Fretsmith, the question of "practical use" of modes is a good one. Its definitely a big subject. One thing that has helped me is hearing examples of artists using modes in ways that appeal to me. Joe Satriani's song "Cryin" has a part where he breaks into this beautiful Lydian progression... when I heard that, it really got me thinking about how to use modes melodically.
Speaking of Satriani, there was that YouTube lesson that I think Maggior linked to a while back, and during that lesson, Satriani mentioned the "Phrygian Dominant" scale. This intrigued me, and so I decided to check the scale out. I went through the same procedure that I described in this thread. First, I found out what the interval sequence was:
H A H W H W W *the "A" stands for "augmented": a whole step + a half step... in other words, three frets.
I then just played around with the scale on one string...
What I thought I'd do for you guys is post a demo of this experimentation process... I've created an audio file that you can just listen to on YouTube:
http://www.youtube.com/watch?v=fYneqG0g4ds&feature=youtu.be
Please note, this isn't a planned solo at all... this is just me letting my hand meander around doing whatever comes to mind... I just made it up as I went along!
Here's a break down of what's going on:
-we're in the key of D. The first thing I'll do is play the D Phrygian Dominant scale without any backing track. I'll go up, and then down, on one string so you can hear the notes clearly.
-next, I'll just add the open D string to drone the note and play the scale one more time... bear with it, things will get a lot more interesting in a moment.
-ok, the music kicks in, and right out of the gate I play the Phrygian Dominant scale up the B string... I intentionally over-shoot the high D by one fret (hitting the second degree) before resolving to the D. I meander down, go up one more time... hey man, this is all for you guys to be able to hear what the scale sounds like over the backing track... I know its boring, but its a great way to hear the entire scale over the music.
-I play the D Phrygian descending.
-After that, all bets are off. Fretsmith, this is kind of what you're asking about ("sure bud, that's the scale, but what GOOD is it??..." good question..).
-(1:16 of the song) now I'm going to use whatever I like, but I do try to keep coming back to the Phrygian scale.
-(1:34) ok Fretsmith, just for you... this is a little legato lick using D Minor Pentatonic, but I end it on the F# (I hope that's right!) kicking the solo right back into the Phrygian Dominant mode again.
-(1:57) I leave the Phrygian Dominant behind for quite a bit here. This is where theory can get a bit weird, but I think the riff might actually be D Locrian... I'm not thinking scales though as I play it... I just like the sound of that F, G, A flat thing.
-towards the end I drift back into the Phrygian Dominant along with Pentatonic Minor.
If I got any of theory wrong, I apologize. Its really not my strong suit but I'm trying to get a grasp on it. The Phrygian Dominant scale is quite fun to play!