Update 3

I have started to break down this broad question to specific, smaller questions.

1) Classical music example for seamless transition from one section to other with changing keys

Say, I have a song revolving around a theme in E minor. Can I somehow convincingly build it up to change to a theme in, for example, A minor?

An example: you want to express the feeling when someone is buried in deep, moody thoughts for a while, then recollects herself/himself, and finds a solution. So the first part is in a slow, moody theme in E minor, and you want to fluidly arrive in an uptempo A minor theme and then end the song in that theme.

The question is not as easy as it seems (at least for me). One jazzist friend said, that "It's simple! Just throw in a II-V-I chord progression in the new key!".

Unfortunately it does not work when it does not fit the logic and patterns of the song, as we unconsciously understand those larger patterns. So in a jazz song, where chords are flying in at high speed, this solution can work, but when you have a repeated (though varied) theme, you just can't throw in some chords from nowhere.

When I tried to create such transition, I succeeded in that the change felt OK, but you had a feeling that the song would revert to its original key => it was not a convincing change.

Probably these can participate in the answer, but I'm not sure:

  • Should I go "up" to new key (i.e. bass of the first theme is E3 and I move it up to A4) or "down" (bass from E3 to A2)? Which one feels more like an "arriving" to the new theme?
  • Should I "end" the first theme and "start" the new one, or try to make a seamless transition from one theme to other (like writing a transition section with parts and bits from both sections)?

If you answer, please provide convincing examples from real world songs. Thanks!


For me, the chords/scales part is only about 10% of the problem. Let's narrow the question to more rigid styles, with clear, well-defined sections (exclude jazz, because it's too playful in this manner): say pop, or pre-modern classical era, even rock, even cosmic black metal! Or just one singer, without any instruments.

Say, you play one theme for a minute.

  • How long should be the transition between the two clear themes? (Exclude the obvious sudden version). It must be proportional to how many bars was the first theme. Or not?
  • What's your strategy if the rhythm of the dominant melodies of the two sections differ?

Update 2

Narrowing down again, I'm interested in a bunch of ideas for a "seamless" transition, like "X did that in this composition [link], and he is seamlessly changing from A section to B, and that's what X did for that.".

Also an idea for anyone else, struggling with this issue:

  • Try to temporarily transpose section B to the key of section A. If you can't make a logical, convincing transition without changing key, I don't believe it is possible with it.
  • The most effective approach will likely be based on which genre you are writing within. A Jazz modulation certainly occurs in a different way than a Classical one, though they may be similar. A lot of Rock music is Modal in nature and modulating within a Modal texture will have different methods than Tonal music. If you can let us know a genre and/or if it is Modal or Tonal, you will probably get an answer that better suits your needs. Commented Jan 15, 2014 at 21:25
  • Isn't the question "How do I go from a scale to another one without sounding that I play random chords? "? Commented Jan 15, 2014 at 21:38
  • The question is about "How can I define a new section in my song in a different key that sounds like a logical transition, from A to B".
    – atoth
    Commented Jan 15, 2014 at 23:02
  • 1
    What you're asking might be way too broad. I don't think there's any 'rule' that determines how many bars should be between the two themes. I could wait 2 bars,you could wait 4 bars, some other guy could wait 10 bars etc.It depends on the composer. Also, the 'strategy' part, would also depend on the composer. For instance, I would gradually build up to the different rhythm Commented Jan 16, 2014 at 0:23
  • Also, note that a theme can belong to two different scales. Commented Jan 16, 2014 at 8:39

8 Answers 8


What you seek is called Modulation.

The II-V-I your jazz friend told you about is pretty easy. It's really common in jazz. First you need to establish that you are in E minor, so you'll need to play something like II - V - I in E minor and then II - V - I in A minor. That's that. As you can see here for the song Nostalgia in Times Square by Charles Mingus. On bars 9,10,11 he changes keys just by playing the II - V - I of the new key (on the first two II- V -I he is omitting the I).

But if you want to make it sound better you could try two ways:

1) Find a common chord. The chords of E minor are:

IV:Amin V:Bmin
VI:Cmaj VII:Dmaj

The chords of A minor are:

I:Amin II:Bdim
IV:Dmin V:Emin VI:Fmaj VIIGmaj

As you can see, the IV of E minor is a A minor, which the I of A minor.

So what you could do is:

Eminor:I- IV-V - I (so that you establish that you are in E minor) and then I - IV (here, as I said, the IV,which is A minor, can be used as the I of theA minor scale).

