Klarinet Archive - Posting 000077.txt from 1998/12

From: Grant Green <gdgreen@-----.com>
Subj: Re: [kl] The helionet
Date: Wed, 2 Dec 1998 22:31:23 -0500

>> (1) Does the helium in fact need to be in the mouthpiece, or even the
>> mouth, for the effect to be significant?

I think the speed of sound will change depending on the density of the gas
in the bore, so if you start with all He and begin exhaling CO2 into the
instrument, the pitch will drop. If you want the pitch to stay consistent,
you'll need to fill both the instrument *and* the player with helium.

***
>> (3) Do you need some sort of valve at the clarinet 'end'?
Nope.

>> (4) What would be the most sensitive way of controlling the flow of gas
>> into the system?
Fill the player ;-) Seriously, the bore of a soprano clarinet is probably
only about 10cc, so a player with a lung full of helium could close all the
holes, fill the horn (without sounding a note), and then begin playing.
You'll get some CO2 as well, in a constantly changing ratio, but I suspect
the players won't be playing many long passages. Make sure they're sitting
down ;-)

>> (5) What sort of results might we anticipate from the Heifetz of this
>> instrument?-)
Intense giddiness.

>(1a) Would it be better to put the helium in lower down, since it's less
> dense than the air?
No, unless you're going for uncontrolled and inconsistent squealing, you'll
want a fairly uniform gas throughout the instrument.

>(6) Since helium is expensive, how about CO2?
You're already blowing CO2 into the horn - that's our starting point! OK,
actually you exhale normal air that is somewhat enriched in CO2. CO2 is
denser than normal air (higher molecular weight), so if you ran pure CO2
through the horn you'd lower the pitch. If you were able to exhale SF6 (a
very dense gas, often used in packing tennis balls), you might get down
into the bass range. Note: I don't advocate trying that...

Grant

+++++++++++++++++++++++++++++++++++++++++++++
Grant Green gdgreen@-----.com
http://www.contrabass.com
+++++++++++++++++++++++++++++++++++++++++++++

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

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