Klarinet Archive - Posting 000113.txt from 2010/08

From: Jennifer Jones <helen.jennifer@-----.com>
Subj: Re: [kl] speaker bushes
Date: Sat, 14 Aug 2010 15:24:48 -0400

On Fri, Aug 13, 2010 at 12:51 AM, Nitai Levi <clarnibass@-----.com> wrote:

[snip]

> The hex shape on the outer part of some register tubes is so it's easier to
> remove. There's a flat part to hold, or if the tube is threaded, you can even
> use a hex key (actually the opposite of a key, with the hollow side, don't know
> the name in English).

I would think it would be a socket wrench, except that the bushing on
my clarinet is so low sunk that it would require a very fine socket
wrench.

>>> From this and experience with my own clarinet, I am guessing
>>> that "speaker bush" refers to the metal reinforcement around the
>>> hole for the register key
>
> It's not a reinforcement, it's the hole in the metal tube itself that is the
> register hole. The hole in the body is just a "holder" for this.

I think I just realized an important function of the register tube and
thumb bushing and why they stick so far into the bore of the clarinet.
They are right in line with the track condensation takes to drain out
of the clarinet. Sticking into the clarinet "raises" the register
hole off of the surface of the inner bore so that water does not get
into them. I notice all the other tone hole chimneys are flush with
the inner bore.

[snip]

> By the way re undercutting tone holes mentioned in the article, recently there
> an article in an oboe journal about this and other effects. It was summarised
> and posted (in his own words) by an oboe specialist. I will ask if he minds
> posting it here too.

That would be really cool ! :-)

>> Does this diagram describe just the effect of the speaker hole
>> position, a combined effect of the bore diameter and speaker hole
>> position, or does it simply approximate the variation in width of
>> 12ths along the range of the clarinet.

>You're right that the article could be clearer. The diagram shows just the
>effect of the register hole on tuning of the second register. It isn't
>completely clear.

The caption in bold for the figure on the second page states that the
figure reflects the relationship between the speaker hole and
variation in the second register pitch (1st stays constant). In
addition, the sentence preceding the figure, refers mainly to the text
description of the effect of speaker hole position on twelfth width.
Though there is some mention of bore size in the text preceding the
figure, it is not addressed adequately to expect that to be reflected
in the figure, on the basis of that sentence (it is only mentioned to
tell us the difference between wide and narrow bore instruments; the
effects of variation in bore diameter are addressed below the figure
and therefore that sentence does not refer to them). Finally, the
figure shows us variation in the width of the twelfths, but does not
show variation in the position of the speaker key, or bore width.

The difficulty with taking the "The above diagram..." sentence
seriously is that it is difficult to reconcile with the specific bore
diameter twelfth width relationship discussed in the text. There are
a few reasons for this. The text description of the effect of
altering bore width addresses variation in the first register, not the
second (in contrast with what is stated in the bold caption of the
figure). In addition, the lack of specific reference to bore width in
the figure itself leads me to recommend deletion of that sentence,
unless the figure generically reflects the current relation between
twelfth width across the range of the clarinet. In which case, the
bold caption should be rewritten to state something to this effect.

>...but safe to assume they are talking about the effect it has
>on what they mentioned previously i.e. a normal bore size of about 14.5mm-15.3mm
>with close 12ths. But maybe this effect is independed of bore size anyway. They
>don't really give a lot of details about the register tube so you can look more
>into this from other sources if you are interested. A simple way to check is to
>play the long B and then play it again but instead of the register key, press
>the side Bb key (second from top side trill key). This is one example of the
>effect of register hole position, size and length on a note.

I am not arguing that bore size does not affect twelfth width and I am
not arguing that register hole size does not affect twelfth width. I
expect exactly the opposite. What I am looking for is dissection of
the paramaters so that they can be addressed individually. Not that
this is the only way of doing this (Obviously people have been doing
it organically for centuries). I suspect that these cannot all be
addressed in one figure. Addressing the effect of speaker hole
position on twelfth width would require a separate data set for each
speaker hole position, hence the figure would have several lines,
perhaps a minimum of three speaker hole positions would be addressed.

The relationship between each of these speaker hole positions and
twelfth width still may not adequately address these effects, because,
for example, two different speaker hole positions may affect register
intonation such that it is impossible to keep one register
consistently in tune between the different speaker hole positions.
Hence, it is probably necessary to examine the effect of speaker hole
position on each register separately, i.e. speaker hole position
versus chalumeau to throat and speaker hole position versus clarion.
This could be done with three speaker positions, resulting in a figure
with six data traces. A simpler scenario involves drilling one
speaker hole, adjusting the rest of the tone holes to be in tune on
the bottom register, then drilling a second speaker hole. When the
first speaker hole is plugged and the second speaker hole is used, is
the bottom register still in tune? What is the intonation of the top
register like depending upon which speaker hole is used?

The relationship between upper bore diameter and twelfth width would
fit nicely in another figure, while the relationship between lower
bore diameter and twelfth width would fit into a third figure.

I would be surprised if something like this has not already been done.

-Jennifer Jones
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