Improvising over substitute dominants?

Hi, so I have been combining the IFR numbers method with the theorical jazz way of changing scales for every single chord and it’s been fun, but I’ve sort of reached a roadblock where it feels like I cannot really mix both of them; This topic is called substitute dominants.

So, lets say we’re playing in C major (meaning that C is the 1, D the 2 and so on) and we have a very common progression like Db7, Dm7 and Cmaj7, which would be translated as bII7, iim7 and Imaj7 in the IFR numbers method.
Now, I’ve been taught to use a mixolidian #11 scale when improvising over a sub-dominant chord, which would in turn en up on the following scale:

Db7 Mixolidian #11: Db - Eb- F - G - Ab - Bb - Cb
In IFR Numbers: b2 - b3 - 4 - 5 - b6 - b7 - b1

It just seems so outside the key that it actually feels counter productive to keep thinking of the C as the tonic center, but the whole point of mixing the IFR with the traditional Jazz way of playing is to avoiding leaving the main scale unless strictly necessary (modulations). I’ve been able to play secondary dominants with this approach because you just have to change the b3 of the chord into a major 3rd; meaning that for VI7 you just have to change one note of the scale; in this case you would change the 1 to a #1 (because 1 is the b3 of 6) and that would leave us with a A7 Mixolidian b6 without even having to stop thinking about the C major scale.

So I don’t really know how to keep this way of playing with the sub-dominants. Should I just play the scale of the chord they’re doing the substitution for? Meaning that in the case of Db7 I could just play G mixolidian. Or should I just memorize the 5 scales that happen with these chords? Meaning that I would need to memorize the changes that the bII7, bIII7, bV7, bVI7 and bVII7 create over the tonal center? I’ve also thought of only changing the tonic, 5th and 7th of the chord (making Db7: b2 - 3 - 4 - 5 - b6 - 7 -b1) but that would create a mixolidian #9, #11, #13 and I don’t really know if that sounds good (I’ll have to test it out).

I don’t really know what I should do, but these kind of theorical problems are fun.

I would really appreciate your imput :grin:

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This is way out of my league. I think tagging David Reed ( @ImproviseForReal ) in the hope of finding out his take on the subject is probably a good idea?

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Hi @Asuryan, thanks for posting this thoughtful question. I love that you are exploring different ways of thinking about harmony, and I would always encourage you to adopt whatever mental models truly serve you best in the moment of improvising.

That choice of model has important consequences. So we can’t dictate a single “best” way of thinking about harmony for everyone. What’s best for you will depend on how you want to make music, and what kinds of things you need to see clearly (and quickly).

For example, if you are very attracted to somewhat abstract improvisation with scales and other patterns (e.g. the styles of John Coltrane or Wayne Shorter), then probably it will suit you best to think of that note b2 as your new “note 1” and just mentally build your lydian dominant scale there, just as you have outlined.

On the other hand, if you are more attracted to lyrical, melodic improvising (e.g. the styles of Chet Baker, Miles Davis, or Thelonious Monk), then you will definitely want to learn to see every note you play on a single map of the musical landscape. This is what you are doing with the second scale representation above (what you’re calling “IFR Numbers”).

One idea to consider is that these tonal numbers are true whether we are aware of them or not. For example, regardless of your mental model, whenever you play the notes G, Ab and Bb in the key of C, you are in fact playing notes 5, b6 and b7. And these notes can be connected lyrically with all of the other notes available to you. This is why it’s so empowering to become aware of what notes you’re actually playing relative to the overall harmonic landscape. Changing keys every measure might be an easy shortcut for finding a bunch of notes that sound okay. But it severs the connection to the notes you were just playing in the previous measure, making it much harder to connect your ear to what you’re playing.

But music is an art form with infinite possibilities, and there is no right or wrong way to make music. So ultimately you’re the only person who can decide which skills are going to be necessary for the way that you want to make music. The only tip I can give you is that learning to see all of these notes relative to the overall key of the music isn’t nearly as hard as you’re making it sound. You’ve already done the hardest part yourself which is the analysis. Now all you have to do is practice that mental model when you are improvising. To cement this learning quickly, the best practice tool would be a jam track that alternates between the 1 chord and the b2D chord, and nothing more. That way you can spend the whole time practicing your ability to visualize those exotic b2D sounds relative to the overall key. And if you replicate this jam track in all 12 keys, this will further solidify your mastery of the tonal numbers by forcing you to picture these things quickly in all different keys.

If you decide you want to master this skill with this particular chord, the one suggestion I would make is to drop the symbol “b1” and instead call this “note 7”. You are absolutely right that the theoretical origin of this note choice is to lower note 1 by a half step. But musical improvisation happens in time and we can’t afford to be slowed down by extra calculations. So for the improviser, it’s always helpful to reduce these concepts to their simplest final result. So I would just suggest that you practice the b2D scale as follows:

b2 b3 4 5 b6 b7 7

Another argument you might want to consider is that mastering the scale above will continue to pay dividends over the course of your entire life. You only have to put the work in once, but then you’ll reap the benefits every time you encounter this chord in a tune (which is quite often), and also every time that YOU choose to impose these sounds in your own improvising. And again, learning these Mixed Harmony chord scales in tonal numbers is nowhere near as hard as you’re imagining. I’m quite sure that you could master this b2D scale in a single day if you really put your mind to it. So truly both options are available to you!

(And thanks to @DavidW for tagging me!)



I have also been interested in this idea of mixing some of the denser jazz harmony with IFR and I’ve found that although it seems daunting at first, sticking to the tonal numbers as related to the key at all times is what I feel will serve me in the long run.

One of the concepts I was having trouble conceptualizing for a while was playing an altered tonality over the 5 chord back to 1, but it just took me slowing things down and exploring the 5 chord with these unfamiliar tonal number names, in this case, I conceptualized it as
5 b6 b7 b1 b2 b3 4

Flat 1! It seemed super foreign for me to think about it this way, but after tracing over those pathways I was able to eventually get them into my mind and I’m glad I did. Additionally, when you approach it this way when keeping the tonal numbers the same, when you start working with tritone subs, for example, the b2dom chord in this case, you can simply keep the scale you already learned to play over the 5 chord the same! More bang for your buck!

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Hi @Jaden_Kim! Wecome to the community! Just a quick question: why do you have to look at it as b1 instead of just 7?

Hi @Jaden_Kim. Welcome to the forum. :smiley:

Thanks for the welcome! It’s funny you ask actually as soon as I published my response I saw David’s answer and saw he recommended against thinking of it as b1. I originally had put a high value on making sure that there was only 1 of each number but it definitely does make more sense to keep it as 7, especially if the chord we’re going to uses 7 like the one chord does. I guess that’s the importance of avoiding dogmatic thinking haha. Time to get comfortable with a map with two 7s and no 1 haha