E Locrian scale on the guitar fretboard
The E Locrian scale is made of E (the root), F (minor second), G (minor third), A (perfect fourth), Bb (diminished fifth), C (minor sixth) and D (minor seventh). The fretboard shows every one of them across the neck in standard tuning (E A D G B E), and plays them back so you can hear the scale.
The Locrian mode is the seventh mode of the major scale, with a lowered second and a lowered fifth. The lowered fifth takes away the stable fifth above the root, so it sounds unsettled. It shares its notes with a major scale a semitone above.