How can I let the ambitus engraver ignore the key signature?

[David Kastrup]

Hi, the following is an excerpt from a systematic listing of accordion
chords with different ambitus.  The ambitus engraver should not heed the
first (arbitrary) key signature but rather engrave as though we were in
c major.

How do I do that?

\include "deutsch.ly"
\new Voice \with {\consists "Ambitus_engraver"}
{
\clef bass
#(set-accidental-style (quote forget))
\set Staff.printKeyCancellation = ##f
\key des \major
<<des, f, as,>>
<<des, fes, as,>>
<<des, f, ces,>>
<<des, fes, b,,>>
\key as \major
<<as, c, es,>>
<<as, ces, es,>>
<<as, c, ges,>>
<<as, ces, f,>>
\key es \major
<<es, g, b,,>>
<<es, ges, b,,>>
<<es, g, des,>>
<<es, ges, c,>>
\key b \major
<<b,, d, f,>>
<<b,, des, f,>>
<<b,, d, as,>>
<<b,, des, g,>>
\key f \major
<<f, a,, c,>>
<<f, as, c,>>
<<f, a,, es,>>
<<f, as, d,>>
\key c \major
<<c, e, g,>>
<<c, es, g,>>
<<c, e, b,,>>
<<c, es, a,,>>
\key g \major
<<g, h,, d,>>
<<g, b,, d,>>
<<g, h,, f,>>
<<g, b,, e,>>
\key d \major
<<d, fis, a,,>>
<<d, f, a,,>>
<<d, fis, c,>>
<<d, f, h,,>>
\key a \major
<<a,, cis, e,>>
<<a,, c, e,>>
<<a,, cis, g,>>
<<a,, c, fis,>>
\key e \major
<<e, gis, h,,>>
<<e, g, h,,>>
<<e, gis, d,>>
<<e, g, cis,>>
\key h \major
<<h,, dis, fis,>>
<<h,, d, fis,>>
<<h,, dis, a,,>>
<<h,, d, gis,>>
\key fis \major
<<fis, ais,, cis,>>
<<fis, a,, cis,>>
<<fis, ais,, e,>>
<<fis, a,, dis,>>
}
\new Voice \with {\consists "Ambitus_engraver"}
{
\clef bass
#(set-accidental-style (quote forget))
\set Staff.printKeyCancellation = ##f
\key des \major
<<des, f, as,>>
<<des, fes, as,>>
<<des, f, ces,>>
<<des, fes, b,,>>
\key as \major
<<as, c, es,>>
<<as, ces, es,>>
<<as, c, ges,>>
<<as, ces, f,>>
\key es \major
<<es, g, b,,>>
<<es, ges, b,,>>
<<es, g, des,>>
<<es, ges, c,>>
\key b \major
<<b,, d, f,>>
<<b,, des, f,>>
<<b,, d, as,>>
<<b,, des, g,>>
\key f \major
<<f, a, c,>>
<<f, as, c,>>
<<f, a, es,>>
<<f, as, d,>>
\key c \major
<<c, e, g,>>
<<c, es, g,>>
<<c, e, b,,>>
<<c, es, a,>>
\key g \major
<<g, h,, d,>>
<<g, b,, d,>>
<<g, h,, f,>>
<<g, b,, e,>>
\key d \major
<<d, fis, a,>>
<<d, f, a,>>
<<d, fis, c,>>
<<d, f, h,,>>
\key a \major
<<a, cis, e,>>
<<a, c, e,>>
<<a, cis, g,>>
<<a, c, fis,>>
\key e \major
<<e, gis, h,,>>
<<e, g, h,,>>
<<e, gis, d,>>
<<e, g, cis,>>
\key h \major
<<h,, dis, fis,>>
<<h,, d, fis,>>
<<h,, dis, a,>>
<<h,, d, gis,>>
\key fis \major
<<fis, ais,, cis,>>
<<fis, a, cis,>>
<<fis, ais,, e,>>
<<fis, a, dis,>>
}
\new Voice \with {\consists "Ambitus_engraver"}
{
\clef bass
#(set-accidental-style (quote forget))
\set Staff.printKeyCancellation = ##f
\key des \major
<<des, f, as,>>
<<des, fes, as,>>
<<des, f, ces,>>
<<des, fes, b,>>
\key as \major
<<as, c, es,>>
<<as, ces, es,>>
<<as, c, ges,>>
<<as, ces, f,>>
\key es \major
<<es, g, b,>>
<<es, ges, b,>>
<<es, g, des,>>
<<es, ges, c,>>
\key b \major
<<b, d, f,>>
<<b, des, f,>>
<<b, d, as,>>
<<b, des, g,>>
\key f \major
<<f, a, c,>>
<<f, as, c,>>
<<f, a, es,>>
<<f, as, d,>>
\key c \major
<<c, e, g,>>
<<c, es, g,>>
<<c, e, b,>>
<<c, es, a,>>
\key g \major
<<g, h,, d,>>
<<g, b, d,>>
<<g, h,, f,>>
<<g, b, e,>>
\key d \major
<<d, fis, a,>>
<<d, f, a,>>
<<d, fis, c,>>
<<d, f, h,,>>
\key a \major
<<a, cis, e,>>
<<a, c, e,>>
<<a, cis, g,>>
<<a, c, fis,>>
\key e \major
<<e, gis, h,,>>
<<e, g, h,,>>
<<e, gis, d,>>
<<e, g, cis,>>
\key h \major
<<h,, dis, fis,>>
<<h,, d, fis,>>
<<h,, dis, a,>>
<<h,, d, gis,>>
\key fis \major
<<fis, ais, cis,>>
<<fis, a, cis,>>
<<fis, ais, e,>>
<<fis, a, dis,>>
}


-- 
David Kastrup