| > supposed to happen here. If you push a larger volume of air though, then
> aren't you speeding up the air flow?
Not necessarily. You shouldn't confuse air volume with speed. You can
push more air through your horn but not have it go any faster simply by
increasing the aperture size. By contrast, you can push the air through
faster without necessarily increasing the amount (volume) of air. The best
example I can give is a reverse example. We've all played with a water
hose at some point in time in our lives. When you really wanted to squirt
someone you'd put your thumb over the opening and really get some distance
on it, right? And all without having to go back to the spigot and turn the
water on even more. The same principle holds true here. If you push the
same amount of air through your horn but decrease the size of your aperture,
you're increasing the speed of the air flow but not the volume. The end
result is being able to play a higher pitched note.
If you keep the aperture the same size but increase the amount of air
(volume) you get the same end result, a faster air stream resulting in a
higher note.
If you increase the amount of air (volume) and increase the aperture
(thereby reducing resistance) you get a louder sound of the same note. If
you decrease the amount of air (volume) but keep the aperture the same you
drop in pitch.
__________________
Dave Bacon |