One of the most-often-used re-harmonization of the V7 is done by replacing that chord with the subV7.
Which chord is the subV7
The subV7 is a dominant chord a tritone away from the V7 (also a half step above the tonic or I)
Why does the subV7 work as a substitute of the V7?
There are two main reasons why this chord is such a perfect substitute for the V7
- The guide tones (3 & 7) are the same in both functions.
The 3 & 7 in the subV7 are the 7 & 3 in V7. The guide tones are the notes that give the chord its characteristic sound. In dominant chords, the guide tone (3,7) are a tritone apart. The tritone is an interval with lots of tension, [it used to be called “The devil’s interval” back in the middle ages] , which wants to resolve by moving each note half a step in opposite directions, thus turning into a major 3rd (when resolving inward) or a minor 6th (when resolving outward)
Example: In the key of C • G7 is the V7 • 3rd is B • 7th is F (since it is a flat seventh in dominants). B-F is a tritone. It wants to resolve either: inward to C-E (major 3rd) or, outward to Bb-Gb (minor 6th). A tritone apart from G is Db which would be the root of the subV7 in the key of C, and the guide tones in Db are F (the 3rd) and C flat (the flat 7th, which is B). Thus, we can resolve those two notes, as if we were in G7, to E and C, the tritone then resolves as expected in the key of C from Db7.
- The root of the subV7 is a half step above the I (tonic)
The bass-line for a V7-I progression moves down a perfect fifth (which is a very powerful bass movement).
When substituting the V7 with the subV7, the bass-line for the subV7-I is moving a half step down (which is as strong as the perfect fifth). Substituting the V7 with the subV7 gives us a strong bass-line that resolves tension well.
Here are the two examples using Mapping Tonal Harmony Pro 5 to view the different paths taken when using the V7 and/or the subV7 in the progression IIm7 – V7 – I (2-5-1)
Can you hear and identify all intervals, triads and sevenths? Can you find the right one in a group of up to six different ones?
Can you identify them in context, embedded in the background music?
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mDecks Ear Training 1 focuses on Intervals, Triads and Sevenths
A set of circles containing musical elements in a class (interval, triad, rhythm, melody, etc) will be shown on the screen. You will have to listen to them and decide which one contains (or creates) the requested musical element.
Elements will be presented alone and in context: In advanced stages you will have to find the circle that makes the requested element when combined with the background music!
mDecks Ear Training will guide your study step by step, increasing the level’s difficulty as your hearing improves from Beginner to Master level.
There are 6 Stages, each stage contains 6 Levels: Listen&Learn, Beginner, Intermediate, Advanced, Expert, Master, and each level contains a set of exercises that you will need to conquer to access the next one. More than 120 sets of exercises!
In each exercises the app detects how well you are performing to guide you through the entire set of levels and stages. Once you’ve finished the entire app you will be a Master at recognizing intervals, triads and sevenths
Stages in mDecks Ear Training 1:
Stage 1: Intervals (melodically up, melodically down, harmonically)
Stage 2: Intervals in Context (several soundtracks at different levels in all keys)
Stage 3: Triads (melodically up, melodically down, harmonically)
Stage 4: Triads in Context (several soundtracks at different levels in all keys)
Stage 5: Seventh Chords (melodically up, melodically down, harmonically)
Stage 6: Sevenths in Context (several soundtracks at different levels in all keys)
Guided Study Mode: The app controls the levels availability based on your progress
Free Study Mode: You can play any stage and level freely.
Two Play modes: You may choose between to play modes
1. Drag over: you listen to the sounds behind the circles by dragging a play button over them and then tap to make your choice.
2. Tap & Hold: you listen by tapping and holding on a circle and you make your choice by double tapping.
Endurance Mode on/off: The next exercises starts immediately after.
Music Notation on/off: You may enable music notation (when available) if you want to recognize musical elements using prefect pitch (if you have it) and/or music theory (by recognizing the requested item from the staff)
Wave String: You may view the signature wave of an interval, triad or seventh if you want to use a visual input as an aid in memorizing the sound.
Volume Balance: control between the background music (context) and the sound behind the circles.
Statistics: A record of your performance is kept in the stats panel (one for the free mode and one for the guided mode)