Klarinet Archive - Posting 000153.txt from 1997/03

From: James Pyne <jpyne@-----.EDU>
Subj: Clarinet bores (was: barrels)
Date: Tue, 4 Mar 1997 16:44:22 -0500

This is in response to a number of interesting entries by Cohler, Karius,
Krelove and others.
------------------------------------------
>At 01:50 AM 3/3/97 EST, you wrote:
>>This is correct. Have you ever noticed that your A clarinet is more
>>resistant than your Bb? This is, no doubt, a result of the smaller bore.
>
> I've often wondered about this. I have always theorized, with no
>scientific evidence to cite at all, that the reason an A Clarinet is
>normally made with a smaller bore was to avoid having to lengthen the
>instrument body (and therefore the tone hole/finger spacings) any more than
>necessary. The reason for this would presumably be a less drastic change
>for the player's fingers when switching instruments. If an A clarinet were
>made longer with a correspondingly larger bore diameter so that the pitch
>of the instrument were still correct, would the resulting instrument play
>more freely than most modern A clarinets do? Or would the additional
>resistance over what we get from a normal Bb clarinet still be there, now
>because of greater air volume that needs to be moved?
> I guess the ultimate direction of this question is to ask whether for the
>price of a little more hand stretch (or maybe some additional mechanical
>linkages to reach where my fingers wouldn't) I could in theory end up with
>an A clarinet that doesn't fight back as hard as most do? Have there been
>experiments in this direction?
-------------------------------------------------------

There may be some other variables at work here, such as efficiency related
to the type and size of the generation device. This would include the part
of the mouthpiece upstream from the end of its bore (really an extension of
the clarinet bore) to the end of the mouthpiece beak. This slot is often
called the windway or tone chamber, and interacts dynamically with a given
reed size and contour (profile). I have previously described a
tube/instrument that I constructed to experimentally evaluate the pitch
drop associated with decreasing bore size relative to length. That
instrument is one half inch longer than my Buffet R-13. They compare as
below:

A. Buffet R-13, cylindrical bore @-----.575, with the normal small expansion at
inlet and large expansion at outlet (Bb clarinet mouthpiece and reed).

B. Tube/instrument, cylindrical bore @-----.500, no modifications to bore
shape.
(Eb soprano clarinet mouthpiece and reed)

The closed tube (all tone-holes covered) Buffet R-13 produces, of course, a
clarinet-pitch low E3 while the tube/instrument produces a somewhat flat
clarinet-pitch low D3. This is more than a whole step pitch drop in an
instrument that is 1/2 inch shorter!

Amazingly the smaller bore tube/instrument easily produces a very loud and
stable sound, rich in harmonic content. In my experience blowing resistance
and loudness do not always parallel each other in as predictable a way as
one would hope. Partly this is because, from a perceptual standpoint,
loudness and sound pressure level are not the same. As Diane Karius
indicates the changes in blowing resistance should be easy to accommodate:

"Increasing the length of the tube doesn't have nearly that great of an
effect - doubling the length of the tube will only double the
resistance to
airflow - well within the range of the human respiratory musculature
assuming a normal person"

Intuitively one would expect stuffy resistance from the small-bore
tube/instrument that I constructed, but that is clearly not the case. It
produces a robust and very clear tone with, seemingly, little effort.
Possibly the return (feedback) we get, especially in terms of richness of
tone quality, is somewhat related to perceived, as well as real effort.

---James Pyne

James Pyne
Clarinet Studio/Research Group
School of Music
The Ohio State University
1866 College Road
Columbus, Ohio 43210
pyne.1@-----.edu
Tel: 614 292 8969
Fax: 614 292 1102