Theory question to the Bass Gods

[ThomasG]

Playing over a diminshed chord, how does the Locrian mode fit with that chord, since it is the related mode, or since the diminished chord is non-diatonic, is it technically correct to play the diminished scale instead of the Locrian ?

[JimmyM]

I've always believed in playing pretty much only chord tones over a diminished, otherwise it's no longer diminished. If you want to use Locrian, I guess it could work if you don't stay on the non-chord tones long, but the 7ths don't match up. The dim7 is actually a 6th while the Locrian 7th is a b7.

[liltommyg]

You could play any scale that has a minor third , flat fifth and flat seventh over the diminished and it would sound ok.
eg. (with c root)
C,D,D#,F#,G,G#,Bb,C

[ThomasG]

I go by Tommy G as well.

[JHL]

I play harmonic minor a halfstep up... sounds good to me :]

[Alun]

Originally Posted by ThomasG

Playing over a diminshed chord, how does the Locrian mode fit with that chord, since it is the related mode, or since the diminished chord is non-diatonic, is it technically correct to play the diminished scale instead of the Locrian ?

Strictly speaking, Locrian fits over half diminshed chords ( eg minor7b5 - R b3 b5 b7). It'll still sound OK but you are missing out on the double flattened seventh (same note as a major 6th) as JimmyM points out.

The harmonic minor a half step up will work fine as that contains the chord tones eg G# dim7 - G# B D F, and the harmonic minor a half step up is A B C D E F G#.

Either diminshed scale would also work:

half whole - G# A B C D Eb F G
whole half - G# A# B C# D E F F#

Cheers,
Alun

[DocBop]

Originally Posted by JimmyM

I've always believed in playing pretty much only chord tones over a diminished, otherwise it's no longer diminished. If you want to use Locrian, I guess it could work if you don't stay on the non-chord tones long, but the 7ths don't match up. The dim7 is actually a 6th while the Locrian 7th is a b7.

+1 The diminish is a double flatted 7th which enharmonicly a 6th.

Ya know I see so few diminished chords I don't work on them much. The key is are they a functioning dimisnished or not. Diminish chords are typically used as passing chord or to setup a chord. Like in Blues let's say your are going to a I7 or IV7 you will hear a I dim or IV dim just before the I7 or IV7. Sometime you hear a IV7 then #IV dim then I7. Old Freddie Green syle stuff you hear diminish chords as passing chords a lot. CMa7 C#dim Dmi7 D#dim Emi7 FMa7 type of thing.

Now many times you see a diminished chord it is really a dominant 7 b9 chord in disguise. First remember any note of a diminish chord can be the root since it is a symmetric chord. You remember that right?
So any note of a diminish chord might actually be the 3rd of a dominant 7b9 chord.

So C dimished is spelled C Eb Gb A (technically Bbb.) It could Ab7b9, B7b9 (Eb=D#), D7b9 (Gb=F#), F7b9. Sorry using enharmonic to try and make easier to see. Again any note of the dimished chord could be the 3rdd of a 7b9 chord. You look at them that why they many times are functioning as a V chord. There was a reason they did this a lot back when.

So for me if I see a diminish chord and it isn't lasting long then I will either play a dimished arpeggio or the diminish scale. If the chord is lasting more than a couple beats then I it is probably a 7b9 in disguise and I treat it as that 7b9.