Part 11: Modes with an audible reason · Lesson 106 / 117
Optional colour: Locrian lowers the fifth too
Optional extensionInspect a diminished tonic rather than forcing a familiar major/minor expectation.
B Locrian uses B–C–D–E–F–G–A. Relative to B, its formula is 1–b2–b3–4–b5–b6–b7. Its tonic triad is B–D–F, a diminished triad.
That lowered fifth distinguishes it from the major- and minor-tonic examples studied so far. A B-centred drone or repeated B reference helps you inspect the intervals, even though the tonic triad does not have the perfect fifth you may expect.
Play B–C–B to hear the lowered second, then B–F–B to hear the diminished fifth. Keep these as separate comparisons. The goal is understanding its ingredients, not immediately writing a convincing full Locrian piece.
The notes match C major, but that fact alone does not establish B as home. The same requirement for a supported tonal centre applies. This is an optional listening and construction lesson, not a prerequisite for enjoying other modal sounds.
Hear it
Locrian
Audio fileFour-beat count-in · 60 BPM · Warm sampled electric guitar. Listen once before playing along.
A concrete example
B Locrian tonic triad: B–D–F. Its fifth is F, not F#. Its second is C, not C#.
Try it, slowly
- Play B–C–B against B.
- Compare F and F# above B.
- Explain how B–D–F differs from B minor.
Check one idea
Why is the Locrian tonic triad diminished rather than simply minor?
Show the explanation
It has both a minor third D and a diminished fifth F above B. A B-minor triad would contain the perfect fifth F#.
A good place to stop
You can identify the lowered fifth and avoid describing the mode as only another minor box.
Return to the example after a short break. A clear explanation matters more than speed.