Locrian

The locrian mode is the seventh mode of the major scale. The intervals of the locrian scale are as follows:

1   b2   b3   4   b5   b6   b7

It is a minor scale, but with a b5 and a b2. The scale is built off of the diminished chord and is therefore the most, well, diminished sounding! It is as minor and sad as you get in diatonic music. 

This scale is extremely rare to hear as a tonic. It really only exists in Slayer-esque speed metal scenarios where you aren't hanging on anything long enough to become unstable, which the scale (and the diminished chord itself) naturally happens to be.

Play a diminished chord or a mi7(b5) chord. Can you really make this sound like home? No, you really can't because it sounds unresolved and unstable. 

The challenge, therefore, is to sell this instability and harness the scariness of it. 

When we build 7th chords off of the locrian scale we are left with the following:

I mi7(b5)   bIIma7   bIII mi7   IV mi7   bVma7   bVI 7   bVII mi7

Again, there aren't really any common locrian progressions, but anytime you are trying to sell a diminished chord as home, go locrian.

Try these:

• I dim - bVI ma
• Imi7(b5) - bII ma7

Below are the five patterns of the locrian scale and jam tracks of the above progressions including a mi7b5 vamp. Start with a pentatonic, then add the b5, then the rest of the locrian scale. Really jack up the distortion and let your picking hand fly.

Jam Tracks:

1.  D locrian - Dmi7(b5) vamp

2.  C locrian - Idim - bVIma

3.  A# locrian - Imi7(b5) - bIIma7