Klarinet Archive - Posting 001017.txt from 2003/03
From: Elgenubi@-----.com
Subj: [kl] Cones vs Cylinders
Date: Mon, 24 Mar 2003 20:07:38 -0500
List,
I apologize for sending a previous post three (!) times. Thanks, Bill, for
pointing out correctly what I did wrong.
Tony wrote:
<<<<<(Quoting Me from an earlier post) "Conclusion: This supports the
dilemma Dan Leeson has pointed out."
What dilemma is this?
Lots of arbitrary but normal clarinet setups don't immediately produce
the fundamental either. Beginning students often can't do it
straightaway even with a normal mouthpiece. They need to be guided
towards an appropriate reed, and further towards an appropriate
embouchure.
Given this, is it then surprising that other aspects of your 'strange'
setup don't accord with what a 'clarinet' is predicted to do?
Nobody would want to claim that theoretical analysis can explain the
sounds that are produced by even simple 'strange' setups. The
mathematics involved is just too complex. It can't even predict
accurately what sounds a beginner will produce.
But it's perverse to challenge an analysis that correctly predicts what
will happen to a simple stable setup -- a 'clarinet' -- just because it
doesn't apply to one of those strange setups. You can understand why a
'clarinet' will overblow at the twelfth, because the argument involves
assumptions about the boundary conditions which can be seen to be
realistic for a 'clarinet', but not realistic for a 'strange' setup.
And actually, those strange setups aren't interesting musically, which
is why I don't really want to bother with them. For me, it's enough to
want to understand more fully something of what *is* interesting
musically, even if my understanding of all sorts of other more
complicated things is necessarily highly limited.>>>>>>>>
Yes, I agree. I've learned something here. The 'dilemma' I referred to was
that basic theory says that a cylinder, closed on one end, overblows to the
12th (3rd harmonic), yet Dan referred to a simple experiment that seemed to
contradict that. I've proven to myself that this was not a 'simple'
experiment, but a complex one. My bassoon reed shoved in a clarinet seemed
to have characteristics of both cylindrical and conical pipes. The missing
fundamental doesn't bother me so much now, for some of the reasons Tony
mentions. I've learned, or rather remembered, that engineering often is
finding and then refining the stable, understandable solutions to problems,
and just plain avoiding the situations that seem too complicated and weird to
understand. Sax and Sarrusa and Heckel and Buffet and all the rest, I'm
sure, were doing all these same experiments, much more thoughtfully than I.
The instruments they left us are the ones that worked best. I guess I got
involved in this partly because I love that the clarinet is a work of
engineering and art from so long ago.
I will now go read some of the references mentioned. I will pay par
ticular attention to 'impedance' and 'coupling' issues, things I should know
more about (my day job is electronics). I want to understand better the
quote of Joe Lande, provided by Mark:
<<<<Roughly, the reed can play at its own resonance (loaded a little by
whatever is on either side of it). This is a squeak. However, if it is
damped (lips on it) and if there is a sufficiently strong resonance at a
lower frequency, it can be driven (nearly) at the frequency of that
resonance. It's actually rather difficult to answers to
- how strong must the resonance be
- how near must the resonance be
We're currently working on this and I shall put more up on the web later.
The impedance of a big diameter tube is low, and so its impedance at
resonance may not be enough to drive the reed. Similarly, when you open a
register key and weaken the low resonance, the reed jumps to a higher,
unweakened resonance.>>>>>>>
Jim Lande's suggestion to see the effect of a dowel in the clarinet
(decreasing the volume of the tube and increasing the impedance???) I will
save until I understand better.
This is an interesting discussion!!
Wayne Thompson
PS I have played Krumhorns. Great instruments. Bill's references say the
important thing. They would presumedly overblow the 12th if they could, but
because the player does not usually touch the reed, embouchure can't be used
to facilitate overblowing. In fact I would now assume that the reed is
optimized for the one register that is played. And anyone out there who
hasn't heard Racketts and Krumhorns in consort, go find some and have a
treat.
---------------------------------------------------------------------
