What scale goes with the F#-7b5? I'm double checking what iRealPro has given

Question

iRealPro is giving the following scale for the F#-7b5 chord (F# minor 7th chord with flat 5).

F#, G, A, B, C, D, E

Can someone confirm that this is a valid scale for this chord? I'm asking because I thought the scale would be different (described below).

Here is how I understand things. F# major has 6 sharps

F#, G#, A#, B, C#, D#, E#

So for minor7, flat 5 I would use:

• A natural (flat 3rd) (due to minor)
• C natural (flat 5) (due to flat 5)
• E natural (flat 7) (due to dominant 7)

So a scale that could be played over the F#-7b5 chord is:

F#, G#, A, B, C, D#, E

Thanks for your help.

Answer 1

Since F#7b5 is part of the set of chords made up from notes of the G major scale, those very notes will work. It'd be called F# Locrian, centring on F#. Another way to regard this would be to use the notes of A jazz melodic minor, which are A B C D E F# G#. Again, centring on F#. There must be a theoretical reason, but it escapes me right now! But both sets of notes work fine.

The D/D#/E bit comes from Am blues, and again works well. Could be also called D/Eb/E, of course.

So now, we have the following notes which all 'work'. A B C D Eb E F# G G#. Maybe a simpler thing would be to say 'avoid A# C# and F'...

Answer 2

Both scales look valid to me, although your suggested scale will sound pretty exotic due to your C-D#-E pattern. The F#-G-A-B-C-D-E scale looks more conservative, as it's F# Locrian and therefore shares its notes with the G major scale.