Klarinet Archive - Posting 000649.txt from 1998/07

From: Roger Shilcock <roger.shilcock@-----.uk>
Subj: Re: [kl] The LH Sliver Key and the Physics of Closed Tone Holes
Date: Tue, 21 Jul 1998 04:19:21 -0400

To make the two keys govern the same hole, the first difficulty seems to
be that, to serve as a useful trill, the RH key *has* to act as directly
as possible. This means that the extra mechanism would be associated with
the sliver key (if it could stay a "sliver", which seems unlikely), and
the advantage of using just the left hand might well be nullified.
(IMHO)
Roger Shilcock

On Mon, 20 Jul 1998, Jonathan Cohler wrote:

> Date: Mon, 20 Jul 1998 11:44:25 -0400
> From: Jonathan Cohler <cohler@-----.net>
> Reply-To: klarinet@-----.org
> To: klarinet@-----.org
> Subject: [kl] The LH Sliver Key and the Physics of Closed Tone Holes
>
> The LH Sliver Key
> -----------------
>
> Keys have been progressively added to the clarinet over time to make
> substantial improvements in the ease of playing. One could argue that many
> of the keys on the instrument are not "necessary", because people played on
> instruments with many fewer keys back in the days of Mozart and Beethoven.
> Of course, then again, all one has to do is go listen to someone attempting
> to play on those old instruments to realize why the keys have been added.
>
> There is an important reason for the LH sliver key (which has already been
> mentioned, I believe). It allows one to finger chromatic passages entirely
> in the left hand. This is important because one of the major technical
> problems that all human beings encounter is the synchronization of the
> right and left hands.
>
> The right hand is controlled by the left side of the brain, and the left
> hand is controlled by the right side of the brain. When the two hands must
> move in a synchronized fashion, a signal must cross between the two sides
> of the brain. There may be some brain specialists or doctors on the list
> who could elaborate further, but my understanding is that the amount of
> time for this signal to be transmitted is substantial (on the order of 10s
> of miliseconds).
>
> It is precisely because of this signal delay time that any synchronization
> of left and right hands is so difficult. You can demonstrate this to
> yourself by trying the following excercise.
>
> 1. Trill from fourth-line D to fifth-line F. This involves
> the synchronized motion of the second and third fingers
> of the right hand. This is quite easy to do.
>
> 2. Trill from fifth-line F to A one line above the staff. This
> involves the synchronized motion of the first finger of
> the right hand and the third finger of the left hand.
> This is very difficult to do and sustain.
>
> The LH sliver key provides an additional mechanism for eliminating two-hand
> finger synchronization in numerous instances. It also provides some
> critical trill fingerings. I think it would be fair to say that in
> virtually every piece I play that has Eb first line or Bb above the staff,
> there are important uses of this fingering.
>
> Of course, it is possible to work around this fingering using the side
> fingering, but it is clearly much more difficult to do so, and dramatically
> increases the probability of error to do so.
>
>
> The Physics of Closed Tone Holes
> --------------------------------
>
> A tone hole covered at the top definitely has a noticeable effect on the
> instrument. (See "Fundamentals of Musical Acoustics" [Benade, Dover] pp.
> 448-449 for more details)
>
> Imagine a cylindrical tube with tone holes in one section of the tube.
> When these holes are covered on top, the tube behaves acoustically as if
> the section with the holes was slightly longer and slightly larger bore.
> The increase in length obviously lowers the overall pitch, and the local
> change in bore size modifies the relative positioning of tube resonance
> peaks which can dramatically change the playing characteristics of the
> instrument.
>
> The magnitude of the effect is controlled by four parameters:
>
> 1. the bore diameter 2a
> 2. the tone hole spacing 2s
> 3. the tone hole diameter 2b
> 4. the pipe wall thickness t
>
> Both the length of the tube segment and the cross-sectional area of the
> segment are enlarged by a factor E given by:
>
> E = 1 + ((1/2)*(b/a)^2*(t/2s))
>
> According to Benade, "For most woodwinds, the change implied by this
> formula ranges from 2 to 5 percent."
>
> Therefore, if you plug up the LH sliver key hole, you will make a
> noticeable change in the pitch and playing characteristics of the
> instrument. It may be the case that these changes are small enough to deal
> with from the players point of view, but there is no question that a
> high-quality instrument was designed with the hole as part of the overall
> design. In other words, plugging the hole has noticeable effects on more
> than just that one note.
>
> Designing an instrument with one hole shared by the side and sliver keys
> does seem to be a good idea on the surface. This would give the player the
> same sound and intonation for both fingerings, of course.
>
> I am no expert on the mechanical issues involved, however, it must be a
> daunting task or we would probably see more of these mechanisms on the
> market today.
>
>
> ---------------------
> Jonathan Cohler
> cohler@-----.net
>
> --------------------
> Jonathan Cohler
> cohler@-----.net
>
>
>
> -------------------------------------------------------------------------
>
>

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