Modifying the Ottava spanner slope
It is possible to change the slope of the Ottava spanner.
\relative c'' { \override Staff.OttavaBracket.stencil = #ly:line-spanner::print \override Staff.OttavaBracket.bound-details = #`((left . ((Y . 0) (attach-dir . ,LEFT) (padding . 0) (stencil-align-dir-y . ,CENTER))) (right . ((Y . 5.0) ; Change the number here (padding . 0) (attach-dir . ,RIGHT) (text . ,(make-draw-dashed-line-markup (cons 0 -1.2)))))) \override Staff.OttavaBracket.left-bound-info = #ly:horizontal-line-spanner::calc-left-bound-info-and-text \override Staff.OttavaBracket.right-bound-info = #ly:horizontal-line-spanner::calc-right-bound-info \ottava 1 c1 c'''1 }