-- The italic progressions are on the A minor scale

So we have I - IV - V - I - IV (I) IV V I

And the chords would be: Em, Am, Bm, Em, Am, Dm, Em, Am.

And you could do the same to go back to Eminor scale or whichever other scale has a common chord with the scale you currently play.

2) You could change the scales chromatically. Which means you play a chord and then you change some notes chromatically and it becomes a different chord. For instance:

The VII of E minor scale is Dmaj and the IV of A minor scale is Dmin. So you could play:

I - IV- V -I - IV - VII and then on the VII lower the third (F#) chromatically and you get F natural. And the chord would be Dminor, which is the IV of A minor. So you'll have:

I - IV- V -I - IV - VII - IV - V - I

The second one might not sound really good at you at first. The chords I chose might not be the best example, but both of the above methods I mentioned are acceptable

Τhere is also another way where you find harmonic chords. Like when you play G# major you could say it's Ab major and then continue to play like you are on Ab major. But I'm not 100% how to explain that, I'll just confuse you further.

should I go "up" to new key (i.e. bass of the first theme is E3 and I move it up to A4) or "down" (bass from E3 to A2)? Which one feels more like an "arriving" to the new theme?

Τhat would depend on the player (in my opinion). I would say that if the melody becomes more intense, you should go up and if the melody slows down and becomes more dramatic, you should go down -- but that is just my opinion. Some other musician could say the exact opposite and it would be acceptable.

  • I'll update the question, as this is really the smallest and easiest part of it.
    – atoth
    Commented Jan 15, 2014 at 21:18
  • I updated my answer a bit. I'm not sure what you mean with 'should I "end" the first theme and "start" the new one, or try to make a seamless transition from one theme to other (like writing a transition section with parts and bits from both sections)?' Commented Jan 15, 2014 at 21:23
  • I like to think of it rather simply, although it is not, as a process of assembling chords in a sequence where the total deviation between dominant tones in two subsequent chords is kept to a minimum, allowing the final chord to end up in a completely different tonality from the original. There are a lot of ways to arrange the sequence but if you have a melody in mind, you can use that as a secondary constraint which will leave you with surprisingly little choice of what chords to use. Commented Nov 6, 2014 at 18:16

For an example of what I think you're looking for ,check out 'Unforgettable' (sung by Nat King Cole) which is in G maj. Starts on G, but ends in C maj. Somewhere in the middle there is a key change/ modulation, but for the life of me, I haven't found where, yet. But it goes round like that quite happily.

Your whole question will need to be split to make the answers easier to come by.

  • I think the modulation is pinned down at "it's incredible", by the (often ignored by sloppy performers) E natural in the melody. I enjoy the moments in this song, but find the modulation a structural weakness. The sheet music is generally in G, but Nat performed "Unforgettable" in F.
    – Laurence
    Commented Jul 30, 2016 at 20:57
  • (Notating in F as Nat sang it in F, as Laurence said) Sounds to me as if the modulation is effected by the use of the pitch E♭ to slip into the key of B♭, and E to slip back to F. Thus the song is already in B♭ at "Like a song", and back in F at "someone been more". Then, similarly, in B♭ again at "That's why". It might be clearer with "it's incredible"'s E♭m7 that the song isn't coming back to F, but its fate was sealed with the previous chord, "That's why"'s Cm7, of which the E♭m7 is just a chromatic alteration, G becoming G♭.
    – Rosie F
    Commented Oct 11, 2018 at 13:35

To address the term "convincingly," Schoenberg describes the idea of "neutralization." The idea is to emphasize the note (or notes) that differ between the old and the new key. It's not just playing those notes; it's establishing them as "diatonic" (or at least I'd call it that if people were sure what I mean.) For example, in moving from C major to G major, one needs to display the note F while in C and then exhibit the note F# after the transposition. Playing D7-G isn't enough; that could be heard as V7V in C rather than V7/I of I in G. Schoenberg suggests that one may need to play A7-D7-G to establish a V7/V-V-I sound. Playing Am-D7-G (ii-V7-I) isn't sufficient as this could easily be vi-V7/V-V-I. A half cadence doesn't really sound like a modulation.

Up a fifth is a particularly difficult transposition to make sound convincing. I did read somewhere a suggestion that this is the reason that French Overtures and later Sonata Forms often use this pattern (along with i-III).


