Diminished Triad vs Diminished 7 on Piano
The C diminished triad and the C diminished 7 share 3 notes — C, Eb, Gb. From there, the C diminished 7 adds Bbb.
Piano, C3 to C5. Notes in this scale, low to high: C3 (root of C Diminished Triad and root of C Diminished 7), Eb3 (flat 3 of C Diminished Triad and flat 3 of C Diminished 7), Gb3 (flat 5 of C Diminished Triad and flat 5 of C Diminished 7), Bbb3 (double flat 7), C4 (root of C Diminished Triad and root of C Diminished 7), Eb4 (flat 3 of C Diminished Triad and flat 3 of C Diminished 7), Gb4 (flat 5 of C Diminished Triad and flat 5 of C Diminished 7), Bbb4 (double flat 7), C5 (root of C Diminished Triad and root of C Diminished 7).
Swipe the chart sideways to see all of it.
Both scales above are drawn on one piano keyboard in the key of C. Notes belonging to both are drawn as a split two-color dot, so the notes they share and the notes unique to each are visible in one picture.
How the formulas differ
Scale degrees are the key-independent way to compare two scales — these stay the same in every key, and they are what actually distinguishes one scale from another.
| Scale | Degrees |
|---|---|
| Diminished Triad | R · b3 · b5 |
| Diminished 7 | R · b3 · b5 · bb7 |
Notes in common
| Note | In Diminished Triad | In Diminished 7 |
|---|---|---|
| C | R | R |
| Eb | b3 | b3 |
| Gb | b5 | b5 |
Notes that differ
- Only in the diminished 7: Bbb (bb7)