Song key, chord progressions, key changes...

[Naenyn]

I've got a pretty basic question for you theorists... that I will ask by way of example.

Lets say you've got a song written in C major.. and you go with a I-IV-V-I chord progression.. Nice and basic. Now lets narrow the view down from the entire song to just the IV portion of the chord progression. Can that portion of the song be considered to be in the key of F? If you were to remove that portion of the song and view it on its own ... it would be the key of F, wouldn't it? I mean.. when you're playing the F portion of the chord progression, to remain in key, you have access to all of the notes in the F major scale, right? Not just the ones that are also in C?

I've always been confused by this .. because when someone says a song is written in a particular key, the song can still appear to change keys as the chord progression changes, right?

[Doug1978]

You'll probably get some more in depth answers, but in a nutshell: that IV in the key of C contains the F-A-C notes.

The F A and C notes belong to a few different keys: C, F and Bb.

Hypothetically, if your song was entirely based (extremely boringly!!) on just these three notes, then your song could be in any of those keys.

Practically speaking, your song will (surely) use up more notes than just F A and C.
Those other notes that are used in your song will give the indication of what key your song is in.

For example, a simple and boring track based around just F A C Bb and Eb will be in the key of Bb.



ps, you may well get some other people here scolding you, as technically the ''C Major scale'' is different from ''the key of C''.


''the song can still appear to change keys as the chord progression changes'' - indeed, and this can be a short-lived (or hinted) modulation, or a more substantial one.
It depends on what new notes are used and to what frequency / degree: are they merely a momentary extra/outside coloring before the track returns to the notes of the previous key, or do these notes now form a substantial new pattern with the majority of notes outside of the previous key?

pps, check out a few articles on modulation and key changes to understand further.

Cheers.

[stevewisnoski]

I would say, unless the song had modulated, it is still in the key of "C". The F chord is functioning in the key of C as a IV chord. Now, when you turned around back to the top of the section, and played C7, then F, you would have modulated into the key of F the most common way, via a V7-I modulation. The C7, would become the V chord of the new key, F. The progression would then be F- Bb-C7.

[jancivil]

I've got a pretty basic question for you theorists... that I will ask by way of example.

Lets say you've got a song written in C major.. and you go with a I-IV-V-I chord progression.. Nice and basic. Now lets narrow the view down from the entire song to just the IV portion of the chord progression. Can that portion of the song be considered to be in the key of F? If you were to remove that portion of the song and view it on its own ... it would be the key of F, wouldn't it?

The I IV VI I indicates key. F is IV? It isn't I. It becomes the key of F through some device, typically we'd call it modulating to the key of F. This isn't happening in a I IV VI I in key of C.

I mean.. when you're playing the F portion of the chord progression, to remain in key, you have access to all of the notes in the F major scale, right? Not just the ones that are also in C?

There is no indication here of key of F. There is no requirement through "theory" that the Bb note be considered, ie., purely in order to suit F. What's the musical idea? Are you going to want an F# to suit that G, equally? You have a musical idea to do that or you don't. Actually I suggest to deal with musical examples rather than 'theorizing' by 'theorists'. 'Narrowing the view down' to the F chord has no actual use to you, out of nowhere.

There is no musical example; so even as C7 to F as though a V-I has been indicated, that is not necessarily a modulation. We can call that a V7 of IV just as readily.

[Naenyn]

Thank you all for the responses! People are welcome to scold me just as long as they also correct me.

I guess what I was wondering is ... when playing the F portion of the chord progression I mentioned, the notes that you'd have to work with and still sound like you're in-key would be from the F major scale, right? So that Bb would sound ok when played with that that F, but it isn't a part of the key of C..?

[stevewisnoski]

Hi naenyn, over the IV chord, which in a major harmonized scale, the IV would be major, in this case, you would be playing C major, over F major, which would be playing Lydian. Which is a valid choice over a major chord. I think you are thinking that you need to play the major scale of each chord in the progression. By playing C major, over F major, the 4 of the scale is sharped (the F chord), and indeed is a valid choice in improvisation. If you played c major over the V chord (G7), the result would be playing mixolydian, flatting the 7th, a perfect choice over a dominant harmony used again and again. There is so much information online that talks of using modes, in particular, using major scales at different pitch levels against a harmony at any given time. Find some of those. Long ago, if I saw C maj, I would think you play a C major scale. Later in life, I learned that playing G major was a better choice, which would yield lydian, a sharped 4, as I noted above. There would be endless choices to play over a functioning harmony, but playing Lydian or mixolydian would be 2 good choices. You can find that info real fast with a couple of keywords.

