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Klarinet Archive - Posting 000264.txt from 1997/09

From: Roger Garrett <rgarrett@-----.edu>
Subj: Re: ending the GreenLine plastic/composite thread
Date: Sat, 6 Sep 1997 14:49:58 -0400

These are extremely old references - and I view them as possibly
unreliable sources. Is anyone playing on a plastic flute or organ with
plasic pipes? Is there a difference between plastic recorders and wood
recorders? What about wood flutes and plastic flutes (such as the modern
baroque flutes)? I am also curious who did the listening - were they
specialists on those instruments or laymen who work with plastics, woods,
and metals? Is there a more recent study with more reliable, up-to-date
measurement devices? What about any that are done with the composite
plastics in question?

The only true way to know if a BuffetGreenline and an identical Buffet plastic
(non-composite plastic) sound differently is to compare them side by
side...but of course, we all know that even two "identical" R-13's don't
always sound identical - so it comes back down to opinion - and who is
playing on them and is not.

*sigh*

Roger Garrett

On Sat, 6 Sep 1997, Mark Charette wrote:

> Excerpted from an excellent article at
> http://www.windworld.com/wq/12/dessy-12.htm
>
> Response to Readers Questions on
> Wood, Oil and Water
> by Raymond and Lee Dessy
>
> (C) Copyright 1996 | ISSN 1070-2512 | The Woodwind Quarterly -- for
> author.
>
> ...
>
> It is worth outlining just some of Backus' and Coltman's work on
> pipes, clarinets, and flutes, and include more recent work on
> fipple flutes. Backus' basic premise is that people feel some type
> of vibration at the outer bore wall, and then conclude that this
> affects the vibrating air column. His data clearly contradict this
> belief. Backus comments: "...these arguments probably started in
> early Stone-Age musical circles with assertions that a flute made
> of a human thigh bone had a better tone than one fashioned from
> the rib of a saber-tooth tiger."
>
> Wooden vs. plastic clarinets, silver vs. gold transverse flutes,
> and a large variety of metal, wood, and even paper organ pipes
> have been examined for evidence of an affect of wall composition
> on sound timbre. The construction materials studied span a range
> in Young's modulus of 10**5 (a measure of stress vs. strain
> response). Backus reports, "In no case is there a body vibration
> large enough to give a sound level that could be a perceptible
> component of the normal sound." The air column vibration sound
> pressure levels (SPL) for either silver or gold flutes with wall
> thicknesses of 300 micron (12.5 mil) are 60 dB above any from
> wall vibrations. (The dB scale is not linear, but logarithmic.
> For reference, the threshold of hearing is 0 dB; the threshold
> of hearing pain is 120 dB; an office ~60 dB. The dB scale is the
> log of the ratio of two sound measurements, matches how our ear
> hears, and allows many different measurements to be easily
> compared. 60 dB SPL is a ratio of 1000/1.)
>
> What would the instrument body have to be doing to affect sound?
> Backus concludes that "In order for the body sound to be a
> prominent component it would be necessary to have body
> acceleration levels on the surface of the order of 120 dB*."
> Nominal coin silver or gold flute body acceleration levels are
> only 60 dB. The body acceleration levels in the fipple flutes
> studied lie at or below those of metal transverse flutes, and far
> below that required to affect tonal quality. (*Note the switch from
> measurement of acoustic pressure to body acceleration levels.)
>
> Organ pipes experiments have been performed in which the sounding
> tube was surrounded by a water jacket that was filled and emptied
> of water during performance. "No changes ... could be observed for
> any harmonic when the water was allowed to run out, nor could any
> change in the sound be heard." If significant wall vibrations were
> present they would have been damped out, affecting the perceived
> tone.
>
> ...
>
> "Effect of Wall Material on the Steady-State Tone Quality of
> Woodwind Instruments", J. Backus, J. Acoust. Soc. Amer., 36,
> 1881 (1964)
>
> "Wall Vibrations in Flue Organ Pipes and Their Effect on Tone",
> J. Backus, and T. Hundley, J. Acoust. Soc. Amer., 39, 936 (1966)
>
> "Effect of Material on Flute Tone Quality", J.W. Coltman, J.
> Acoust. Soc. Amer., 49, 520 (1971)
>
> --
> Mark Charette "How can you be in two places at once
> charette@-----.com when you're not anywhere at all?"
> http://sneezy.mika.com/clarinet - Firesign Theater
>

   
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