A Major 13th (Amaj13)
Notes in A Major 13th
Inversions
Same notes as A Major 13th, with a different chord tone as the lowest note. Useful for smoother movement between chords instead of jumping around the keyboard.
Root position
A in the bass
1st inversion
C# in the bass
2nd inversion
E in the bass
3rd inversion
G# in the bass
4th inversion
B in the bass
5th inversion
D in the bass
6th inversion
F# in the bass
Open voicings
A close-position chord like A Major 13th can sound cluttered in the middle of the keyboard. Jazz players open it up by dropping one note down an octave, spreading the same notes wider without changing the chord.
Drop 2
A on the bottom
Drop 3
A on the bottom
Press A, C#, E, G#, B, D and F# together on the keyboard and you're playing A Major 13th.
A major ninth chord stretched all the way to the thirteenth, rich and expansive on paper though almost always voiced with several notes left out in practice. What survives keeps the warm, settled character of a major ninth chord with an even fuller top end.