I have heard 2 different schools of thought when describing the Locrian mode. The first one that I heard several years ago, when I first heard about modes is that it is a minor mode, despite its diminished 5th because its tonic is the seventh degree of the major scale and the seventh tends to have a diminished quality, especially in minor.
Now I hear more people saying that it is not a minor mode, it is its own mode, a diminished mode.
Here is the first school of thought that I heard:
MODE QUALITY ---- ------- Lydian MAJOR Ionian MAJOR Mixolydian MAJOR Dorian minor Aeolian minor Phrygian minor Locrian minor
This one kind of makes sense because Locrian is a modified minor scale.
And here is the more current school of thought that I keep hearing:
Mode Quality ---- ------- Lydian MAJOR Ionian MAJOR Mixolydian MAJOR Dorian minor Aeolian minor Phrygian minor Locrian diminished
This one implies that the modes are incomplete, at least to my eyes it does. To my eyes, this means there should be 3 diminished modes and 3 augmented modes just like how there are 3 major modes and in this school of thought, 3 minor modes. Also, the only connection between Locrian and the Diminished Scale is that the tonic triad is diminished in both cases. The Diminished Scale goes further than Locrian because the only triad you can make out of the Diminished scale, with each note being 2 scale degrees away is a diminished triad. To my eyes, basing the classification of the modes on the tonic alone as in the school of thought that says that Locrian is a diminished mode is not right. I would say that Locrian is a minor mode because it is based off of the minor scale.
But what do you think? Do you think Locrian is a diminished mode and not a minor mode? If so, why?