N i g e l wrote:Im not convinced by that ball moving demonstration. I think the difference in force & ball movement is due to the shape of the air current source. The straw concentrates the flow and gives a high force onto the ball, the bell of the trumpet/trombone spreads out the air flow over a wider area giving less pressure on the ball.
Is it similar to a garden hose with a jet attachment for blasting dirt versus a sprinkler attachment for gently distributing the water; same amount of water but different flow concentration.
Indeed, in the video at 1:58, he plays the mouthpiece alone. The air comes out of the stem of the mouthpiece and moves the ball. So clearly there is air going into the horn that also comes out of the bell (and thus has virus in it too). It has been diffused by the horn though so very little hits the ball.
So you need a cover over the bell of the horn to act as a mask, but also around the mouthpiece as well.
My concern is muso to muso. We are outside and the audience would be far away. How much virus builds up on the bandstand for all the band to inhale?!