Basic question re dynamics spacing

[Andrew Bernard]

I have a piano staff, and two dynamics lines underneath. How does one increase or change the distance between the lower stave of the piano staff and the first dynamics line?

The following example was kindly provided by a list member some time ago to show how to increase the distance between the two dynamics lines, but no matter how much I read in the NR about nonstaff/relatedstaff/unrelatedstaff, all that happens is that my head spins, and the dynamics line stays put. What is the obvious setting that I am missing?

\version “2.19.23”

\score {

  <<

    \new PianoStaff <<

      \new Staff { a' a' a' a' }

      \new Staff { \clef bass a a a a }

    >>

    \new Dynamics

    \with {

      \override VerticalAxisGroup.nonstaff-nonstaff-spacing.basic-distance = #6

    }

    { s\p s s\f s }

    \new Dynamics

    { s\sustainOn s s s\sustainOff }

  >>

}

Andrew