Understanding Triad Cycles: C Major over Db and Bb Bass
What was the question?
Lanny asked for a clarification regarding the "essential building blocks" triad lesson. Specifically, he wanted to understand the application of using a C major triad in relation to B flat and D flat. He wasn't sure if the instruction meant using those specific notes or playing the C triad over those bass notes (24:50).
The core idea (in plain English)
The concept refers to playing a C Major triad over specific bass notes to create tension and specific harmonic colors. It is not just about the scale notes; it is about the vertical result of mixing the triad with a new root.
When you play a C Major triad over a Db bass note, you are creating a Db Diminished Major 7 sound. This works because of the "Auxiliary Diminished" concept. In a diminished chord, any note a whole step above a chord tone can function as a tension. If you take a Db diminished triad and move the notes up, you can derive a C Major triad. This implies a resolution or a specific tension often used when ending a tune (26:49).
Fretboard breakdown (what to play)
Here is how to visualize these triad relationships:
C Major Triad over Db Bass (26:49)
Function: Db Diminished Major 7 (Auxiliary Diminished).
Context: Often used as a passing chord or a "surprise" ending chord (e.g., C Major ending resolving to this sound).
Why it works: It raises the chord tones of the diminished form to create a major triad "upper structure" sensation.
C Major Triad over Bb Bass (30:49)
Function: C7/Bb (3rd inversion of C7) OR Bb13(#11) depending on context.
Context: Dominant function.
Why it works: The C triad contains the 9, #11, and 13 of the Bb root, or simply the Root, 3rd, and 5th of C dominant over its b7 bass.
Common mistake to avoid
Do not view triads as static shapes that only work on their own root (e.g., C triad over C bass). The biggest mistake is ignoring the "Cycle of Triads." You should be able to move triad shapes through a cycle without jumping around the fretboard. A good sound should resolve logically to the next chord, not just exist in isolation.
A 10-minute practice assignment
Practice the "Cycle of Triads" foundation.
Play a C Major triad.
Change the bass note to Db and listen to the tension (Diminished Major 7 sound).
Change the bass note to Bb and listen to the dominant quality.
Resolution: Ensure that after creating this tension, you resolve the voice leading to a stable chord nearby.
(Assignment context: 24:50 - 32:14)
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