
\version "2.7.13"

\header {

texidoc=" Auto change piano staff switches voices between up
and down staves automatically rests are switched along with the coming
note. When central C is reached, staff is not yet switched (by default).

"
}
\layout { raggedright= ##t }

\context PianoStaff <<
  \context Staff = "up" {
    \autochange  \context Voice = VA << \relative c' { g4 c e d c r4 a g } >>
  }
  \context Staff = "down" {
    \clef bass 
    s1*2
  }

>>

