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Secondary Dominants & Modulations

Discussion in 'General Instruction [BG]' started by Howard K, Jan 17, 2003.


  1. Howard K

    Howard K

    Feb 14, 2002
    UK
    Soooo, what is a secondary dominant and what is modulation?

    :)
     
  2. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

  3. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Modulating is changing key, basically. Most chord progressions don't stay in one key entirely, they move through different key centres, though they very often come back to the original key. Generally speaking, it can make a chord sequence more interesting when it ventures into different keys and doesn't just stick doggedly to the one key.

    A secondary dominant... heh, well there are two definitions I've heard. In fact, my two music teachers at college used to have an ongoing argument as to which was correct, but here we go...

    1) A secondary dominant is the dominant of any key other than the tonic - and is used for the purpose of modulating. Very often with the 3rd in the bass. The idea being, that this dominant chord is used to move into the new key. So, for example if you're in C major. You could go C A7/C# Dm. Now, you've modulated to D minor, via an A7/C# chord. That A7/C# chord is a secondary dominant - it's not the dominant of the key we're in (C), it's the dominant of the key we're moving to (D minor). Another example is C E7 Am. E7 is the dominant 7th of A minor, so it's a secondary domininant that we're using to modulate to A minor. Now, we might not stay in A minor - in fact after than A minor chord we might move on elsewhere, but that's the nature of modulations - they're not permanent key changes. They're sorta key changes on the fly.

    2) The other definition I've heard is essentially very similar to the first - but it says that a secondary dominant is the dominant of the dominant (rather than the dominant of any other key). So, by this definition, in C major, a secondary dominant would be a D chord used to get to G major (G being the dominant of C, D being the dominant of G). This is a very common modulation. For example - in a tune in C major, you might have at some point a D7/F# chord (or, if it were me doing it, it'd be a D9/F# chord :)) then a G chord. In this case, the D7/F# chord is the secondary dominant, and it's taking us to G major, albeit probably temporarily. An example : (I don't know why this springs to mind) but, do you remember the Wombles theme? The chords are (if memory serves) C C/B Am7 Em/G F C/E D7 G - then the sequence repeats. Now, the D7 here is modulating us to G - so D7 is the secondary dominant. However we don't stay in G, we go straight back to C. So this modulation isn't really taking us far - it's just a quick excursion to the dominant to make it a little more interesting.

    The reason that the 3rd is often in the bass, is that it makes for a nice bass line. In that first example - C A7/C# Dm - the bass line would be C C# D. That's a nice lil bassline, it moves the sequence on nicely - where as if the 3rd weren't in the bass, it'd be C A D, which isn't quite as neat, if you see what I mean. Having the 3rd in the bass means that the bass only need resolve up a semitone from the secondary dominant to get to the tonic of the new key, if you see what I mean.

    Does that make sense?
     
  4. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Ed, are you saying that it's only a secondary dominiant if you don't actually move to the new key?

    Cuz you can throw ii7-V7's all over the place, without actually resolving any of them - but to me they wouldn't count as secondary dominants unless you were actually modulating - i.e. unless the V7 is resolving to a I.
     
  5. Howard K

    Howard K

    Feb 14, 2002
    UK
    Yes it does make sense!!!!

    I thought I was opening up a whole can of worms with that one... but yes that does actually mean something to me!

    So, a non-diatonic dominant chord in a progression that doesnt resolve to the tonic of a new key it is a secondary dominant... if that non-diatonic dominant chord is resolved to the tonic in the new key it is a modulation.

    Good stuff, thanks :)
     
  6. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Well that seems to be what Ed said. My understanding of it is that it is a secondary dominant if it *does* resolve to the tonic of the new key. The secondary dominant is a means of modulating to the new key.

    So, in that example Ed gave - in G major, going Cm7 F7 Bb - that is a modulation to Bb, and F7 is the secondary dominant, to me. And if it just went Cm7 F7 Dm7 G7 (or whatever - i.e. not going to Bb major0 - then F7 *isn't* a secondary dominant, because it's not modulating. That's my understanding.
     
  7. Howard K

    Howard K

    Feb 14, 2002
    UK
    Aah conflicting opinions.. now I've got my head around it at least I can undertsand iether arguement.

