Klarinet Archive - Posting 000556.txt from 1997/11

From: Jrykorten@-----.com
Subj: RE: Clarinet Material Makes a difference - proof enclosed.
Date: Fri, 14 Nov 1997 09:41:45 -0500

I'm reposting this cause AOL appears to be swallowing lots of my email to
Klarinet. I think this is important enough...

I have been listening, and reading, about the clarinet acoustic debate going
on here on the list for a while now. Being trained in the sciences, I
immediately took the side of the acoustician's and physicist's position that
the physics of the situation dictate that material should have no effect.

But one must remain a student of observation to be a scientist... So I
decided to do an experiment.

It always seems to me that when theories break down it has to do with
boundary conditions. In fact when the Clarinet bore changes from cylindrical
to the bell, such a boundary condition exists. (That is the physical location
where the bore changes from cylindrical to conical.) The bell is also acting
as an acoustic impedance coupling device. In a transitional geometry such as
this I would expect that the theoretical math describing the acoustics and
the actual situation may differ. In fact, this is where engineers make their
money (and why mathematicians dislike engineers). Engineering involves
observation and making up math to describe an observation. Fudging, of
course, where necessary.

So, I undertook a little experiment to see if material affects the acoustical
performance of the clarinet. And in fact I have some surprising results. This
is something that I hope each of you will try...

Take a piece of playdough (approximately two ounces or a decent fistful).
Plaster the playdough around the outside surface of your bell, just abover
where the metal band around the largest diameter is.

Now play an F major 7th arppeggio (lowest register) and a C major 7th
arppeggio (starting at A440 or A44X what ever). Do some fancy articulation as
well.

Have a woman listen if you are male. They have better ears (even if they
don't buy expensive stereo equipment).

Then while playing these two arppeggios have your observer remove the wad of
playdough.

To me the differences in sound, are plain and simple. The playdough damps a
high frequency component that adds richness and overtones to the sound. It
also sounds this way to my wife and my brother. (I asked them to describe the
difference before I told them what I heard.) The diferences are distinct and
obvious.

Now for the interesting part. Yes the sound is WAY DIFFERENT! But more
interestingly to me the resistance of the right hand in the upper register
(A440 and above) completely changes!!!

What is happening here? The playdough is acting to damp vibrations in the
bell of the clarinet. If the sound of the clarinet changes when the playdough
is on it, then the clarinet must have vibrations that affect its sound.

When I tried moving the playdough up the length of the clarinet, I could
convince myself of some very minute changes in sound, but nothing of the
order of magnitude of change as when the playdough was placed on the bell.

Therefore, the material used to manufacture a clarinet DOES have an influence
on the sound. But this influence is most likely to be felt in the very lowest
(physically far away from your mouth) region of the clarinet.

Now will someone please explain the change in resistance felt while doing
this experiment?

Jerry Korten
NYC