Where to get preprocessor?

[Henk Metselaar]

Hello,

I installed MusixTeX and am impressed both by the output and by 
the amount of work you have to go through.
I understand a preprocessor can assist me here. Currently I just 
want to write out sheet music for my instrument, trumpet. Which 
pp should I use, then and where can I get it?
TIA,
Henk