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Thread: "IV7" question

  1. #1
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    "IV7" question

    If I see "IV7" I assume this means a dominant 7th chord...for example you might often see a blues progression described as I7/IV7/V7 to indicate all the chords are dominant 7ths.

    I've come across a usage of "IV7" to describe a Major 7th chord (which is of course the diatonic seventh-type chord built off the 4th degree of the scale). Is this notation common, correct, and/or typically used in other contexts I might not be very familiar with (e.g. classical music)?

  2. #2
    Registered User JonR's Avatar
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    Quote Originally Posted by walternewton View Post
    If I see "IV7" I assume this means a dominant 7th chord...for example you might often see a blues progression described as I7/IV7/V7 to indicate all the chords are dominant 7ths.
    That's what I would assume too - IF reading a pop, rock or jazz chart...
    Quote Originally Posted by walternewton View Post
    I've come across a usage of "IV7" to describe a Major 7th chord (which is of course the diatonic seventh-type chord built off the 4th degree of the scale). Is this notation common, correct, and/or typically used in other contexts I might not be very familiar with (e.g. classical music)?
    I'd say yes. The assumption in a classical (non-blues) context would be that adding a "7" to any chord indicates a diatonic 7th.
    So "I7" and "IV7" in a major key would both indicate major 7th extensions. (All other chords in the key have minor 7ths, so align with common jazz/rock practice of showing a b7 as plain "7").

    Where a minor 7th extension is used on a major chord (making a dominant 7th-type chord), that chord - outside of blues - will almost certainly have a dominant function: meaning it's the V of something. If not the V of the key, then it will be a secondary dominant (V of some other chord in the key), or maybe the primary dominant of a new key.

    So if, for example, you had a C7 chord in key of C major, that would not be labelled "I7" (because that would indicate Cmaj7), but "V7/IV" - IOW, the dominant 7th of the IV chord (F), ie, C7.
    An F7 would never occur in the key of C major, because it is not a secondary dominant of any other diatonic chord. It would be the dominant (V) of Bb or Bbm, so if it does occur, it would signal a modulation of some kind.
    The other context might be "modal interchange" - eg, F7 is the natural IV chord of C dorian, so in the context of C dorian mode the label "IV7" would stand for F7. "I7" would, in that case, be Cm7 (and possibly labelled "i7").

    In short, you need to assess the context before drawing conclusions about what chord symbols might mean.

    BTW, the above is largely guesswork, so any corrections from CPP experts are appreciated!

  3. #3
    JazzNerd gersdal's Avatar
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    Quote Originally Posted by JonR View Post
    So if, for example, you had a C7 chord in key of C major, that would not be labelled "I7" (because that would indicate Cmaj7), but "V7/IV" - IOW, the dominant 7th of the IV chord (F), ie, C7.
    An F7 would never occur in the key of C major, because it is not a secondary dominant of any other diatonic chord. It would be the dominant (V) of Bb or Bbm, so if it does occur, it would signal a modulation of some kind.
    The other context might be "modal interchange" - eg, F7 is the natural IV chord of C dorian, so in the context of C dorian mode the label "IV7" would stand for F7. "I7" would, in that case, be Cm7 (and possibly labelled "i7").
    How would a blues progression be in a harmonic analysis then? Something like this

    Code:
    | C7| F7 | C7 | C7 | F7 | F7 | C7 | C7 | G7 | F7 | C7 | G7 |  
    
    | V7/VI | ?7 | V7/V | V7/IV | ?7 | ?7 | V7/VI | V7/IV | V7 | ?7 | V7/VI | V7 |

  4. #4
    Registered User JonR's Avatar
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    Quote Originally Posted by gersdal View Post
    How would a blues progression be in a harmonic analysis then? Something like this

    Code:
    | C7| F7 | C7 | C7 | F7 | F7 | C7 | C7 | G7 | F7 | C7 | G7 |  
    
    | V7/VI | ?7 | V7/V | V7/IV | ?7 | ?7 | V7/VI | V7/IV | V7 | ?7 | V7/VI | V7 |
    The problem is that I7 and IV7 chords in blues are non-functional. So functional analysis is redundant.

    Of course, within rock/jazz, it's quite acceptable to denote dom7 chords according to scale step (with "7"). So "I7" and "IV7" are OK - everyone understands what they mean, and that they are not maj7s, which would be written as "Imaj7" and "IVmaj7"
    IOW, writing the I and IV chords in a blues as "I7" and "IV7" implies no functional connotation. Not does it have anything to do with diatonic extensions (because the idea of what is "diatonic" to a blues is variable anyway). The symbols are jusr recording the fact that the chords have b7s.

    You could argue that the C7 immediately before each F7 is "V/IV", but the C7 doesn't otherwise have that function. It doesn't have a b7 (Bb) in order to resolve to F; it has it because it represents the normal 7th of C blues scale (n that sense I guess it is a diatonic extension). Likewise, the F chord has an Eb not for any functional reason (implying a cadence to Bb), but because it represents the minor end of the spectrum of the blue 3rd in C major (whose major end is in the tonic chord of course).

    But the question was really about the reverse issue: the context in which it's normal to write diatonic 7th chords on I and IV in a major key as "I7" and "IV7".

    IOW, we simply apply different rules about chord symbols according to the kind of music we're looking at, and the accepted practices within that music.

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    Thanks Jon.

    This came up while I was reading this article analyzing a Beatles song (about as mainstream a pop/rock context as you can get!), but by an author with a classical theory background.

    Looking at it again I note that not only does he notate the FMaj7 chord (and it's definitely a Maj7 chord he's talking about) as IV7 - fair enough if that notation is commonly used to indicate a diatonic chord in the classical world - but he also specifically notates the chord as "F7" rather than something like FMaj7, so you can see the source of my confusion...do you know if this is also typical??

