Danny's Song key question
 

This is perhaps a music theory question. I'm learning to play Danny's Song by Loggins & Messina. The song starts out with 4 bars of D. I think this normally establishes the key of the song as D major. When I look at the chords in the song, I see
D C Bm E7 A G
I recognize the D Bm A G as belonging to the key of D, but not the C and E7. Am I correct in saying that this song is in the key of D major, and is there a term for the chords that are outside the key of the song?

The last chord of a song is often the key of the song.

I think I play Danny's song the same as L&M and I play it in D. So from my experience yes it is in D Major.

Danny Boy is very old traditional. I'd say it's in whatever key you want to sing it in.

Danny Boy is a different song. This is about Danny's Song, a folk/pop hit from the 70's by Kenny Loggins and Jim Messina.

Is there a term for the out-of-key chords, like passing chords, or secondary chords, or are they simply called out-of-key chords?

Oh, right, sorry. :wild:

Yes. 99% of the time - in rock - if the first 4 bars of a song are all on the same chord, it's a safe bet that's the key.

There's still that 1% though... And in jazz and older pop, it's a lot more than 1%.

The real key of the song is whatever chord "sounds like home". That's why - as love the guitar said - the final chord of a song is a safer guide. Provide the song has a clear final chord that sounds final.

A famous example of a song that neither starts nor finishes with the key chord is Waterloo Sunset. It starts and ends (fades out on) the V chord. But you can hear how that opening chord resolves to the key chord when the vocal starts.
There is. Outside chords tend to come in two categories, and this sequence (neatly) has one example of each.

C is a "borrowed chord". It's an example of the rock convention called "mode mixture", or "borrowing from the parallel minor". A major key will commonly have a bVII chord (like this), and might also have a bIII or bVI (F or Bb in this key), even a minor iv (Gm in this key) - which all come from the "parallel" key (D minor).

E7 is a "secondary dominant". Labelled as "V/V", which means "dominant of the dominant". A key can have up to five secondary dominants, and V/V is the most common. As you can see, it leads directly to the V chord, A. Compare with how it sounds if you use Em or Em7 instead, and you'll hear the secondary dominant effect.

JonPR, really awesome answer. Thank you!

Nailed it. Secondary dominants can be used to completely change key (modulate), or to create a temporary shift of key center, as it does here. Also note, Bm E7 A creates a sneaky little ii-V-I in the key of A. That wouldn't happen with an Em...