Essentially the player puts noisy energy into the musical instrument. For pianos it is the ‘whack’ of a felt-covered hammer—or the ‘whack’ of the metal clapper in bells. Brass players are actually doing ‘raspberries’ into their mouthpieces: form your lips like you’re going to say ‘p’ and blow—that ‘raspberry’ sound is what is going into the instrument. And then the trumpet/trombone/tuba does its magic: it absorbs/suppresses all the non-musical noise, and only the musical sound emerges. Same with bells—the bell absorbs/suppresses all the non-musical sound in the ‘whack’, and only the lovely bell sound emerges.
Ugliness in, Beauty out.
I suppose that’s a little like Passion Week: the Ugliness of hatred, of the fickle mob, of betrayal, of cowardice, of the Sins of the World, of Death—all of that goes in, and on Easter morning out comes Love.