Changing keys within a song

[JackH]

I've been trying to learn a little more theory recently and I think I remember reading about the chord used to change a key up a half or whole step falling under a "theory rule" to remember. Something like the chord needs to be in both keys or something like that. What I think I read may be more of a guideline than a rule.

"My Sweet Lord" (G. Harrison) changes keys. I can play it but I don't "understand" how the theory part works. If I were to learn a song in one key then want to raise the key a whole step I don't know what I'm doing.

Any help is appreciated.

Jack

[stanron]

There is not one single rule for all key changes but somehow or other it works if you can get to chord V of the new key at the end of a four bar cycle. How you get to that chord will change with different combinations of keys. Experiment.

[JackH]

Originally Posted by stanron

There is not one single rule for all key changes but somehow or other it works if you can get to chord V of the new key at the end of a four bar cycle. How you get to that chord will change with different combinations of keys. Experiment.

That seems to be how "My Sweet Lord" works. Starts in A, then gets to E using the B7 (V chord of E key). I think I have the keys right. I also get confused when the minor relative key comes into play.


I'll play with this in a few songs. Thanks.

Question:
Which came first? The music or the theory?

[stanron]

Originally Posted by JackH

Question:
Which came first? The music or the theory?

The music of course. The music always comes first.

[Zandit75]

I'm certainly no expert, but I've never come across a song that jumps so far up the chart(From A to E).
Coming from a Country singing background, most songs that I have sung with a key change is normally from neighboring keys mostly G to A. I sing one song that is in A for the verse, but jumps down to G for the chorus each time. It's weird, but it works for that song.

[JerrysGuitarBar]

My Sweet Lord moves from the key of D to the key of E by inserting, as you say, a B7 chord (dominant of E). He does it in a beautifully smooth progression D - D7 - B7 - E.

Other songs will just wrench you into the new key - which can also be effective - like Alan Jackson's Remember When which has to get from the key of C for the guitar solo to A for the final verses and he does it by playing the solo in C and then just throwing in two bars of E to land on A for the final verses.

[stanron]

Back in the big band days key changes were everywhere. The band would play the main tune in Bb or Eb because they were easy keys for brass players to read. The singer would sing in a different key so there would be a transposition there and when the singer finished there would be a transposition back to a brass friendly key. These key changes could be quite complex and give a good intro to the singer. I've not actually checked but I imagine that most of these ended on the V chord of the new key. V to I is not called the 'perfect cadence' for nothing.

[syrynx]

Originally Posted by Zandit75

I'm certainly no expert, but I've never come across a song that jumps so far up the chart(From A to E).

Perhaps surprisingly, this modulation is subtle enough that it's easy to miss it entirely, because it requires adding only one chord to the basic I, IV, and V. That chord is the II chord of the original key, which is also the V of the new key. Since the II is widely used in songs which don't modulate, one might not realize that a key change has occurred. Some examples: Bob Wills' original "San Antonio Rose..."



...Willie Nelson's "Mr. Record Man..."



...and Willie's "One Day At A Time."

[JackH]

Originally Posted by JerrysGuitarBar

My Sweet Lord moves from the key of D to the key of E by inserting, as you say, a B7 chord (dominant of E). He does it in a beautifully smooth progression D - D7 - B7 - E.

It's obvious after being TOLD this song is in D then changes to E. Thanks for that. I'm not sure why now I thought it started in A. Oh well, lots to learn.

[JonPR]

Originally Posted by JackH

I've been trying to learn a little more theory recently and I think I remember reading about the chord used to change a key up a half or whole step falling under a "theory rule" to remember. Something like the chord needs to be in both keys or something like that. What I think I read may be more of a guideline than a rule.

The key change up a half-step is known (sarcastically) as the "truck driver's gear change" - because it's a crude way of injecting energy into a song just as it's starting to get boring. (Instead of writing another section, you just repeat the sequence a half-step up.)

Still, there is no rule saying you shouldn't do it, because it can be effective when done sensitively. A good one is Otis Redding's I Been Loving You too Long, which goes from A major to Bb major via an F chord - and then wrongfoots you by going from Bb to Gb, making you think they're doing it again (heading for B major), but it just goes back to Bb.
The most brazen example is Bobby Darin's "Mack the Knife", which does it 5 times in the space of less than 3 minutes; gets away with it through sheer chutzpah.)

