I am playing a song in the key of D (or B minor actually, which is D), but inside of the song, the 2,3 and 6 chords are changing to major chords instead of minor chords. Bm becomes B. E minor becomes E. F#minor becomes F#. Whats happening here? Have i shifted to another key? Is it chord substitutions in some way? is it a mode or something? i'm confused. "Once Upon a December" is the name of the song.
I had a listen to Anastasia and it's very much in the minor. It starts in Bm then modulates up a semitone to Cm, and ends up in another shift to C#m. Adding accidentals within a key adds flavour and interest, but the song is still based in the minor.
By the way, Bm is not D. They simply share the same key signature - two sharps.
Here are the chord changes for the first half of the verse in "Once Upon a December":
Bm F# B7 E Em Bm Em F#
The song as a whole is in
B minor, which is clear just in these chord changes. However, the presence of both major and minor chords can lead to some confusion. Here's what's happening:
Bm: this is the
ichord -- the "home base" chord at which the song most feels at rest.
F#: this is the
Vchord -- were the song to follow the
B minorkey signature strictly, this would be a minor chord; however, it is customary to make the V chord into a
majorchord. Even with the alteration, it is still considered part of the key of
B minor. (As to why that is, I leave for another question.)
B7: this is clearly not part of
B minor, but it's also not part of
B major, even though it has a major sound within it. This chord actually comes from the key of
E, where it is the V (dominant) chord. (Note that the next chord is E). The
B7chord is what is known as a "secondary dominant" (What is a secondary dominant chord?).
E: There are two ways to consider this chord. We could look at the
B7 Eand a (very) brief visit to ("tonicization of") the key of
E major, and that would be perfectly correct. But the better analysis, IMO, is that
E majoris "borrowed" from
B major, making it closely related to
B minor. This technique is called "modal mixture". In either case, the previous
B7chord serves to intensify feeling of movement toward the arrival on the
Em: This is the
B minor. It's an easy-to-hear shift from
E majorand helps our ears adjust back to
As a final point, it's important to understand the
F# chords as the
V chords of
B minor. The Roman numeral designations have meaning about how the chords function within the (key of the) song. To consider the song in the key of
D major would mean that
D is the "home base" sound, and the chords would operate in different ways as
Basically, whenever you encounter a non-diatonic chord, it's safe to assume that something happens with the harmonic feeling at least at that point. The same goes with non-diatonic notes in the melody, i.e. if there are accidentals, unless it's a very short embellishment. Here is a very basic example, where the non-diatonic D chord is used in a C major key context.
The melody doesn't always reflect the modal change, but backing chords usually do. The example above - a "secondary dominant" D major in the key of C major - is so common that many people don't even think about it as any sort of "modal" anything, but the F note being temporarily changed to F# is a small temporary change to the intervals around the tonic. In other words, the 4th scale degree is temporarily raised to an F#, which makes the set of notes the same as in the G major or C Lydian scales. But that change only lasts for the first half of the second bar in the example. It doesn't have to mean any kind of key change, it's just a temporary change in the intervals around the tonic.
Here is the same example transposed to D. The key signature, two sharps, sets the default diatonic scale, and whenever changes are needed, they are denoted with temporary accidentals. The temporary change is canceled out by either the next barline, or an explicit natural accidental.
But the melody or other notes don't necessarily have to utilize the temporarily modified scale degrees, so you might not see any accidentals.
In your example, when there's a B, E and F# major chords when you used to have the D major scale as your set of expected intervals, there's just a temporary change of modal feeling. Depending on how widely and for how long the different modal feeling stays, you might classify it as a modulation or modal interchange or modal mixture. But the term and classification between different theoretical categories doesn't really matter. It can be a subjective gray area, and argueing over what is the "correct" categorization doesn't make you understand it any better. What matters is that you can identify the possible sets of intervals you feel there is in the harmonic context around the tonic at each point.
There is really no way to know exactly what is happening without the melody. If there are accidentls in the melody then clearly there is a key change, even if momentarily. However it could also be an example of a cycle extension. This is very common and also happens the other way, i.e. major changing to minor. As an example the 3 chord is the V of the 6 chord (relative minor), so making the 3 major provides the right harmony to create a resolution to the 6 chord. In All Of Me the changes are C, E7, A7, D-7, in the key of C major. The entire string of chords hints at landing on D minor. The melody also has the G# over the E7 chord, but even if it didn't the E7 would be a nice extension before moving to A (maj or min). Think of all the places the 2, 3, and 6 chord can move to. 2 goes to the V chord, so a 2 Maj would act as the V or V in the original key. The 3 chord is the V of 6, and the 6 chord is the V of 2. You have a circle of 4ths moving from iii --> vi --> ii --> V --> I, and one commonly encounters, III7 --> VI7 --> II7 --> V7 --> I in Jazz rhythm changes. You can even slip them in right before the change,
iii --> (III7, vi) --> (VI7, ii) --> (II7, V)... etc
Even is there are no accidentals in the melody this device can create a lot more harmonic texture to the arrangement of a song.
Going the other way one frequently encounters the Amen cadence IV --> I modified with a iv chord creating a chromatic walk down, IV --> iv --> I.
So the presence of the majors on a minor, or minor on a major can be there for different reasons.