\version "2.19.39"

% \include "text-spanner-id.ly"

\score {
    <<
        \new Staff <<
            \relative c'' {
                a1-\tweak bound-details.left.text "ON" -\tweak bound-details.right.text "OFF" \startTextSpan |
                << { s2. <>\stopTextSpan } a1 >>
            }
        >>
        \new Staff {
                \repeat unfold 8 c''4
        }
    >>
}