In a recent trombone sectional for the band I play in, sectionmate P (who is a recent convert from the viola) expressed confusion at sectionleader J’s description of our need to “play behind the trumpets”.
P’s first thought, apparently, was “Of course we play behind the trumpets, we sit behind them!”
Upon further discussion, P revealed that he would prefer the preposition below there, because of the idea of a “lower volume level”.
It brings up an interesting viewpoint on how we understand musical texture as spatial positioning. I tend to use “behind” in the same way that J does — namely that when one section or melody is supposed to be prominent, I have the image that it is “stepping up” or “coming forward”, as a soloist walking out in front of an ensemble.
To say “below”, even as it implies a volume level, also (to me) means the pitch — and of course the trombones play below the trumpets, they are a lower pitched instrument! Of course, I can see how one instrument may be “above” another in importance, just as the way with “behind” indicates forward and back.
It makes me curious — are there groups of instrumentalists who regularly envision musical texture laterally (front and behind), and those who view it vertically (above and below)? Is it separated by instrument, instrument family, background in musical ensembles… or is it by region or teacher? This would be an interesting study to conduct with the right setup.