# IV7 chord role?



## requiem_aeternam7 (May 14, 2010)

Can someone with a music theory PHD ( :mrgreen: ) explain what the IV7 chord does, or how is it used?

IV is generally accepted as the pre-dominant and obviously I know that IV7 can be used to modulate to the bVII of a scale. i.e. from c major to Bb major. 

But apart from strict modulatory purposes, what else (if anything) is this used for? Because I could have sworn I saw it used several times by beethoven/handel and others but not for a modulatory purpose, I just don't recall what pieces they were and what it WAS used for but I seem to remember it just going to V but if that's the case then why use IV7 and not just IV, why add that 7th and confuse the ear?

I'm sure it's widespread in jazz and such as they just add 7ths to everything but can someone explain to me this chord's usage in a more standard/classical context?


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## Dave Connor (May 14, 2010)

Well, it doesn't have to be used to modulate - it can be used as a V of IV. It creates a greater gravitational pull to that chord. It's a secondary dominant really. Any chord can be preceded by it's V in traditional harmony which the literature shows in abundance.

EDIT Oh heavens you meant a dominant IV chord which I read as the tonic made dominant. Yes that would force a type of modulation if only temporary or transient. Beethoven is not a good example since he constantly was surprising people with the {seemingly} wrong functioning chord. If you see it in Haydn or Mozart my guess would be that it would often go to the bVII as you said.


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## requiem_aeternam7 (May 14, 2010)

yes, but is there any non 2ndary dominant usage? I.E. not going to bVII, is there anything else that it's used for, that's what my question is.


http://musictheoryexamples.com/9PD7.html


you can see examples here but I think they made a mistake. the section is listed as IV7 but all the examples they show is of iv7 big difference as iv7 lacks the tritone of IV7. 

iv7 is no big problem I can understand the use of that for color but IV7 is a completely different type of sound.


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## Nick Batzdorf (May 14, 2010)

You have to know what comes next to answer the question, requiem.


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## Patrick de Caumette (May 14, 2010)

Evn though it could be considered a secondary dominant role of sorts (or rather a tritone sub role), IV7 resolves very well to III- as well (taking a lydian b7 scale) 

There's the obvious blues reference there, but not sure Beethoven was thinking of it this way 8) 

Since the b7 of IV also introduces a minor 3rd within the key, that coloring being also used then (I major / I minor), it could be a way to look at it, and the voice leading going back to I is still strong. 

Obvious move to V7 is even more referencing the blues.

It's all good


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## madbulk (May 14, 2010)

Nick's answer is pretty air tight. 
But functionally? what else are you gonna come up with? Yeah, you can voice lead to III or back to I or over to i, but if you're not moving to or at least implying VII, and you're looking for a nice function you can label from IVx7, I say you're playing the blues there, Ludwig.


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## Narval (May 14, 2010)

requiem_aeternam7 @ Fri May 14 said:


> can someone explain to me this chord's usage in a more standard/classical context?


For example? Post some classical music situations in which that chord is used, and then ask your question about its usage. The more general usage is derived from the usage in context.


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## madbulk (May 14, 2010)

Narval @ Fri May 14 said:


> requiem_aeternam7 @ Fri May 14 said:
> 
> 
> > can someone explain to me this chord's usage in a more standard/classical context?
> ...



Like NB said.


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## Dave Connor (May 14, 2010)

It could be used in a sequence if you went from IV to IV7 and then went to another major chord chord as in to III III7 and so on. You can get away with a lot in a sequence as long as the first member of it is solid.
Of course one thinks of the Blues when you have even I7 without a traditional treatment of the Dominant. But it seemed that wasn't the nature of the question. 

In this day an age anything goes anytime. Traditionally at least in the Classical era composers always explain themselves. So if Beethoven starts a piece written in E major in C Major (shocking to the listeners who were very keene on key centers in their hearing in those days) he eventually shows it as a Neapolitan VI (C) to V7 (B) in E.


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## requiem_aeternam7 (May 14, 2010)

patrick de caumette I think you hit it on the head... it makes sense now yes the IV7 can lead to iii or III, in which case if it leads to III or better yet III7 that means it becomes the augmented 6th to the home key's relative minor. i.e. if we're in C major and you play F7, it leads as an augmented 6th into E major 7 which is then the dominant of A minor so it's a cool way to modulate/progress into A minor from its relative C major. ~o)


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## Patrick de Caumette (May 14, 2010)

IV7 / III7 / VI- is certainly a very common occurance when VI- is the tonal center...


