 The Clarinet BBoard
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Author: Caleb
Date: 2012-09-30 06:34
I find this when I adjust the register key of my clarinet this afternoon.
First, disassemble the register key.
Second, press the "A" Key and play, you will hear the Bb note. And you can feel the air come out from the register key hole rapidly.
Third, press the "A" Key and play the overtone by adjust your embouchure, you will hear a concert D or D#, but now you can feel a little or nought air come out from the register key hole. And the air speed is very slow.
Can anyone tell me why this happen?
Thanks.
Later, I found that you may test this effect in a simple way.
First,set up the clarinet without lower joint and bell.
Second, play the middle C and you can feel the air at the end of upper joint by the right hand.
Third, play the G3 without push the register key, this thime the air speed is much slower.
Post Edited (2012-09-30 09:01)
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Author: JHowell
Date: 2012-09-30 16:51
Think of the vibrating column of air like any other vibrating thing -- a string, for instance. If you pluck a guitar string, the point at which its excursion will be greatest is at its center. However, if you pluck the string while lightly touching it at exactly the center, you will get a tone that is one octave higher, corresponding to half the string's length. The string's point of greatest excursion will no longer be its center, but will be the center of each half of the string. The center itself, where you touched the string to create the harmonic, will be almost still.
Now think of the register tube as a dividing point in the air stream selecting a harmonic. This is a different function than when it is defining the length of the tube, which it does when playing a throat B flat.
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Author: Caleb
Date: 2012-10-01 00:05
Dear JHowell
Thanks, your idea is useful. I understand the theory of playing a harmonic on a string, but how is it done by I just change my mouth? I mean, nothing been change except my mouth and my mouth is at the begin of the air stream, not the middle.
Thanks.
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Author: JHowell
Date: 2012-10-01 04:27
Not all harmonics are in the middle of things, or are selected like a string's harmonics. A number of harmonics are present in the sound you play in the lower register, just weaker, just as the higher harmonics are present in the vibration of the string also. With your embouchure or airstream you select the higher harmonic and the tone hole changes its function. The node is now higher up the tube than the tone hole.
The overtones are a little different on the throat tones than the rest of the instrument -- when I overblow a throat B flat I get an E natural.
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Author: kdk
Date: 2012-10-01 13:01
I don't know enough about the acoustics to offer anything specific, but when you "just change [your] mouth" can't you also be influencing the mode in which the reed is vibrating? I don't really completely understand the relationship between reed vibration and the vibration on the air column, but it seems to be a two-way relationship - each can influence the other. This is, of course, not what's going on when you open the register vent to produce upper partials, though it may have something to do with whether or not those partials are i tune.
BTW, is that high E you get from overblowing Bb (I get the same thing and occasionally use it) really a flat F, which is in the series above Bb? It seems as if the altissimo register tends to produce overtone pitches that are flat. For another example, shouldn't the available series above the fundamental fingering for C4 be G5-E6-*Bb6*? But that's the standard fingering for A6 , not Bb.
Karl
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