Klarinet Archive - Posting 000745.txt from 1998/12

From: "Mark Charette" <charette@-----.org>
Subj: Re: [kl] Gas flow rate in clarinet
Date: Sun, 20 Dec 1998 12:06:34 -0500

>What about something along the lines of a pitsword (used by ships) that
>would project into the barrel- or is that what you're thinking already?

Anne,
A pit sword on a modern vessel uses the conductivity of seawater to
modify the magnetic flow lines between and electromagnet/receiver pair
(conductivity is read on one sensor and is used to modify the output of
the pair). I was a snipe, remember :^) Wouldn't work on a clarinet.

If the barrel tapers and is _accurately_ measured (no mean feat), then
two small holes could be drilled into the barrel and the pressure
differential measured. However ...

If we're just measuring mass flow (not velocity at a point) then an
artificial embouchure would be the simplest way. Measuring output at the
bell implies only measuring the flow at the lowest notes, and I believe
(using empirical evidence from my own playing - how long I can sustain a
single note) that the flow rate changes for every note at an apparently
equal dB level. Considering that my ears follow an admittedly bad F-M
curve, though - I could be entirely wrong about this in a scientific
sense.

So, if I were to measure flow rate, I'd create a workable artificial
embouchure, get a calibrated microphone, a calibrated frequency
analyzer, and do an integration to find out the composite SPL at some
specified distance from the clarinet (since the sound doesn't emanate
from a point source). I'd then adjust the input flow rate to create a
graph for a SPL vs. flow rate for one note, then go on to the next note,
etc. I'd then have to repeat the entire experiment for some number of
supposedly identical clarinets to get some average. I'm sure I'm missing
a lot more - this was just a quick thought.

Grad student time :^)

----
Mark Charette@-----.org
Webmaster, http://www.sneezy.org/clarinet
All-around good guy and devil-may-care flying fool.
"There can be no freedom without discipline." - Nadia Boulanger

-------------------------------------------------------------------------

   
     Copyright © Woodwind.Org, Inc. All Rights Reserved    Privacy Policy    Contact charette@woodwind.org