Originally Posted by rowuk

The velocity of sound and the speed of your air do NOT change with the slide. The LIE of fast air is a myth that will not go away. A horns sound is based on its resonant character, that changes with every single brace applied. The pitch that we produce is a standing wave in the instrument. Very little air is required to maintain the wave once it has been started. We only need enough movement of air to keep the lips moving. Projection is not the air that you inhale bouncing off of the back wall. Sound waves travel (air particles bumping into other particles like dominos), not single air particles. That is why the perfect, fluid dynamic trumpets NEVER worked. Wrong principle!

A great player can inhale about a gallon and a half of air and can play for about a minute with that lung full. That is not a very intense stream of air.