 The Clarinet BBoard
|
Author: Roys_toys
Date: 2011-12-08 09:02
I'm sorry if this is a dumb question but could someone please explain :
I read that when we overblow the first time we get 12ths on our fundamentals and only the odd partials “because of the characteristics of a ( virtually) straight tube” instead of those nice octaves that "are characteristic of conical tubes" (eg oboe, sax)
But then no mention of why other woodwinds with (virtually) straight tubes overblow in the octave : the flute family
Of course flutes dont have reeds, but isnt it the vibrating air inside the tube thats important rather than how it was started ?
thanks
|
|
Reply To Message
|
|
Author: tictactux ★2017
Date: 2011-12-08 09:50
A clarinet is a cylindrical tube that is open on one end only. -> 12ths
A flute is a cylindrical tube that is open on both ends. -> octaves
A sax is a conical tube that is open on on one end only. -> octaves
--
Ben
|
|
Reply To Message
|
|
Author: oca
Date: 2011-12-09 00:28
The things I would do for a conical clarinet...
|
|
Reply To Message
|
|
Author: denkii
Date: 2011-12-09 01:40
It looks like a clarinet.... but sounds like a sax hahaha!
|
|
Reply To Message
|
|
Author: DrewSorensenMusic
Date: 2011-12-09 01:55
Hi Roys_Toys, to answer your question, I do believe the clarinet "register" key jumps the instrument a 12th as opposed to the flute and sax "octave" key due to the location at where this key disects the sound wave inside the instrument. If you are familiar with a sound wave, it is a sine wave. Within each sound wave there exists upper partials based upon dividing the length of the wave (which effectively doubling/tripling/etc... the Hz if I'm not mistaken). This expains it a bit better, although I didn't read it all:
http://en.m.wikipedia.org/wiki/Harmonic
Bottom line, the "octave" key should divide the fundamental pitch in half, creating and jump of an octave. The "register" key should divide the fundamental pitch into 3, creating a jump of a 12th. Hope that helps. Good luck.
|
|
Reply To Message
|
|
Author: Mark Charette
Date: 2011-12-09 02:15
DrewSorensenMusic wrote:
> Hi Roys_Toys, to answer your question, I do believe the
> clarinet "register" key jumps the instrument a 12th as opposed
> to the flute and sax "octave" key due to the location at where
> this key disects the sound wave inside the instrument.
Ah, no, that's not the reason. The reason is a bit more complex, having to do with the clarinet being a closed cylinder. http://www.phys.unsw.edu.au/music/clarinet/ is a nice start rather than guessing.
|
|
Reply To Message
|
|
Author: DrewSorensenMusic
Date: 2011-12-09 02:45
Upon further analysis, it appears that you are correct. A cylinder (clarinet) overblows at every other upper partial (1st,3rd,5th,etc...). An open cylinder (flute) as well as a cone (oboe, sax) overblow at every partial.
To defend my position, as per your link, the Register key is located 1/3rd of the way down the tube, accentuating the fact that cylinders only overblow at the odd partials.
I apologize for my mistake
Post Edited (2011-12-09 02:47)
|
|
Reply To Message
|
|
Author: Bob Phillips
Date: 2011-12-09 04:35
Sometimes it is hard to see that the hole in the flute's embouchure plate is the other "open" end of the tube. The other is the open tone hole closest to the embouchure.
Bob Phillips
|
|
Reply To Message
|
|
Author: Buster
Date: 2011-12-09 06:11
Drew,
you wrote: "the Register key is located 1/3rd of the way down the tube, accentuating the fact that cylinders only overblow at the odd partials."
First, closed cylinders over-blow to the odd-harmonics.
You have the other facts correct, sort of, but the correlation incorrectly stated.
The (first) register vent is necessarily located approximately 1/3 down the length of the tube from the anti-pressure node for it to function as a register key. (Actually I should say the tone hole for throat Bb is placed in this position so it may function as a register vent. It is a dual-purpose tone-hole.)
The location does not accentuate anything as such. It does, however, confirm the fact the clarinet functions as a closed cylinder. Were the register vent placed in a differing location it would not serve any purpose. (And don't forget that a register vent is not necessary, but merely a convince.)
Also, it should be known that though the pressure node created by an open register vent is located 1/3 of the way down the cylinder, it is not located 1/3 "of the way down" the wavelength of each differing note- its' position is a compromise. Thankfully it coincides closely enough for 3rd-line B through C above the staff to serve its' purpose: weakening/removing the fundamental from the standing-wave, allowing the 3rd harmonic to sound. (Again, were it located in a differing position this would not occur. Or were it much larger in size, it would cease to be useful.)
For the 5th harmonic we lift the left-hand index finger- a second register vent. The location of this tone-hole is close enough to the necessary position to remove the 3rd harmonic from the standing-wave, and the 5th harmonic sounds. (Though the usage of this register vent is optional as well.)
Jason
Post Edited (2011-12-09 06:39)
|
|
Reply To Message
|
|
Author: Mike Clarinet
Date: 2011-12-09 08:02
Seconding Mark's link to http://www.phys.unsw.edu.au/music/clarinet/. This is an amazing website, which explains a lot about woodwind acoustics. Personally, I find the pages on conical instruments (oboe, sax, bassoon) not too clear, but the flute & clarinet sections are pretty easy to follow. There's a video clip on there somewhere showing what happens if you put a flute headjoint on a clarinet and a clarinet mouthpiece & reed on a flute, which backs up the explanations nicely.
|
|
Reply To Message
|
|
Author: Roys_toys
Date: 2011-12-09 08:08
thanks guys for your help.
Bob is correct in suspecting I had missed " Sometimes it is hard to see that the hole in the flute's embouchure plate is the other "open" end of the tube"
|
|
Reply To Message
|
|
Author: DrewSorensenMusic
Date: 2011-12-09 14:09
Buster,
It is true that the register key is only an approximation of 1/3 of the way along each new cylinder created when you lift a finger on the instrument, but it would be inconvienient to have 16 different register keys along the instrument.
The register does have two finctions, in that when the throught Bb is played it does act as a "normal" key, but the title of this thread is "overblowing", and not "What is the fynction of the register key".
Yes the Register key is only a "convinience" to attain clarity on the clarion register, but to overblow without said key would, for lack of a better way to put it, be quite a nightmare.
As for the 5th harmonic, it is not part of this thread.
I stick by my second post, while I was wrong in my first assumption of the matter, it has been clarified and corrected in the second post.
|
|
Reply To Message
|
|
Author: Buster
Date: 2011-12-09 21:14
For all,
Some food for thought, you can play above C6 while remaining in the 3rd harmonic (or partial if you wish.)
The sound and pitch will progressively suffer as you ascend, but it is never the less possible.
Also, the usage of a register vent is not necessary for this- as the title of the thread is "over-blowing."
It can be accomplished by changes in vocal tract tuning (what "over-blowing" truly is), removing the register vent variable from the equation entirely.
-Jason
Post Edited (2011-12-09 23:17)
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
![[C4]](http://test.woodwind.org/clarinet/BBoard/smileys/c4.gif)
we can sound ![[G5]](http://test.woodwind.org/clarinet/BBoard/smileys/g5.gif)
in the third harmonic, ![[E6]](http://test.woodwind.org/clarinet/BBoard/smileys/e6.gif)
in the 5th harmonic, ![[A6]](http://test.woodwind.org/clarinet/BBoard/smileys/a6.gif)
in the 7th harmonic etc.... with only changes in vocal-tract tuning (or "over-blowing".)