Hi, I have a burning question. A couple of music theory books have stated that the only notes in a song are those notes in the key of that song, barring a few accidentals. This goes for the chords too. OK, looking at songs say in the key of FM, all B's are flat. As I look at the chords in that song I see EMaj, which has a C# in it and I start to see that the rule of the key does not apply. I checked other songs and the same happens. What gives here?
HELP
thanks, frank

Your books must be describing diatonic chords for the key, in which case that woud be correct. Diatonic chords are made up of only notes within the key of the song.

However most composers don't limit themselves to diatonic chords only.

Thanks Joe. So most if not all the songs I'm practicing are not diatonic songs.
frank

E major doesn't have a C# in it, unless it's an E6 chord. Chord tones are E-G#-B. But yes, in the key of F major, E is not a diatonic chord (because of both the G# and the B natural). Probably what is called a secondary dominant. Is the next chord A minor? That IS a diatonic chord in the key of F and the E major is probably an approach chord to what is after it.

I should never type without my glasses on, sorry. It was an AMaj with a C# then latter there is a EMaj with a G#. Funny, I checked another theory book and they say the same: Only those notes and chords in the key of the song are allowed. So much for theory.
frank

Any theory book that describes something as being "allowed" or not is doing you a mischief. Music theory is a 100% descriptive endeavor, not prescriptive at all (at least for music written in the last few hundred years).

The biggest "exception" is in the minor keys, because the V chord needs to be major. So for example in Gmi (2 flats) you see an F# because the 5th degree of the Gmi scale is D. To make a D major chord you need to have the F#.

Another one is the 7th, when the composer uses the somewhat more common dom 7th that that is lowered a half step vs the major 7th that is not. For example in the key of C, no sharps or flats, you see a Bb often for the C7 vs the CM7 with a B natural.

Hope this helps.

And this song is in the key of F (major)?

What is the name of this song?
Do you have a copy that we can look at?

Actually 2 common chords in jazz. Secondary dominants. A major is the more common one (second chord in "Georgia On My Mind"). Usually followed by the 6 minor chord (Dmin in this example).

The other one, E major, is less common but still widely used, mostly as an approach to the 3 minor chord (Amin here).

These serve as secondary dominants, but can be played with or without the seventh.

No! A RESOUNDING NO!! Unless "Music Theory" has been dumbed-down like so many other areas of study, here is the real, over-arching thing you need to clarify.

Could it be that these "Theory" books are on beginning Harmony, and the author is placing the diatonic restriction on the 4-part writing for starting out?

Could it be that you are interpreting incorrectly? (Maybe without the glasses?)

If you let us know which music theory books you are consulting, perhaps we can clarify. And if not, we can recommend a REAL Theory book, like the Walter Piston text.

Ed

The first harmony books give a simplified general outline of how music works. Real pieces are more complex. Only one of my harmony books has examples from real music, and they isolate a few measures from this and that piece, being careful not to include anything that doesn't fit the rules.

The simplest music will use the notes of the key, and chords that are built on those notes. But other notes are added to make a melody more interesting, or to give chords more interesting color. Music also modulates to other keys. For example a piece that starts on C major may be in G major in the middle without the key signatures changing, and then go back to C major. You'll see F# and the D major chord, even though they don't belong to the key of C.

It's like in grade 1 we learn that "a" says "a" in "cat" and "nap", and then taking a book off the shelf and seeing "caught" and "abatement". The theory books only give us a part of the picture, one thing at a time.