I'm trying to learn the fretboard and where each note is on the fretboard and I'm having some confusion on why we only hit two notes on one string, while on others we hit three notes per string. My example comes from:
http://www.ultimate-guitar.com/lessons/for_beginners/learning_the_fretboard.html

Why on the E Phrygian scale do we only hit the G and A notes on the G string vs. hitting the G, A, and B notes on the G string? I understand we want to end the scale on the E note to complete the scale, but how do we know what string to only play two notes vs. three notes on? Is it something people just memorize? It seems there must be some music theory I'm missing. Thanks for the help!

E Phrygian

e|-----------------------------0---------------------------
B|-----------------------0-1-3-----------------------------
G|-------------------0-2-----------------------------------
D|-------------0-2-3---------------------------------------
A|-------0-2-3---------------------------------------------
E|-0-1-3---------------------------------------------------

E F G A B C D e f g a b c d e

Here's my second example since the above E phrygian makes me think our goal is to hit each strings open note throughout the scale. In A Aeolian why do we hit the G and A notes on the D string and not the G, A, and B notes on the D string and then the C note on the G string? And if it comes down to being because we need to end on the A note at the high E, then why not just hit two notes on the B string instead? Hopefully my explanation of where I'm getting confused at is enough for other people to understand my confusion.

A Aeolian

e|------------------------------5---------------------------
B|------------------------5-6-8-----------------------------
G|------------------4-5-7-----------------------------------
D|--------------5-7-----------------------------------------
A|-------5-7-8----------------------------------------------
E|-5-7-8----------------------------------------------------

Hopefully by filling in this gap in my learning experience I'll have an Ah HA! moment.
Last edited by pelesmk at Sep 12, 2011,
You can play any scale really in a 3 note per string fashion.

e|------------------------------5---------------------------
B|------------------------5-6-8-----------------------------
G|------------------4-5-7-----------------------------------
D|--------------5-7-----------------------------------------
A|-------5-7-8----------------------------------------------
E|-5-7-8----------------------------------------------------

VS

e|---------------------------------------------------------
B|-----------------------------6-8-10---------------------------
G|---------------------5-7-9----------------------------------
D|--------------5-7-9----------------------------------------
A|-------5-7-8----------------------------------------------
E|-5-7-8----------------------------------------------------

They are the same notes, however your root is just not on the E string again.

Also, you can play the "two note" section on either the G or D string, by moving the 2nd (B) to either the 4th fret of the G string, or the 9th fret of the D string.
Where's Waldo?
the answer is - it doesn't matter.

Play the notes anywhere you want, that's the whole point of the guitar - the same notes appear in different places. There is no "goal" inherent to scales themselves, they're just a tool, the goal is to make music with them.
Actually called Mark!

Quote by TNfootballfan62
People with a duck for their avatar always give good advice.

...it's a seagull

Quote by Dave_Mc
i wanna see a clip of a recto buying some groceries.

stuffmycatswatchontv.tumblr.com
in e phrygian on the g string hitting the next note to make it have three notes every string would mean that you repeat the B note on G string 4 fret and open B string
I am going to explain this in C Major, not any modes, as its much easy to understand.

First- you can learn the scales three note per strings, its just a different shape with the same notes.

The formula for a major scale is T T ST T T T ST, so if you go across the strings using that formula, thats just the way it kind of sits.

There is no technical or scientific reason for it.

As for knowing where to do 3 notes and where to do 2 notes, you have to learn all the scale shapes. There are 5 major scale shapes. But memorizing them all you will get this down.

I think thats answers a bit vague, but hopefully that helps.
It is all about thinking in boxes.
In the first example, you stay in the first position. You can hit the next note of the scale without changing position. You could also play G string, 4th fret instead of an open B string, it wouldn't change the note or anything else (except for a slight difference in the tone).

It is the same thing. You could, and I personally think, it is the better way, play the B on the G string on the G string, so 9th fret in order to make the fingering easier and not changing the position.

So always keep in mind: you can play one note on different strings and it won't change the pitch of it. If you've got the 24 frets on your guitar, try playing an open high e string, and then play it on the B, G, D, A and low E string; you will notice that you have the exact same note 6 times on the fret board
Quote by BSPDelta09
It is all about thinking in boxes.

I disagree. You should be able to fluidly move throughout the fretboard and know exactly where every note is that you would need to hit. You shouldn't have to be playing, and want to hit a note so you have to shift your whole hand down to find a certain "box" that you want to hit it in.
Where's Waldo?
Thanks for all the quick replies. The idea that it was a shorter interval, staying in boxes, scale shapes, and covering a couple quick lessons at musictheory.net on major scale and intervals it's starting to fill in the blanks I was having vs. just plucking strings and notes blindly, because the tabs said to.
Basically, because of the nature of how the G and B string are only a major 3rd apart instead of a 4th, and hence standard tuning isn't purely symmetrical, traditional scale boxes often have only two notes on the G or B string. And in the case of the open boxes you gave, it basically takes advantage of playing opens when they are available, I.E. for E phrygian you don't have to play the 4th fret on the G string because the open B string is the same note.