The theory rule you're thinking about is called "common-chord modulation", aka "pivot chord" - using a chord shared by both keys. (There are many other methods of changing key). Pivot chords can be used to change to a few different keys.
"My Girl" is a great example of the whole step up. It starts in C, and in the instrumental break you get a Dm7-G7 (ii-V in C), then Em7-A7 (ii-V in D). It's smooth because Em is the pivot chord: you hear it as iii in C to begin with, and it's only the A7 that wakes you up to what's happening. But then (somewhere in your subconscious) you recognise that the pair of chords is echoing the previous pair, and the Em is not quite what you thought. And by then it's into D major for the last verse. It's kind of like a clever conjuring trick.

Another example would be to use Am7 to move to D7 to take you into G major. (Am7 being vi in C and ii in G.)

wiki outlines other methods:
https://en.wikipedia.org/wiki/Modulation_(music)

[JonPR]

Originally Posted by Zandit75

I'm certainly no expert, but I've never come across a song that jumps so far up the chart(From A to E).

Or down of course. E is closer if you go down.

Originally Posted by Zandit75

Coming from a Country singing background, most songs that I have sung with a key change is normally from neighboring keys mostly G to A. I sing one song that is in A for the verse, but jumps down to G for the chorus each time. It's weird, but it works for that song.

'Penny Lane' does that: key of B major for the verse, A major for the chorus - but then B major for the last chorus (clever - so you get a key change which isn't really a key change. But it still is.... )

[drtedtan]

Originally Posted by stanron

There is not one single rule for all key changes but somehow or other it works if you can get to chord V of the new key at the end of a four bar cycle. How you get to that chord will change with different combinations of keys. Experiment.

Using the V chord of the new key to modulate into the new key is called a secondary dominant and is a pretty common means of modulating to a new key.

Originally Posted by syrynx

Perhaps surprisingly, this modulation is subtle enough that it's easy to miss it entirely, because it requires adding only one chord to the basic I, IV, and V. That chord is the II chord of the original key, which is also the V of the new key. Since the II is widely used in songs which don't modulate, one might not realize that a key change has occurred.

I agree that this can be a pretty subtle modulation.

For discussion purposes, it's best to think of this as the V of the new key (aka, a secondary dominant) since it won't always be the II of the original key - that depends upon the key in which you start and the key to which you modulate. Plus, the II of a major key is minor (minor seventh if using seventh chords) and the V of a major key is major (dominant seventh if using seventh chords), so they won't be the same type of chord even if the roots happen to line up as II of the original key and V of the new key.

[syrynx]

Originally Posted by drtedtan

For discussion purposes, it's best to think of this as the V of the new key (aka, a secondary dominant) since it won't always be the II of the original key - that depends upon the key in which you start and the key to which you modulate.

It's always the II of the original key in the particular case we're discussing.

Originally Posted by drtedtan

Plus, the II of a major key is minor (minor seventh if using seventh chords) and the V of a major key is major (dominant seventh if using seventh chords), so they won't be the same type of chord even if the roots happen to line up as II of the original key and V of the new key.

The ii of a major key is minor (minor seventh if using seventh chords); the II is major. While the chords built on the second and third degrees of the diatonic scale are most frequently minor, exceptions abound, notably among a host of "circle of fifth" songs. Consider "Five Foot Two" (I III7 VI7 II7 V7 I).

[JonPR]

Originally Posted by syrynx

While the chords built on the second and third degrees of the diatonic scale are most frequently minor, exceptions abound, notably among a host of "circle of fifth" songs. Consider "Five Foot Two" (I III7 VI7 II7 V7 I).

That's because it's a secondary dominant: not II, but V/V.
Likewise "III" is really V/vi, and "VI" is really V/ii.

[JonPR]

Originally Posted by drtedtan

Using the V chord of the new key to modulate into the new key is called a secondary dominant and is a pretty common means of modulating to a new key.

Not quite. A "secondary dominant" doesn't (usually or necessarily) change the key - that's why it's called "secondary". Secondary dominants tonicise chords within the key (as in "Five Foot Two", above).
It becomes a grey area, however, if the targeted chord becomes a phrase in that key. I.e., it depends on whether it sounds like the key has changed, or if we've just been led to a non-tonic chord in a more positive way.