Klarinet Archive - Posting 000581.txt from 2003/09
From: "Keith" <100012.1302@-----.com>
Subj: [kl] Rubber lined barrels et al.
Date: Sat, 20 Sep 2003 17:47:20 -0400
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
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Date: Fri, 19 Sep 2003 09:08:04 -0700
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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