Klarinet Archive - Posting 000115.txt from 1999/12

From: "Dee D. Hays" <deehays@-----.com>
Subj: Re: [kl] cylinders & cones
Date: Sat, 4 Dec 1999 20:38:49 -0500

----- Original Message -----
From: Neil Leupold <leupold_1@-----.com>
Subject: Re: [kl] cylinders & cones

>
> Given this statement, I'm looking for an admission that the
> conditions under which an instrument is considered cylindrical
> vs. conical do not adhere to the literal definitions of these
> geometric shapes. I've not studied clarinet acoustics to any
> degree, so this is all curiosity. Definitionally, does a cyl-
> inder not retain the same diameter across its entire length
> (I'll confine this definition to circular cylinders)? If this
> is true, then I assume that some authoritative body decided at
> some point in time to instate an arbitrary standard of flare
> percentage to a "cyliner", such that it need not adhere per-
> fectly to the defined properties of a cylinder, but could
> still be referred to as one. Is that right? If not, then
> what event or concept explains the classification of a clar-
> inet as a cylinder when, the bell notwithstanding, it clearly
> is not? Equally as important, is there a codified number to
> indicate the exact flare percentage, past which a pipe 'gradu-
> ates' (pun intended) from a "cylinder" to a "cone"?

Well I don't know if this has been codified or not. However you can take
some of the older clarinets (especially old Alberts) and put the upper joint
on upside down as the diameter in the upper joint doesn't vary to any
significant degree.

Of course the strict mathematical definition is that a cylinder is the same
diameter throughout its length (no ifs, ands, or buts). But acoustically,
some variance can occur before the sound waves "switch over" from the
characteristics of the closed cylinder to the closed cone. By taking
advantage of this, clarinet makers can provide us with instruments that have
better tuning and pleasanter tone quality than could be achieved by sticking
to a strict cylinder.

For musicians and instrument designers, the important element isn't whether
its a true cylinder but what does it act like acoustically.

I even saw an exercise in a book that shows you how to take a piece of PVC
plumbing pipe (and this has a constant diameter) and make a primitive
clarinet.

Dee Hays
Canton, SD

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