Watch the Gb add#9 online guitar lesson by Brad Carlton from Guitar Lab: Open String Universe
This chord voicing is achieved by moving the lowest four voices of the open Em form up 3 frets. The first and second strings(voices) remain open and thus extend and/or alter the basic minor chord which is always occuring in voices 6 through 3.
The voicing for this chord is as follows(from low to high in pitch):
6th string(voice) 1
5th string(voice) 5
4th string(voice) 1
3rd string(voice) b3
2nd string(voice) 3
1st string(voice) 6(13)
Analyzing this chord against the 6th voice (as the root) reveals the name as G6 add#9(incomplete G13#9).
The applicable scale(s) for soloing over this chord would be:
G half-whole diminished
1 b2 #2 3 4 5 6 b7
G Ab A# B C# D E F
Notice that the half-whole diminished scale does not contain a natural 5 which is occuring in voice 5 of the chord.