What happens when blowing a horn..?

Question

( I asked this in music but got 0 responses )

http://en.wikipedia.org/wiki/Blowing_horn

Say I have two horns, as above, and one of them is much smaller than the one in the link and the other is much larger.

If I blow both horns with the same amount of force will one of them be louder than the other, will they both sound the same or will the larger one be quieter because I'm not blowing hard enough..?

The reason I'm asking is I was stood having a cig outside and exhaled with my lips sort of closed and it made a sound, obviously, but then I thought about putting a horn to my lips and how it would make a much louder sound than a little "Pffffffffffffft!" without a horn... This, as you might have guessed, led me to wondering about volume and horn size/shape.

Before you ask... Yes... I am very bored today.

Any links/references would be greatly appreciated

Answer 1

I would expect that the larger horn would have a lower pitch.

The volume, or more precisely the power of the wave exiting, will be precisely equal to the power input, according to the law of conservation of energy. That being said, a resonating pipe builds up a standing wave which can effectively amplify the signal by adding successive waves, but that requires a specific ratio of width to length.