    FYI - I posted this q? because I read a little about it in Sher's Improvisers Bass Method, but really didnt 'get it'. I knew I'd get a better explanation here :)
    I'll go home and read it again and see what Sher says..
     
  8. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    Isn't the point that there is only one dominant chord - the V in each major key, so if you see another one then it is "secondary" ? It can imply a key change or just be a substitution, but it is still not the "primary" dominant in the key.
     
  9. Howard K

    Howard K

    Feb 14, 2002
    UK
    Actually hang on I think I have it...

    the secondary dominant is the non-diatonic domainant chord thrown into a prgression.

    ...of course, the modulation only occurs WHEN you resolve that chord to the tonic of the new key

    ...if it doesnt then you've just chucked a secondary dominant into the progression
     
  10. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Well that's thrown up an issue.

    I was taught in college that it's only a secondary dominant if you're modulating - i.e. if it resolves. That site you posted Bruce, seems to imply that?

    What do others think?
     
  11. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    I think in classical theory, you are told that accidentals imply a key change and having a chord that doesn't belong would certainly be equivalent.

    But in Jazz, there are lots of chord substitutions, that don't necessarily mean a key change.

    I think that "offcially" you have modulated, but if it was only there for a bar or half a bar then a Jazz improviser might not see it that way?
     
  12. Howard K

    Howard K

    Feb 14, 2002
    UK
    So, if you're definition is correct, how would you describe the non-diatonic dominant chord in a progression that doesnt modulate to a new key?

    Ed's definition makes more sense to me at the moment... maybe this is one of those cross the atlantic and it changes things?
     
  13. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    I was saying that a classical musician would say that the key had changed, no matter how short a time it stayed there - a Jazz musician might say it was a substitution for another chord?
     
  14. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Yes - that's true - but what about sequences of ii7-v7 chords that don't actually move to a I? You could go Dm7 G7 Em7 A7 Fm7 Bb7 Gm7 C7 Fmaj7. That sorta thing is fairly common (not as drawn out as that, perhaps :)). Now, the C7 is a secondary dominant cuz it resolves to Fmaj7 - i.e. V7 I. But what about the others - the G7, the E7 etc.? I don't think they "officially" count as modulations because they don't even resolve - they just hint at modulations by using ii7-v7. Are the G7, E7, A7 and Bb7 secondary dominants? By the definition I was taught, no.

    Yeah, I was just thinking it might be a trans-Atlantic thing. I see how Ed's definition makes sense, but I'm wondering what the official definition is? It doesn't really make much of a difference I suppose. I think of it conceptually anyway, rather than in terms of words - but now I'd be interested to know the official definition.
     
  15. Howard K

    Howard K

    Feb 14, 2002
    UK
    yes you're absolutely right, it matters not.. the definitions don't really differ that much...

    The only difference in what you & Ed are saying is whether the dominant chords between CMaj and FMaj here are secondary dominants or not?

    You agree that the only modulation in your progression is the final change into FMaj.

    It makes sense to me that these chords are secondary dominants as they are dominants without offically changing key - like Bruce said - so only when you resolve do you change key aand 'modulate'.

    So, if the progression had been:

    Dm7 G7 A7 Em7 Bb7 Fm7 Gm7 C7 Fmaj7.

    ...you'd have three modulations right?

    Have a good weekend all, I'm goimg home :)
     
  16. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Nah, in my book you got 1 modulation, really, and a few hints at modulations.
     
  17. moley

    moley

    Sep 5, 2002
    Hampshire, UK
    Fair point. I guess in Jazz it makes sense that, since new keys are so often implied (without resolution) in Jazz, it would still count as a secondary dominant.
     
  18. Howard K

    Howard K

    Feb 14, 2002
    UK
    Too hastey with copy & paste... I was walking home and realised I'd buggered this up...

    Dm7 G7 > E7 Am7 > F7 Bbm7 > Gm7 C7 Fmaj7.

    Now we have three modulations... with the V7 reslvoing to an i7.
     
  19. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    Yes - I think symphonists are more into progressive tonality - so that change will be resolved eventually - it may be 20 minutes later but it will eventually make sense!! ;)

    Whereas I think Jazz composers or arrangers can think along the lines of - "how I am I going to make this chord sequence sound different to the three hundred similar ones I played last night - I'll stick in this chord - it sounds alright - kinda Jazzy!! " :D