Secondary Dominants, Tritone Subs

Discussion in 'Ask Michael Dimin' started by stephanie, Sep 16, 2001.

  1. stephanie


    Nov 14, 2000
    Scranton, PA
    Hello Mike and everyone, hope you are all well.

    I posted a thread sometime ago here about Key Centers and I was working in Gary Willis' book "Fingerboard Harmony For Bass". I know someone else had this book and helped me (Bruce, I think?). Needless to say, I am still working in that book and I have hit another problem:

    I am confused on what exactly secondary dominants and tritone subs are. They give the definitions but they are not clear enough for me. :( I've been working in the sections "Choosing A Key Center" and "Three/Four". So when the book goes on about memorizing chord progressions and figuring out the hand positions for the progressions I'm at a lost. I've been reading these pages over and over again, but they are still confusing. I couldn't find a thread here that clearly defines what they are either.

    Any help on this would do. Sorry if this post was confusing. For those who have the book it's basically pages 60----> that I'm having trouble with.

  2. Phil Smith

    Phil Smith Mr Sumisu 2 U

    May 30, 2000
    Peoples Republic of Brooklyn
    Creator of: iGigBook Sheet Music Manager
  3. stephanie


    Nov 14, 2000
    Scranton, PA
    Thanks Phil! :) I read over that, a little confusing to me still, but oh well....I will have to take more time out to look it over better.

    Thanks again
  4. Mike Dimin

    Mike Dimin Inactive

    Dec 11, 1999

    Sorry it has taken so long for me to respond. let me try to put in simple terms (and give you some musical examples).

    1. Secondary Dominant: In jazz, musicians will often use "reharmonization" techniques to add interest and variation to the music. The Secondary Dominant is one such reharmonization technique (although you will see it in other forms of music). The concept of the secondary dominant is to preceed any given chord by it's dominant chord. Since the dominat chord outlines the key or tonal center that you are playing in (as per Willis' book), this secondary dominant chord would be the "V" of the temporary tonal center. For example if you are playing in C major and come across an E7. The E7 is not diatonic or "in the key" of C. If we look at Willis' book, we would see that the E7 would define the key of A or A minor. The E7 temporarily changes the tonal center to A minor. This is the concept of the Secondary Dominant. The reason that the dominant chord defines a key or tonal center is due to the tritone that is unique to the domiant 7th chord (not actually unique, but good enough for this discussion). The tritone is the interval of an Augmented 4th (or diminished 5th). In the dom 7th chord it is represented by the "guide tones" or the 3rd and 7th degree of the chord. In an E7 the tritone is the G# and D. Go to a paino and play the G# and D together. Hear the tension. Play the G#and D together again and now resolve each note inward to the A and C# (1st and 3rd of the A maj chord). Hear the strong tensions and resolution you have created. That is the reason that the dom. chord is so important and powerful. This leads us to .....

    2. Tritone Substitutions. The interval of the tritone spilts the octave in half. Upon further reflection we see that there are 2 domiant 7th chords (a tritone apart) that share the same tritone. If we look back at our E7 chord (E,G#,B,D) and the dom 7th chord a tritone away - Bb7 (Bb,D,F,Ab) we see that the two chord share the D and the G#/Ab. We can therefore substitute one chord for the other. Where this really works nicely is in the standard jazz progression II-V-I. Normally this progression would be B-7, E7, Amaj. If we use the tritone substitution for the DOMINANT chord, we now have B-7, Bb7, Amaj. We still have the same tritone resolution, but we also have a wonderful chromatic, voice led bass line.

    Hope this helps.

  5. stephanie


    Nov 14, 2000
    Scranton, PA
    Thanks for the help. I've been working in this book for so long, I'm hoping to finish it soon, just keep hitting these stumbling blocks. Your explanations cleared up a lot of things, Mike. Thanks. :)

    Be well,