Klarinet Archive - Posting 000635.txt from 2003/09

From: LeonardoFuks <leofuks@-----.br>
Subj: Re: [kl] Rubber lined barrels et al.
Date: Tue, 23 Sep 2003 11:17:45 -0400

Clark Fobes:
You could use silicone rubber for lining the barrels. There is a whole line
of hard silicones that can be easily molded and fitted to the inside of
your barrels. I have worked on the replication of historical clarinet
mouthpieces using such rubbers.

With regard to the effect of material on instrument/component acoustical
behavior, it is a continuously evolving research issue that has not yet
been sufficiently clarified.
Several acousticians, such as Coltman, A. Benade and J. Backus worked on
the subject. However the three of them died or retired in the middle of the
80's, and since then not many researchers have investigated this relevant
but complex topic.
Most of the present work seems to be carried out by instrument industries,
that do not publish their results or methods. On the other hand, these
companies frequently make some superficial and obsolete statements in their
product catalogues.
For instance, Yamaha flute leaflets include a "hierarchy" of metals related
to sounding properties such as the "brilliant and noble sound of pure
silver flutes" and other impressive phrases. In spite of that, no
systematic study seems to have been published demostrating the superiority
of precious materials as compared to regular plated brass.

Fox Co. and Buffet, for instance, have been making oboes, bassoons and
other instruments out of polymers and composite materials, with excelent
results, and no one has published a scientific study comparing them to the
usual woods, some of them very rare and belonging to endangered species.
Several environmental crimes happen in areas where these plants grow, such
as in my country Brazil, and we are probably not far from the time when
these woods will not be available anymore, at least for musical applications.
There is now technology to produce materials that mimic and expand the
properties of natural materials: a whole family of composites, polymers and
smart materials could be employed, even reducing the costs of the
instruments, but it requires work and knowledge.
Therefore, it would be very useful if musicians, acousticians and makers
could colaborate in such research. An example of a company that is hiring
scientists is Selmer, at least in their saxophone department.

>Clark
>
>Re your reference to Benade. It isn't what he said, though a lot of people
>on this list have got the idea that he said the material has no influence on
>the sound. (O. Lee Gibson is, I believe a much lesser authority.)
>
>What he actually said was that the vibration from the walls of the material
>is a negligible proportion of the energy radiated into the room. Therefore,
>what you actually hear comes almost entirely from the vibration of the air
>column not the vibration of the material. He was pointing out that this is
>different from the behaviour of a violin.
>
>BUT he then went on to say that the material does have an influence on the
>vibration of the air column. You hear the air column vibrations, but these
>are different if the material is different. The basic reason is that the
>vibration of the material and that of the air column are coupled (which is
>obvious), so a change in one results in a change in the other. He found two
>root causes of this; one is density, the other is surface finish (which, as
>you say, changes the drag on the air column). And he confirmed these with
>his usual simple and elegant experiments, such as sticking lead tape on
>various parts of a clarinet and noticing the change in sound.
>
>So this is entirely consistent with your observations and I am glad you have
>stated them with such weight of experience.
>
>I also asked Steve Fox recently if he had ever made two essentially
>identical clarinets from different woods. He said that he had, and that the
>differences were very noticable. We haven't had a side-by-side test of
>basset horns yet, but since mine and Dan's are cocobolo, and the next one is
>grenadilla, this would be possible and interesting. Wall thickness in a
>basset or bass is, I think, a greater fraction of the bore than in a
>soprano, so the effect may be less.
>
>Keith Bowen
>
>
>-----------------------------------------
>Date: Fri, 19 Sep 2003 09:08:04 -0700
>To: <klarinet@-----.org>
>From: "CLARK FOBES {USER_LASTNAME}" <reedman@-----.com>
>Subject: Rubber lined barrels et al.
>Message-ID: <03fb01c37ec8$35bbb980$d0e5fea9@CLARKW>
>
>I don't know if any of you remember this, but I made hard rubber lined
>barrels for about two years. My personal barrels are rubber lined.
>
>This is a wonderful idea, the greatest advantage being that the bore is
>impervious to moisture and will not change over time. Also, the principal
>mass of the barrel is still wood. At that time I had a machinist making my
>barrels and he tapered the outside of the insert and the oversized bore of
>the barrel so that we could press fit the core. I then bored out the core
>with my reamers.
>
>Unfortunately, we ran out of the 8' of rubber I had scoured the country to
>find and I have not been able to locate more. Rod rubber stock was a very
>common product for years and used to make various insulating parts.
>
>I have tried Delrin as a substitute, but the sound is much brighter. I
>attribute this to the finish on the surface of the material rather than the
>density.
>
>Back to mass. A great deal has been said and written about material density
>and wall thickness regarding tone production of the clarinet. Benade states
>that the material a clarinet is made from has no influence on the sound and
>I believe (someone correct me here if I am wrong) that he stated that the
>wall thickness would have to be MUCH thinner to have any influence on sound.
>His contention is that the sound of the clarinet is dictated by the bore
>configuration and the tone hole lattice only. O. Lee Gibson makes a similar
>statement in his book on clarinet acoustics.
>
>I will be an iconclast here and say "Gentleman, this theory is not born out
>by my extensive experience in making more than 500 clarinet barrels of
>various materials, thicknesses and shapes."
>
>The mass of the barell DOES influence the vibration and therefore the sound
>as the performer perceives it.
>
>Further, the outside shape of the barrel (distribution of weight over the
>length of the barrel) influences the sound in subtle ways.
>
>The material can determine the finish of the bore and DOES influence the the
>drag on the air column which can change the sound dramatically.
>
>HOWEVER, I do agree that the GREATEST influencing factor in mouthpiece,
>barrel, joint and bell design is interior shape.
>
>Clark W Fobes
>-----------------------------------------
>
>
>
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