Thanks to all who participated in this thought provoking exercise. At last count, we had approximately fifty entries, and over 2,000 downloads concerning this question. Some of your answers were very close and some were way off. I have listed two who will be receiving “free” arrangements of their choice as well as one contributor who submitted an interesting question which may be addressed at a later date.
We had one reader “nail” the correct answer and one who was so far above me, I wasn’t sure if he was correct or not, so we are giving one arrangement of their choice to each for their answer.
“Names have been withheld to protect the innocent”.
Here is an interesting observation-
I have no answer, but a few questions.
First, did anyone else notice at the moment the bell hit the water, the pitch actually dropped about a half-step, before it raised a half-step from the original pitch? Why?
Second, try this: blow air (no buzz) through the mouthpiece into an open horn and listen to the pitch. Next, lightly tap the palm of your hand on the mouthpiece (with no valves down) and listen to the pitch. They are different. Why?
Included below are the two winning entries-
Best Answer and Co-Winner
All I can say is [and this is probably one of the worst “theories” I have ever written, so I won’t post it on The Trumpet Blog]:
I tried the same experiment. However, I think an “air pocket” is present somewhere within the bell, because:
If I started the trumpet at the bottom of the sink, the “air” that was in the bell comes out through the mouthpiece as I push the horn down
[note that I put the horn in the water without my lips already on the mouthpiece]
and the horn is extremely sharp when I first begin playing, since the tubing length was shortened because of the water.
However, after a few seconds of playing, the horn gets flatter, since my playing/”air”/CO2 had expelled the water that had been filling the bell up to a certain point.
Then the note I am playing stays consistently “in tune” when the horn is in the water, due to an “air pocket” or “buffer region genf20 hgh pills” somewhere in the bell.
So maybe it still has to do with shortening of the tube length? Or does that have to do with the “resonant space” in front of the bell [i. e. a horn gets sharper if you put the bell against a wall]?
Okay, I think I confused myself
I’m afraid I may not have explained this well [I have a habit of such], but feel free to ask if you have questions [other than “CDF, how could you come up with such a bad theory?”]
I’ll probably be able to clear this up once someone [who isn’t a quack scientist like me] posts their thoughts
“Notice how your tone sort of breaks up as the pitch changes? That’s because the pitch is actually at the next harmonic flattened to a half-step above the original note. (See http://www.public.asu.edu/~jqerics/ess_play.htm.)”
The phenomena addressed in the second question is due to the manner in which energy is added to the acoustic system. When you blow air (no buzz) through the horn the system reaches critical damping (I think that’s what it’s called — I don’t want to say how long ago college was but Ronald Reagan was president) and the principal resonations occur at the fundamental frequency. When you “smack” the mouthpiece you excite the acoustic system with a multitude of high frequencies for a very short time. Resonations occur at many higher harmonics and decay rapidly, causing you to hear a higher pitched “pop.”
Putting the bell in the water changes the resonance equation from that of an open tube (f=(nv/(2(L+0.8d))), all positive integer harmonics) to that of a closed tube (f=(nv/(4(L+0.4d))), positive odd harmonics only). And no, I couldn’t just remember those equations from college, but they weren’t hard to find (http://en.wikipedia.org/wiki/Acoustic_resonance). As the air you’re blowing through the horn bubbles out (thereby venting the closed tube), the water level inside the bell stays constant, so the “L” in the equation doesn’t change.
Notice how your tone sortof breaks up as the pitch changes? That’s because the pitch is actually at the next harmonic flattened to a half-step above the original note. (See http://www.public.asu.edu/~jqerics/ess_play.htm.)
The water acts as a *stop* mute
Thank you who participated and keep watching for more questions about trumpet related issues.