[jancivil]

when playing the F portion of the chord progression I mentioned, the notes that you'd have to work with and still sound like you're in-key would be from the F major scale, right? So that Bb would sound ok when played with that that F, but it isn't a part of the key of C..?

"the F portion of the C major chord progression" is the salient part here. The notes of C major are not the F major scale, so as far as it goes, the answer is no.
Whether or not 'Bb would sound ok' is another question and there is no music to talk about here, so there is no real answer.

[jancivil]

you would be playing C major, over F major, which would be playing Lydian..

No, playing C major and playing F lydian are two different things. If that is right, 'playing F major scale in C major' is equally right. It's not, because we have the one tonic, C. Which has been denoted by the statement 'In C major'.

Additionally, if 'F lydian' is right, we have up to seven different things to call to bear anytime we have a chord other than C.
Chords <in C major> are called "in C major" because the tonic is C. If the tonic is C, the only 'lydian' possible is C lydian. A mode must have its own 'tonic' or center. F lydian's is F. If we follow your reasoning, what you're proposing is seven names for the one thing, really. All this provides is confusion. There is no reason for calling C major this other thing. C major as a scale over an F chord in C major has not undergone a change of identity just through the chord change. "in C major, C major scale over an F major chord is a C major scale" is sufficient; and true, period.

[jancivil]

There would be endless choices to play over a functioning harmony, but playing Lydian or mixolydian would be 2 good choices. You can find that info real fast with a couple of keywords.

"functioning harmony" and <modes> do not agree.
if you have harmonies that function for instance in C major, the whole character and the whole idea and point of lydian mode will be obviated in favor of how the notes work to function towards C as I.

There is no F lydian in C major. F lydian: the B is the characteristic note (particularly per the expectation of major). The B functions, in addition to that F, as a tension which the expectation of C major - the reality of C major - wants a resolution for. In F lydian, that is not the case.
The whole idea of F lydian is to have the character of lydian; F being the basis, B has a relationship with it that is different than its relationship with C. F and B is a strong tension in the functional dominant 7th harmony, with the strong expectation 'resolve to E C'.

You're in C major/you're in C major. B in F lydian is free to 'resolve' to A, a typical move owing to the fact of the F 'tonic'.
If we encounter a Dm in C major and 'decide' to 'play in D dorian', the same applies. The character note is again B; B to C in D dorian is 6 to 7. There's a whole feel to this, to any mode.
If C major is our key, the other thing applies, B as leading tone. Two_different_things.

[jancivil]

By playing C major, over F major, the 4 of the scale is sharped (the F chord), and indeed is a valid choice in improvisation. If you played c major over the V chord (G7), the result would be playing mixolydian, flatting the 7th, a perfect choice over a dominant harmony used again and again.

I know I'm hammering on it now, but this is a lot of language that describes nothing more than staying in key. In C major, B is not 'sharped', it's there by default.
The F in C major is not flatted, it's the normal F of the key. Using the notes of the key while in the key seems to be 'a perfect choice'. The mere occurrence of these chords does not through itself force any further choices or thought. This overcomplicates a very simple matter.

There would be endless choices to play over a functioning harmony, but playing Lydian or mixolydian would be 2 good choices. You can find that info real fast with a couple of keywords. There is so much information online that talks of using modes, in particular... Find some of those.

No, please don't. You'll just end up confusing things in this manner and may even end up disseminating the mistake some more again. The internet strikes again.

Long ago, if I saw C maj, I would think you play a C major scale. Later in life, I learned that playing G major was a better choice, which would yield lydian, a sharped 4, as I noted above.

As a principle, as an absolute? You seem to like lydian better than major is all. If 'C major' is the chord symbol, the 'better choice' has to do with what C major is in the musical passage. F# may even be a wrong note.

Above, you had F as flatting the F#. Now F# is raising the F. Both can't be true. The true statement about C major is [1 = C; 2 = D; 3 - E;] 4 = F...
C lydian has a true statement which is false for C major: 4 = F#. NB: it's not C lydian just through the chord C major; it's C lydian when C is the 'tonic' or center'.
In G major, C major chord is the IV chord and F# is the normal 7 in the 7 note scale.

[stevewisnoski]

Sigh...if you play a C major scale over an F major harmony, starting on whichever scale degree you wish, it would sharp the 4. A simplification of how to view modes. In this case, Lydian.

[jancivil]

If you play a C major scale in the key of C major, you are playing a C major scale in C major. There is no lydian mode in major. That is a nonsense statement. You have gathered up a bunch of information on the internet you don't quite understand and now, not only overconfidently spreading your sciolism, you're going to do "Sigh"? You don't know what you're doing. I'm the one being patient.
Wait a bit and others will weigh in on this.

