The F#7 is the V chord in the key of B Major, and it is a chord with some built-in dissonance. Therefore, you're not going to make it any more dissonant unless you play something that is not even close to being in the same key. B Harmonic Minor is close enough that it doesn't introduce any additional dissonance to the F#7 chord.
Also, and perhaps more importantly:
Since the tone center intervals (the 1, 3, 5, and 7 of any chord) are the ones that anchor your sound over the chord being played, if you examine the tone centers of F#7 and B Harmonic Minor, you notice something else.
F# A# C# E
B D F# A#
You can readily see some similarity in that both contain F# and A#. The F#7 chord comes from the key of B, and that is why B sounds good over F#7. The D isn't usually part of an F#7 chord, but D# would be the major 6th if you played F#7add6(or 13). If you did play that F#7add6 chord, then the D in the B Harmonic Minor would probably not sound very good! Since you are playing a D in your soloing, you are, in effect, secretly making that F#7 into an F#7 with a flatted 6th. All the other notes from the B Harmonic Minor scale simply add a different flavor than you would get from any other B Major Mode.
As you can see, I like to analyze everything too. Hopefully this stuff makes sense and clear things up a bit. |