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Klarinet Archive - Posting 000508.txt from 1997/09

From: Roger Garrett <rgarrett@-----.edu>
Subj: Re: Clarinet material
Date: Wed, 10 Sep 1997 11:52:21 -0400

I suggest that Jonathan contact the makers of Bach and Yamaha and tell
them that the thickness of the wall has nothing to do with the air column
vibrations which are caused by the lips vibrating. Their research shows
that the materials have everything to do with it. Professional brass
players remove laquer from their horns all the time....that is considered
a material. The concept that the material has nothing to do with the way
vibrations occur is absurd! Beyond that, if you want to get technical, if
the wall itself is not vibrating, the material still contributes to the
way the air column is excited. This is precisely why Bach and Yamaha
manufacture horn with varying thicknesses of bell and leadpipe....note..I
did not say bore size, I refer to thickness of the material itself.

Roger Garrett

> NOT TRUE. Wall vibrations do not contribute audibly to the sound of a brass
> instrument. The air column vibrations create the sound in a brass
> instrument. This is TOTALLY different than the sound mechanism on a
> violin, which works as follows:
>
> * bow pulls across string causing string to vibrate
> * string vibrations are transmitted through bridge to the top plate
> of the violin
> * top plate vibrations are transmitted to the back plate by the
> sound post
> * back plate vibrates moving a large mass of air and creating most
> of the sound
>
> On a brass instrument, the libs vibrate and excite the air column to
> vibrate. That's why these are also called "lip-reed" instruments.
>
>
> ><<
> >Perhaps it's not the tone (darkness...sorry Dan) that the
> > material affects but the projection of sound. Can softer materials absorb
> > sound more than harder materials?
> >>>
> >Yessiree. If the material is really soft it will affect the sound.
>
> Certainly, if the material is too soft, you won't even be able to make an
> instrument out of it. But any reasonably hard material such as wood, metal
> or plastic will work. FYI, the difference in thermal absorption between
> copper, brass, silver and wood is very small. Between the metals there is
> only a difference of at most .06 percent. Between the metals and wood
> there is a difference of just over 2 percent.
>
> Note that wood absorbs 2 percent less thermal energy than metal does.
> However, because of losses due to porosity the combined losses of
> thermal/porosity effects is slightly greater in wood than in metal. For a
> highly polished, smooth dense wood, the difference from metal is in the 2
> percent range, putting it just on the edge of detectability by the player
> (not by the listener).
>
> There are also viscous losses due the flow of the air through the tube.
> Even if the surfaces are perfectly smooth, there will still be viscous
> losses due, in essence to the air rubbing against itself and the smooth
> walls.
>
> Bottom line, once again, the material doesn make any difference in real life.
>
> >
> ><<
> >I always thought this was so. Part of
> > "setting up" a clarinet is polishing the bore; does this affect the
> > sound/timbre of the instrument? Again, I thought this was so. Please
> > explain.
> > >>
> >Can't explain... Don't know enough! But I do know that some say the clarinet
> >to buy is the one with a porous looking interior (see paper by Hite I believe
> >at his web site on barrels).
> >
> >I do think that the level of polish on all commercially made professional
> >instruments is sufficiently high enough to produce the same effect though. If
> >there is such an effect, I would guess it would be affecting the way in which
> >standing waves are reflected inside the bore. Much in the same way as frased
> >holes affect the timbre of an instrument.
> >
>
> As I've mentioned in previous posts, having smooth surfaces and rounded
> corners (which you refer to as fraised holes) is VERY important and has a
> MAJOR effect on the playing character of a wind instrument. This is due to
> turbulence caused by rough or jagged surfaces. But again, this is
> independent of material.
>
>
>
>
> --------------------------
> Jonathan Cohler
> cohler@-----.net
>
>
>

   
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