You apparently believe that seven modes of seven modes = 7 names for major, to be called up for any given chord change in major. That is a mistake. If you're in major that's all you need.
I don't know what's difficult about 'in C major' part of 'The F major harmony in C major'. WHEN F IS THE I, the 'tonic' as it were, the notes F G A B C D E = F lydian. The notes F G A B C D E with C tonic = C major scale.

Read this statement again, this time think on it: Above, you had F as flatting the F#. Now F# is raising the F. Both can't be true. If it isn't clear, both can't be true at the same time. If there is the one key, C major, which we have yet to deviate from, you have two conflicting statement as true.
You're confused: which is it? Are we in C major or aren't we? IF WE ARE, F is native to the key. If we're in G, F is flatting the F#. But we aren't in G, the only thing that has happened in either case is a chord came in. We have not considered any change of key. Coming in with a factoid belonging to nomenclature of {new} key just because a chord {IN C MAJOR} comes into play is NOT simple, it's a useless complication. It's a fundamental mistake in terms!

"A simplification of how to view modes. In this case, Lydian." It may be true that your understanding of 'F lydian' stems with C major but if you believe these are the same thing, that is certainly a mistake. I would rather it not become other people's mistake.
It is the very opposite of simplifying the issue of C major. You will ultimately have seven names for one object following this reasoning. It's a confusion of the issue.
AGAIN: if your harmony is IN C MAJOR, there is no need to think of another scalar formation. It's a waste of time, it's a useless consideration, it's actually stupid.
The character of a mode isn't going to materialize in major. You really should read what you're replying to, you stand to learn something really valuable.

F lydian is the 4th mode of C ionian {rather than a mode of C major}. Equally, C ionian is the fifth mode of F lydian. C ionian (let alone C major) is not to be taken as the parent for six other modes. They have as much identity themselves. C major carries a connotation of harmony. If you start imposing 'major key harmonic paradigm' onto modes, you're probably going to obliterate the mode. One might with a certain experience know how to gauge a G7 chord in F lydian, but more typically C major likes its dominant 7th; if we've in fact established C major it *is* the dominant 7th. Chances are high that this harmony in F lydian is going to dissolve the mode into C major.
So 'playing in F lydian' is certainly a different thing with different considerations and really a different essential reason to be, than 'playing in C major'.
The F chord does not change the key nor the C tonic as per mode. F lydian is based on F as though a tonic, not F chord in whatever key we find it in: F is the 1 of its 7.

[Naenyn]

So a good portion of the responses in this thread have gone way over my head. I do appreciate you folks taking the time to try to explain things, though!

So if I wanted to play melodic notes to accompany that Fmaj chord in the progression and remain entirely in-key ... would I be playing only notes from the Fmaj scale? Or Cmaj?

[someone called simon]

So if I wanted to play melodic notes to accompany that Fmaj chord in the progression and remain entirely in-key ... would I be playing only notes from the Fmaj scale? Or Cmaj?

You would play the notes of the key of C, if your goal was remaining entirely in the key of C as you state. Note that there is only 1 note different between the keys of C and F, so in practice most of the notes will be the same. The note that differs is the B. In the Key of C it's natural, in the key of F it's flat.

In practice you'll find many instances where a song in C will include a flat B, instead of or as well as well as a natural one, and a song in F will include a natural B, instead of or as well as a flat one (amongst many other apparent departures from key).

Music usually should be written coming from what sounds appropriate to the composer, rather than following the very narrowest of rules from music theory. The rule of staying only with the notes from the key would be a very narrow rule. It's not a rule, it's just a handy thing to understand, a tool you could use when you're wanting to achieve a sonically simple result (to a western ear at least), though really your ear likely would have told you that anyway.

[jancivil]

So if I wanted to play melodic notes to accompany that Fmaj chord in the progression and remain entirely in-key ... would I be playing only notes from the Fmaj scale? Or Cmaj?

In practice you'll find many instances where a song in C will include a flat B, instead of or as well as well as a natural one, and a song in F will include a natural B, instead of or as well as a flat one (amongst many other apparent departures from key).

IE: there are musical reasons. Again, try to place theory within musical thought.
A Bb in C major is likely a little pull to the F harmony. It may be in the V7 of IV chord, C major with a minor 7th, or it could just be in the melodic line, eg., Bb to A (voice-leading of the resolution C7-F, or suggestive of something more subtle).
B to C in F major, well there's a secondary leading tone [to V] aspect.

FTR, I would have never brought in modes, that opens up a whole can of worms and the misapprehension of people that believe the internet too readily, ready to show off basically a smattering of information that isn't knowledge. Happens too often here.