Compare
Double Harmonic vs Persian
Both have ♭2 + ♭6 + ♮7. Persian adds ♭5; doubled harmonic keeps the ♮5. Two Middle-Eastern colours one semitone apart.
Double Harmonic
R
♭2
2
♭3
3
4
♭5
5
♭6
6
♭7
7
Persian
R
♭2
2
♭3
3
4
♭5
5
♭6
6
♭7
7
What's different
Only in Double Harmonic
5
Only in Persian
♭5
In both
R♭234♭67
Other comparisons