 The Clarinet BBoard
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Author: Gordon (NZ)
Date: 2001-12-10 10:04
Something I'd love to try sometime.... playing an instrument after a good breath of helium.
It makes the human voice go uncontrollably up about an octave (because of the low density of the gas, presumably allowing the larynx to vibrate faster). I had fun with that once but didn't think of playing an instrument. It must have the same effect on blowing instruments.
Anybody tried it?
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Author: Don Poulsen
Date: 2001-12-10 13:49
The pitch should be raised because helium is less dense than air and as such sound waves travel faster. With a clarinet, wavelength is determined by the fingering, and so with a given fingering or wavelength and a increased speed of sound, the produced frequency is greater.
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe3.html#c1
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Author: Mark Charette
Date: 2001-12-10 13:52
The pitch goes up - it's true. It sounded like a couple of whole tones, but I didn't have my tuning meter with me when I tried this "experiment" ...
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Author: Don Berger
Date: 2001-12-10 16:08
This "important" ? intrigued me so here goes some physical-chemistry comment. Prob. if I read my physics books, somewhere they would give answers to the relationship between sound velocity [1088 feet per second in most airs we encounter { do you remember counting the seconds between the lightning flash and its thunder? 5 seconds =about 1 mile away!!}] and the density of the medium. Densities are air [dry] 1.293 grams per liter [molecular weight avg. 14.4], sonic velocity given as 331.45 meters/sec : helium [pure] 0.178 [atomic weight 2] vel. 965 m/sec : hydrogen [for those who live dangerously] 0.0899 [mol. wt. 2] vel. 1284 m/sec . "Them's the facts" for our calculating wizards, will it compute?? Don
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Author: JMcAulay
Date: 2001-12-11 02:53
Don't forget, if you are actually breathing the stuff, be sure you have someone with you. It isn't the thing to do while alone. Could spoil your whole afternoon. And Don, average atomic mass of He is a tad over 4. The atomic *number* (Z) is 2.
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Author: Wes
Date: 2001-12-11 07:23
A long time ago, I connected a tank of helium through a hose to the top F hole on my saxophone. It was an interesting effect but the pitch is, of course, quite uncontrollable. Perhaps someone could write a piece for the "helium horn" as I called it. Stranger pieces have been played.
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Author: Gordon (NZ)
Date: 2001-12-11 08:22
Pitch will be uncontrollable because indeterminate amounts of air (diluting the helium) may enter open tone holes at times they are not being used. This would be more significant on flute or sax because of the larger, shallower tone holes.
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Author: Emms
Date: 2001-12-11 08:37
Peter - another experiment for you here. you could try other gasses too, and see which has the darkest sound.
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Author: donald nicholls
Date: 2001-12-11 10:54
you could compare Helium to, say, "forest air" (which apparently makes the tone "darker"!)...
nzdonald
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Author: GBK
Date: 2001-12-11 11:31
Does anyone own the CD: "Robert Marcellus plays Mozart with a helium filled clarinet and electrical tape" ?
I searched Amazon...can't find it...GBK
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Author: Emms
Date: 2001-12-11 13:59
No, but have
'Fantasia on Forest Airs' from Bellini's I Puritani
'Walking in the Forest Air' by Howard Blake
and the jazzy 'Sidewalks of Helium'
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Author: donald nicholls
Date: 2001-12-11 17:27
i feel a bit mean now, the "forest air" thing was a swipe at one an earlier posting from Hiroshi, who i think in the same posting suggested magnetising reeds or something. Actually, if you imagine you are breathing "forest air" some people might relax a bit, and in my case at any rate this makes for an improved tone....
So Marcellus almost certainly didn't record the Mozart Clarinet concerto with Helium, tape on his reed OR breathing forest air, but i'll bet the back of his throat was relaxed (although now i've written that i expect to get an email telling me otherwise)- maybe he was THINKING about forest air, i'll bet he WASNT thinking about Helium!
nzdonald
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Author: Brian Peterson
Date: 2001-12-11 17:35
I can hear it (or rather smell it) now...
Concerto for clarinet with baked bean and (broken) wind
enseble accompaniment.
It has possibilities.
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Author: Don Berger
Date: 2001-12-11 21:26
Back to the light gases! Right you are, JMcA, helium atomic weight is 4, also the avg mol wt of air is 28.8 [+]. Does anyone know what concentration of He is used by divers [to prevent-minimize "bends" due to N2 solution in blood, is it a mix of just O2 and He??] , it seems to move up the voice-pitch at least an octave. Also, there may be a complex relationship between sonic velocity in an "artificial" medium and the pitch it could support. Acoustic experts, ARISE. Don
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Author: Emms
Date: 2001-12-11 22:09
OK, Don. Divers use a mixture of gases. Ideally the pressures of nitrogen and oxygen under water should remain the same as that of the surface, as too much oxygen, or oxygen under pressure causes oxygen poisoning. Helium is added in varying amounts depending on the depth of the dive, to keep the pressure of the other gases constant.
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Author: Arnold the basset hornist
Date: 2001-12-12 08:34
Well, let's do some calculation:
Accoustic speed is (at least approximately) proportional to the squareroot of the quotient preassure divided by density.
20 % O<sub>2</sub> + 80 % N<sub>2</sub>: 2561.76 = d<sub>N</sub>
20 % O<sub>2</sub> + 80 % He: 960,184 = d<sub>He</sub>
c<sub>He</sub> / c<sub>N</sub> = sqrt(d<sub>N</sub> / d<sub>He</sub>) = 1.633
12 * log<sub>2</sub> 1.633 = 8.5 semitones is the expected pitch difference when your're playing in an atmosphere where the 80 % N<sub>2</sub> are replaced by Helium.
Any sugestion for a atmosphere, where your Bb clarinet is pitched to be an A clarinet?
I hope, these formulas will help in this discussion,
Arnold (the basset hornist)
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Author: Pam
Date: 2001-12-13 02:39
And to think that I saw it on Mulberry Street. (Thanks Dr. Suess).
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Author: Don Berger
Date: 2001-12-13 18:12
TKS, Emms, Ah Yes, the concept of "partial pressure", should have thot of it. A VG analysis, Arnold, but I am unsure that sonic pitch is that closely related to the speed of sound in a gas medium. My physics books should say something about it [will read], but I recall the very "squeeky" diver's communications on TV shows, seems to be more than a half-octave. Help! Don
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Author: Peter
Date: 2001-12-14 02:51
One fine day they are going to come and take us all away. You wait and see!
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Author: Gordon (NZ)
Date: 2001-12-14 04:48
And I thought that was gone and forgotten into the past, ha ha!
Thanks Mark. Hehe!
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Author: Peter
Date: 2001-12-17 14:58
I remember when that came out! (Oops. Oh, but I was only merely a child back then! Yeah, that's the ticket!)
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