|To subscribe or unsubscribe, email firstname.lastname@example.org|
From: "Gregg Bailey" <email@example.com>
Subject: Conical vs. cylindrical
Date: Wed, 25 Aug 1999 23:53:03 CDT
>The slightly less brief answer is that
>for pipes that are closed at one end (the reed closes one end),
Actually, the reed "closing" the end has absolutely nothing to do with it.
If it did, then saxophones would be affected. Here's what I've gathered
through all of my research throughout the years (even though I'm only 17),
though I'll try not to get TOO detailed. Flue pipes have no moving parts;
these include the flute, panpipes, recorders, pennywhistles, etc. When the
tube is closed at one end with the windway at the other end, the tone has
only odd-numbered harmonics due to the fact that the stopper has created a
node of vibration at the closed end and reflects the vibration back down to
the windway which takes TWICE as long as if it went out the top. By
odd-numbered harmonics, I am referring to the sequential number of the
harmonic in the series. So, the tone has the fundamental, 3rd hamonic, 5th
harmonic, 7th, 9th, etc. This can be demonstrated on a drawbar organ to an
extent. Since the pitch of a tube is inversely proportional to its length,
and the "8'" tone is of unison pitch, then you simply divide 8' by 1, 3, 5,
7, 9, etc. to get the other harmonic pitches. The Hammond organ doesn't
have the 7th or 9th harmonics, but if you draw the
8', 2 2/3' (8/3 = 2 2/3), and 1 3/5' (8/5 = 1 3/5) drawbars out, you hear
what sounds like a clarinet, panflute, etc. This is called a square wave,
although a square wave actually contains ALL odd-numbered harmonics up to
infinity. The only difference is that a true square-wave tone is more reedy
due to the higher harmonics.
Now, still speaking in terms of flue pipes, when you remove the stopper at
the end opposite the windway, the tone "seems" to jump up an octave. For
numerical purposes, this is what happens; however, it's not the real truth.
What truly happens is that the removal of the stopper creates a "loop" or
"antinode", and the EVEN-NUMBERED harmonics are now what speak. See, the
tone still has the same pitch, but the ear doesn't realize this because
there is no fundamental or anything beating to recreate the fundamental.
So, the new tone has the 2nd hamonic, 4th harmonic, 6th, 8th, etc of the
SAME fundamental even though the fundamental is missing. These are in fact
the same as the 1st harmonic, 2nd harmonic, 3rd, 4th, etc. of a tone an
octave higher. In summation, both tones have the same fundamental, just
different harmonic content. But for listening purposes, the new tone is all
harmonics of an octave.
Reed pipes are the ones with moving parts, i.e. the player's lips on a
brass instrument, or the double reed on an oboe, or the single reed on a
clarinet. As far as I know, no one seems to really know why a conical
resonator of a reed pipe corresponds to an open flue pipe of any shape and
why a cylindrical resonator of a reed pipe corresponds to a stopped flue
pipe of any shape. However, it is supposed that due to the conicality of a
reed pipe resonator, no real reflection takes place, thus the fundamental is
twice the frequency than if it were reflected back down like in a clarinet.
I don't fully understand this; concepts regarding reed pipes confuse the
heck out of me! I understand flue pipes but not reed pipes. However,
Grant, I don't understand why you say that the reed stopping the end has
anything to do with it, considering that conical resonators contradict it.
Also, the reed only acts as a stopper at one infinitesimal point per cycle.
What did Sir James Jeans do for a living? Who would be his equivalent
today?? There's bound to be SOMEONE by now who fully understands behavior
of reed pipes. But my recent edition of the Oxford Companion to Musical
Instruments says that no one really fully understands.
I hope that I was of some interesting enlightenment to some people on the
list, and I hope we can have a little bit of discussion about this topic.
Get Free Email and Do More On The Web. Visit http://www.msn.com
From: "BROCK IMISON" <firstname.lastname@example.org>
Subject: Baroque Fag fingerings
Date: Thu, 26 Aug 1999 00:03:41 PDT
I've been playing the baroque bassoon for about 2 years, all is well except
I can't find a fingering for top A. I know there's a good one out there
somewhere, you only have to listen to someone like Danny Bond for proof. The
only fingering that works for me requires putting your teeth on the reed,
which is impossible to use in the context of a piece. I'm working on some of
the Corrette sonatas, it would be a shame to leave the A's out or play down
an octave. Thanks for any help.
Get Your Private, Free Email at http://www.hotmail.com
Date: Thu, 26 Aug 1999 06:45:34 -0400
From: Robert Howe <email@example.com>
Subject: Re: Conical vs. cylindrical
Gregg: You have obvious intelligence, but you ought to read a text book
of musical acoustics. Try Nederveen (Acoustical Aspects of Woodwind
Instruments), Benade (Fundamentals of Musical Acoustics), or Fletcher &
Rossing (Acoustics of Musical Instruments), they are all available in
Gregg Bailey wrote:
> >The slightly less brief answer is that
> >for pipes that are closed at one end (the reed closes one end),
> Actually, the reed "closing" the end has absolutely nothing to do with it.
> If it did, then saxophones would be affected. Here's what I've gathered
> through all of my research throughout the years (even though I'm only 17),
> though I'll try not to get TOO detailed.....(there follows 4 pages of discussion, much of it "I don't know"....)
Date: Thu, 26 Aug 1999 09:24:21 -0700
From: Grant Green <firstname.lastname@example.org>
Subject: Re: Conical vs. cylindrical
>>The slightly less brief answer is that
>>for pipes that are closed at one end (the reed closes one end),
>Grant, I don't understand why you say that the reed stopping the end has
>anything to do with it, considering that conical resonators contradict it.
>Also, the reed only acts as a stopper at one infinitesimal point per cycle.
Nope: go back and read Benade (actually, I need to brush up too, but it
will have to wait until after this deadline...). The reed closing the pipe
is what explains the difference between flute and clarinet, which are both
cylindrical bore instruments. All flutes are "open" at both ends - the
embouchure hole is not sealed on a flute, whereas the player's mouth and
reed seal the end of reed instruments. On the organ, "stopped" pipes are
pipes that are closed at the *far* end: they're still open at the windway.
If both ends are open, the bore can be either cylindrical or conical
without affecting the octave that results. Note that recorders and some
piccolos are conical (actually reverse conical: they get narrower towards
the foot), whereas flutes and some other piccolos are cylindrical. It
affects the timbre, but not the pitch.
For stopped pipes (closed at one end), the bore profile affects the pitch.
Conical pipes play at the same octave as open pipes, whereas cylindrical
stopped pipes play an octave lower.
And now, back to work...
Grant Green email@example.com
Next Digest ->
Previous Digest <-