or at least they ignore what they know and propagate the MIS-use of the term key, it makes this search a little bit of an investigation.
So forget what “key” really means, and recognize that almost everyone means what diatonic scale, or mode the piece is in. And what THAT really means is, what note are we using as our home, our tonic, our tonal center.
So all Tony is really asking for is “D”. That’s the tonal center.
To go beyond that is to open up a discussion of music theory. Tony likes to avoid that as it usually causes more confusion than enlightenment. And part of the reason for that is because of the misuse of the term “key”. Of course, that’s just part of it. Then there is the total misunderstanding of modes. The “key” of C is not the same as C major. C major is a mode. A minor is a mode. And therefore, we can now eliminate the silly argument of whether A minor is a key. Of course it’s not. And neither is C major. They are both in the “key” of C. In the key of C, C is the fundamental, not the tonal center. In C major, C is the tonal center.
This all becomes even more confusing since this Thursday’s chord progression is not diatonic, that is, it doesn’t stay in a single “key”. Best guess since there can be different interpretations, is the key of C. That means I agree with @Bill_Brown that the mode is D Dorian. But another possibility is to call this the key of G and so this is D Mixolydian. Either way, he’s clearly not using the chords of D major (Ionian) and so it has a “modal” feel. Also, he’s using both D major and D minor, which automatically will give a feeling of modulation (changing keys).
So, let’s remember who we’re talking about: Tony. I’m quite sure all he wanted was to identify the note and/or chord that is being used as the tonal center. That’s why “playing by ear” is so superior to music theory most of the time.
Remember that music theory is simply a set of terms and definitions that allow us to analyze and talk about our music. This chord progression was derived by trial and error to find what sounded right for the song. Not by deciding a key and a mode and variations there of.
So when an instructor on YouTube, who’s analyzing a George Harrison song, says George did this or that because… they’re full of dog do do. George was listening to the sounds of different chords as he came up with his song. He wrote his songs like pretty much everyone else, by ear using trial and error. What sounded good. Period.
There are people who write songs using theory, and those songs sound like that. They never make it to pop hits for a reason.
MG 😀