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## Narval (May 14, 2010)

requiem_aeternam7 @ Fri May 14 said:


> the IV7 can lead to iii or III, in which case if it leads to III or better yet III7 that means it becomes the augmented 6th to the home key's relative minor. i.e. if we're in C major and you play F7, it leads as an augmented 6th into E major 7 which is then the dominant of A minor so it's a cool way to modulate/progress into A minor from its relative C major. ~o)


That's a rather small leap. Modulations to far more distant tonalities are just as easy. Actually, you can shortly go from anywhere to anywhere while respecting all the classical standards. Starting from IV7, can you think of any chord you can't reach by passing through an intermediary chord? I mean, without breaking any of the scholastic rules of voice leading. In fact, one can go from any chord to any other chord by passing through only one intermediary chord. For example, from E7#5 to Bbm, through F#dim7.

Any exception you can think of?


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## requiem_aeternam7 (May 14, 2010)

Narval @ Fri May 14 said:


> requiem_aeternam7 @ Fri May 14 said:
> 
> 
> > the IV7 can lead to iii or III, in which case if it leads to III or better yet III7 that means it becomes the augmented 6th to the home key's relative minor. i.e. if we're in C major and you play F7, it leads as an augmented 6th into E major 7 which is then the dominant of A minor so it's a cool way to modulate/progress into A minor from its relative C major. ~o)
> ...



well that's certainly an interesting discussion but can you please elaborate cus I'm not following you. 

How are you getting from E7 to F#dim7? E7 to my knowledge only resolve to either A/a or Eb/eb


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## Rob (May 15, 2010)

typically it's interpreted as an augmented sixth, that's to say that the correct spelling isn't F7 (F,A,usually no 5th,Eb) but F.A,D#. There's an excellent wiki page here...

http://en.wikipedia.org/wiki/Augmented_sixth_chord


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## requiem_aeternam7 (May 15, 2010)

Rob @ Sat May 15 said:


> typically it's interpreted as an augmented sixth, that's to say that the correct spelling isn't F7 (F,A,usually no 5th,Eb) but F.A,D#. There's an excellent wiki page here...
> 
> http://en.wikipedia.org/wiki/Augmented_sixth_chord



thanks that's basically the deduction I came to as well


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## Patrick de Caumette (May 15, 2010)

Narval @ Fri May 14 said:


> requiem_aeternam7 @ Fri May 14 said:
> 
> 
> > the IV7 can lead to iii or III, in which case if it leads to III or better yet III7 that means it becomes the augmented 6th to the home key's relative minor. i.e. if we're in C major and you play F7, it leads as an augmented 6th into E major 7 which is then the dominant of A minor so it's a cool way to modulate/progress into A minor from its relative C major. ~o)


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## Narval (May 15, 2010)

requiem_aeternam7 @ Sat May 15 said:


> How are you getting from E7 to F#dim7?


In B (melodic) minor, E7 to F#dim is written in Roman numerals: IV7 to Vdim7. Respell the F# note into Gb and you have the VIIdim7(3rd inversion) of Bb (harmonic) minor, a chord that happily lands on the new tonic.

My point being: given any chord, any other chord is no more than two steps away. And that, without breaking the scholastic rules of resolving.




> E7 to my knowledge only resolve to either A/a or Eb/eb


E7 directly resolves to many other chords. If we only take the major chords, we have your A and Eb, and then we have F#, C#, C, F, Ab, and B - that makes 8 out of a total of 11 major chords to chose from - not bad, eh? Same performance with minor chords: Am, Bbm, Cm, C#m, Ebm, Fm, F#m, and G#m. There are only 7 major and minor chords, out of 23, that E7 does not directly resolve to: Bb, D, G, Bm, Dm, Em, and Gm.

E7 also resolves into less _stable_ chords like dim,., aug., and sus. chords. Plus, it resolves to dominant 7 chords. And MA7 chords. And 9 chords. And b9 chords. And the rest of them.


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