Presence

I just got a worried email from some performers concerned about some dynamics in a piece.  In the score, I have a flute playing at a moderate dynamic and suddenly a snare drum rolls over the flute for a measure of forte, after which the flute continues on, more or less as before.  This interruption occurs a few times.  The players were concerned that, during the drum roll, the flute would be inaudible, so they suggested upping the flute's amplitude to match the drum.  I wrote them back not to worry, as the flute, through the continuity of its line and its distinctive character, would be perfectly present, if not literally "heard" and so attempting to balance the two instruments was unnecessary.