function to recognise voice crossings?

[Eef Weenink]

Hello all, 

I write mostly arrangements where I bring a melody voice down to the double 
bass (my instrument :-)) 

Double bass is written an octave higher then sounding, so a lot of times, the 
score lookes OK, but in fact there are voice crossings between lefthand of 
piano and the double bass (what gives unwanted/unpleasant voice crossings. 

To check this, I transpose the double bass voice down an octave and manually 
check the boths voices. 

Wonder if there is a function in lilypond to do this fastly. Like the coloured 
noteheads when checking a voice against the ambitus of an instrument. 

Regards, Eef