  6. #6
    Registered User Malcolm's Avatar
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    I'll jump in ...... we have several kinds of seventh chords.... they may, or may not be used correctly.
    C7 known as the dominant seventh R-3-5-b7
    Cmaj7 known as the major seventh R-3-5-7
    Cm7 known as the C minor seventh R-b3-5-b7
    Cdim known as the C diminished R-b3-b5 and then with b7 or bb7.

    That dominant seventh (C7) finds it's way into country, rock, blues and pop, however, not necessarily always as the dominant seventh chord, i.e. it's used incorrectly some of the time.

    The A7 and B7 are easier to make than the A or B (major) chord so you see them substituted quite a lot, especially in fake chord sheet music.

    Printed sheet music may or may not be theoretically correct. If you are playing covers sometime it's best to just play what is written and not question it. Think of rules as being guidelines, the only true rule - if it sounds good it's good.
    Last edited by Malcolm; 04-04-2010 at 03:56 AM.

  7. #7
    Registered User JonR's Avatar
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    Quote Originally Posted by walternewton View Post
    Thanks Jon.

    This came up while I was reading this article analyzing a Beatles song (about as mainstream a pop/rock context as you can get!), but by an author with a classical theory background.

    Looking at it again I note that not only does he notate the FMaj7 chord (and it's definitely a Maj7 chord he's talking about) as IV7 - fair enough if that notation is commonly used to indicate a diatonic chord in the classical world - but he also specifically notates the chord as "F7" rather than something like FMaj7, so you can see the source of my confusion...do you know if this is also typical??
    I know that site well - it's great - but (slightly surprisingly) I've not noticed how he notates maj7 chords before.
    I don't know how typical it is either, but I would guess anyone with his background would do it the same way. (Like the way he uses lower case for minor chords: "a" = Am, etc., which I've not seen elsewhere)
    I wonder how he would have written that "F7" if it had been a dom7-type chord?

  8. #8
    JazzNerd gersdal's Avatar
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    Quote Originally Posted by walternewton View Post
    This came up while I was reading this article analyzing a Beatles song (about as mainstream a pop/rock context as you can get!), but by an author with a classical theory background.
    Interesting. Thanks for the link. He even analyse a blues like progression: http://www.icce.rug.nl/~soundscapes/...WP/ishst.shtml

    No 7th's just I, IV and V...

  9. #9
    Registered User JonR's Avatar
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    Quote Originally Posted by gersdal View Post
    Interesting. Thanks for the link. He even analyse a blues like progression: http://www.icce.rug.nl/~soundscapes/...WP/ishst.shtml

    No 7th's just I, IV and V...
    I guess he's just interested in chord function, and not in (to him) superfluous blues extensions.
    (He highlights the maj7 walter pointed out because of its relevance to the harmonies.)

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    that's retarded. they should have made it more consistent.

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    Quote Originally Posted by JonR View Post
    I wonder how he would have written that "F7" if it had been a dom7-type chord?
    Me too...FWIW if you look at his article on "Birthday" he notates the dom7 chords in the (12 bar bluesy) verse as A7, D7, E7, so there's at least some inconsistency in his use of "x7" (or perhaps just a typo in the "No Reply" article...)?

  12. #12
    Registered User JonR's Avatar
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    Quote Originally Posted by walternewton View Post
    Me too...FWIW if you look at his article on "Birthday" he notates the dom7 chords in the (12 bar bluesy) verse as A7, D7, E7, so there's at least some inconsistency in his use of "x7" (or perhaps just a typo in the "No Reply" article...)?
    Possibly. I've been trying to think of other Beatles songs with maj7s in, to see what he does there.
    The only one I could think of was Michelle, but he makes no reference to the maj7 extension on the chord in question (Db in 3rd bar of intro, and 9th bar of bridge).

    EDIT: likewise for the title phrase in Strawberry Fields Forever: maj7 in vocal over the IV chord, not mentioned.
    Last edited by JonR; 04-04-2010 at 04:10 PM.

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    Quote Originally Posted by JonR View Post
    Possibly. I've been trying to think of other Beatles songs with maj7s in, to see what he does there.
    The only one I've come up with is "Something", in which he basically spells it out as CMaj7 at the end of the opening vocal phrase and then uses C7 for the dom7 which follows it up.

  14. #14
    Registered User JonR's Avatar
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    Quote Originally Posted by walternewton View Post
    The only one I've come up with is "Something", in which he basically spells it out as CMaj7 at the end of the opening vocal phrase and then uses C7 for the dom7 which follows it up.
    Right - in which case he seems to be inconsistent in his labelling!
    I notice he describes the C7 in this case as "V-of-IV", while the "F7" (Fmaj7) in No Reply is just "IV" - perhaps in his system the difference in function is enough to distinguish "7" meaning a dom7 and "7" meaning a maj7 (if it's I or IV)...

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    Quote Originally Posted by JonR View Post
    Right - in which case he seems to be inconsistent in his labelling!
    I notice he describes the C7 in this case as "V-of-IV", while the "F7" (Fmaj7) in No Reply is just "IV" - perhaps in his system the difference in function is enough to distinguish "7" meaning a dom7 and "7" meaning a maj7 (if it's I or IV)...
    Hmmm...well I'm curious now so I've been searching through my Beatles scores book for more examples of Maj7 chords to see how he handles them, here's one:

    The CMaj7 played on the organ that opens "Only a Northern Song" is a bIII in the key of A major, (so a non-diatonic, non-functional chord, no?) - he notates it as "C7".

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