LadyDpiano: You Can Accompany Yourself

C Δ7 , or major seventh chord on C About this sound Play ( help · info ) . (Photo credit: Wikipedia)

Triads are built from scale tones. There are both Major seventh and ninth chords (Maj7 or +7 and Maj9) and Minor seventh and ninth chords (m7 and m9):

CDEFGABCDE

C6 = CEGA

C7 = CEGbB

Cmaj7 = CEGB

Cmaj9 = CEGBD

Cm6 = CEbGA

Cm7 = CEbGBb

Cm9 = CEbGBbD

Cm(maj7) = CEbGB

When playing these chords from music with chord symbols, you can play the chord root with your left hand (try to hang around middle C with your left thumb(, and chord tones 3 and 5 with your right hand. From this position, it is possible to play every chord (major, minor, seventh, diminished and augmented):

C = CC/EG

Cmaj7 = CB/EG

C7 = CBb/EG

C6 = CA/EG

Cm(maj7) = CB/EbG

Cm7 = CBb/EbG

Cm6 = CA/EbG

Cdim = CC/EbGb

Caug = CC/EG#

Try playing these voicings in many different keys.

Wikipedia says:

In music composition and arranging, a voicing is the instrumentation and vertical spacing and ordering of the pitches in a chord (which notes are on the top or in the middle, which ones are doubled, which octave each is in, and which instruments or voices perform each). Which note is on the bottom determines the inversion.
Voicing is "the manner in which one distributes, or spaces, notes and chords among the various instruments" and spacing or "simultaneous vertical placement of notes in relation to each other."

You might be interested in these articles:

Voicings at Jazz Center

The ABCs of Chord Voicings.html

Two Handed Voicings

Why Don't A Lot of Songs Transpose Well?

Now, I met this very cool guy on FaceBook Jerald Simon, and received tons of songs for free awhile back. Right now, Music Motivation is offering free music for piano students and teachers, here

You may be interested in purchasing some teaching tapes about chord structures and names of chords; Chords 101 and 102

Warmly,