I've been experimenting with long transitions for key modulations. First, I'll see which notes are common between the key I'm modulation from and the key I'm modulating to. Then I'll just do something using ONLY those common keys for a few bars. If I've only got four notes to work with, that will present a good opportunity for creativity, especially if you want to use a chord in that part, which may end up being a suspended chord or a tritone or anything. After piddling with those few notes for a while, I'll introduce maybe just one note from the key I'm modulating to—a note that had not been heard in the old key. Then I'll do something else for a few more bars. Then I'll introduce another note or two until I'm fully settled in the new key. Those long transitions are probably imperceptible to most listeners, though people with perfect pitch might sense it easily. Yet the result can be quite beautiful. It might lead a listener to think, "Wow, how did that happen? That was amazing!" I've had that experience when listening to music, yet it was so well-executed that I didn't realize it was a key change until I started trying to compose my own music years later and kind of discovered the effect through my own experimentation and I gave myself the chilly fuzzies. What a surprise it was! I love key modulations!

  • I'm surprised to see people can only think of chords (maybe most people knowing music theory are jazzists), while in reality, as per my flute example, you might need to figure out how to do it with one note at a time. Your idea, though, can work without chords.
    – atoth
    Commented Nov 27, 2017 at 15:12

This is modulation, other people have already answered but I feel like I can be more succinct.

  1. Find a common chord (primary if possible I, IV, V) between the two keys.
  2. Play a few bars using just common chords.
  3. Prepare for a perfect cadence in the new key (V-I).
  4. Continue playing in the new key.

Eg: modulating from C to F.

  1. Common chords I would use are mostly C and F chords as these are the tonic, subdominant and dominant chords in each key.
  2. You could use a couple of Dm chords as this is the vi in F (perhaps the most common minor chord) and is common.
  3. Move to a C chord and cadence onto an F chord, afterwards play over a B flat chord to establish the new key signature.

The smoothest way to modulate in classical music is to use the dominant chord of the new key: if you modulate from C to G, you must add one # (that would be F#) and you get D7.

You can also change the scale chromatically as explained in another post.

"A Sentimental Mood" by Duke Ellington is a good example:

The tune starts in D minor and modulates into F Major (its relative major scale):

I:Dm for two bars

IV: Gm for most of two bars and then

V: A7 at the end of the fourth bar

The modulation now around a common chord:

I(key of D minor) or VI (key of F): Dm for one bar then

I7 or VI7 : D7 for one bar

Now D7 is VI7 but it is also the dominant chord of Gm, so we have a V of II since Gm is the II chord in the II-V-I in F major

the tune moves to the new key:

II: Gm V: C7 I: F MAJ on the last two bars

The idea is to change the quality of the I/VI common chord to make it a dominant of the II chord in the new tonality where the II chord is used as a temporary tonic.

  • I like this answer, but in the case of a Sentimental Mood I think it makes sense to do Roman Numeral analysis with a single tonal center on the entire A section. The modulation occurs at the bridge When it moves to DbMaj.
    – jdjazz
    Commented Nov 28, 2017 at 3:02
  • I see what you mean. It was just a simple straightforward example but it can be used in different contexts. I'll try to find a less obvious one...
    – user45784
    Commented Nov 28, 2017 at 7:02
  • Here is another example I've found: Reincarnation of a Lovebird. Between part C and D, Mingus has the number move from FMAJ to AbMAJ (quite a remote key: + 3b). He substitutes BbMAJ7 which isn't even played by Bb7#11 (borrowed from melodic minor) and then changes the quality to m7 (the third of Bb7#11 is lowered and the sharp fourth is raised) so Bb7#11 is a kind of "altered" (I don't mean an X7alt. chord by that here) chord leading to Bbm7. Then of course Eb7 and finally Ab MAJ7. I played it on the guitar and the short lapse into F mel is just so nicely dissonant (it is even played twice).
    – user45784
    Commented Nov 30, 2017 at 21:12

Your particular example - E minor to A minor - has an easy and obvious solution. Modify the Em chord to Emajor. Minor-to-major, there's your optimistic awakening! Then E7, your gateway into A minor. (Or even A major).

it's not just the chords of course. What's the melody going to do?

Also, if the aim is to illustrate a change of mood, do you want to feature the contrast or try to smooth over the transition?


I think I have found my answer here in this video:

Starting from 3:12 in Example 8 Alan Belkin describes how to gradually move to the new key without being obvious by changing one accidental and keeping the other notes and creating a "glue" that holds the modulation together. Other technique is to use "neutral notes" between the two keys, which deemphasizes the first key to make it easier for the second to arrive.

If anyone interested to go deeper in Example 9 which details a harder modulation from Bb Lydian to C Locrian.

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