Klarinet Archive - Posting 000657.txt from 1999/11

From: PyneClarion@-----.com
Subj: [kl] Irregular Mouthpieces
Date: Tue, 16 Nov 1999 21:12:04 -0500

Michael,

Airflow is limited by the reed-valve action at the mouthpiece in a way
similar to a 2 cycle gas engine controlled by a reed-valve rather than a
rotary-valve.

If you blow the mouthpiece and reed alone the resistance you experience will
not be a great deal less than when attached to the complete instrument.

In the case of the clarinet the fundamental cycle of the reed-valve is at the
frequency of the tone that is being produced. The architecture of a large
(relatively) bore instrument like the clarinet does not offer a great deal of
resistance to flow beyond the reed mouthpiece interface. It is more
importantly involved with the behavior of the standing waves.

Interestingly, barrels with rectangular bore shape have been commercially
produced that play very similarly to round bore barrels. And of course there
are the Selmer sax mouthpieces...

Best,

---James Pyne
Pyne/Clarion, Inc.
http://www.pyne-clarion.com
1-800-JPYNE-440

>Thank you for your response. I hope you will indulge me in what may seem
>like a dumb, though related, question.
>In a former working life I got to see a lot of the innards of aircraft jet
>engines, and was fascinated by the design concern for optimal air/gasflow (I
>am not an engineer).
>Although the analogy may not be a good one, I am similarly interested in the
>efficiency of the airflow in clarinet playing, given its importance to the
>resultant sound. Much has been said on this list and elsewhere about the
>significance of the oral cavity, sinuses, instrument bore and the like, all
>focussed in the main on minimising the impedence of the airflow, save of
>course for the reed's resistant role. Yet smack bang in the middle of this
>airflow channel of curved surfaces from lungs to clarinet bell, there is a
>decidedly angular throat in an otherwise smoothly shaped mouthpiece. To cap
>it off, some manufacturers take pride in making more acute, the angle of the
>walls of the throat, which seems even less consistent with an assumed desire
>for smooth flow and roundedness of sound.
>There is clearly something fundamental missing in my understanding, so I
>would appreciate an explanation from you, or indeed anyone else, who could
>shed light on this for me.
>TIA,
>Michael

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