low/ high sounds on a pipe

[mollykins]

this is probably to do with the physics of the sound waves so i thought it was best to put it in science.

At cadets, we use a boatswians call to pipe ceremonial occaisions or announcements ie, the ensign has been raised or lowered, or its time for a break.

this is a picture of one. http://ahoy.tk-jk.net...es/BoatswainsCall.jpg

Because there is no ball or anything inside the bouy, you have to cover your hand over the hole, to make a high sound and don't cover it, for a low sound. However when i do it, its the reverse, it doesn't matter which pipe i use, its the same. but why and how?

[wildwood]

I would guess that you either lower your hand too far and restrict the air flow, or don't bend your fingers the right way for the light call.

[mollykins]

For the call, that should be low, you don't cover the hole at all.

But i can get the sharpness right, its sjut the completly wrong pitch.

[wildwood]

You'll get it eventually, just keep practicing.

[mollykins]

I can get the sharpness but the pitch is wrong and you can't do anything about the pitch, other than raising and lowering your hand, but when i do that, the pipe does the opposite to what it should do!!!!!

[LazyGun]

I was mildly interested in this, did a bit of googling, and came up with this link;

http://www.sccheadqua...20Call%20Handbook.pdf

There appears to be some useful pictures and guide instructions from around page 7 onwards. Have you already seen it Molly?

[mollykins]

If you go to page 12, it says how the raised hand makes a low sound and vice versa, but no mtter which pipe i use, i can't do it that way and noone can do it the way i do.

One of the calls, the carry on should go from low to high, but i have to do the hand movements the other way round, to create the right sound.

So can't anyone explain the physics behind what is happening?