I have been asked to transcribe an orchestral piece for a brass band (all sort of brass + alto sax + tenor sax + drums).
The orchestral piece contains a harp arpeggio part, and I really do not know how to transcribe it. At the beginning of the piece, the harp arpeggio is the only part that defines the tune harmony. Can someone give me a hint ? Is there a well know way to do it ?
since I do everything by ear, I think in cases like this,
we have to be put our creative hats on.
I would use percussion instruments.
The first (lowest) notes would be played by the marimba,
then about half way through the glissandi,
the glockenspielberg would be added.
This is where your skill as an orchestrator comes into play. Certain things can be transcribed exactly, others can't. Without hearing your specific piece, it's hard to make an accurate suggestion. But use the instruments you have on hand to create the same effect, even if you don't duplicate every note that the harp arpeggio covers.
A brass pyramid with staggered entrances, possibly using different mutes for added color might be an option.
And as Dan suggested mallet percussion can be used for this type of thing. A Vibraphone has a "let ring" quality to it that can be used in place of a harp.