Klarinet Archive - Posting 000276.txt from 1996/09
From: Jonathan Cohler <cohler@-----.NET>
Subj: The Real Deal on Clarinet Tone ("Dark",
Date: Sat, 14 Sep 1996 23:37:10 -0400
There has been so much discussion of this lately that I can't resist
jumping in and stirring things up with a bit of physical reality.
Clearly, there are many misconceptions floating about.
With this brief discussion, I hope to clarify some of the major issues:
1) Does a clarinet have a tone?
2) If so, what is THE major physical variable that determines
clarinet tone (or woodwind instrument tone in general)?
3) Is there a meaningful, physical, and objective definition of
the terms "darker" or "brighter" as applied to woodwind
instrument tone?
4) Has anybody experimentally tested and verified all this stuff?
First, as we all know as clarinetists, there are many variables that effect
tone quality: mouthpiece, reed, embouchure, mouth/tongue position, air
pressure, and of course the clarinet itself. At an extreme, if a clarinet
is built poorly, with bad spacing and sizing of holes, not only will notes
be out of tune (which has nothing to do with tone quality), but some notes
will be noticably "fuzzy" or "stuffy" (i.e. not very resonant). If a reed
is bad (too hard, too soft, out of balance), nobody can make it sound great
throughout the range of the instrument.
Furthermore, different players produce different sounds on the same
clarinet, because they use different mouthpieces, reeds, mouth/tongue
positions, and blowing pressures.
All of that aside, for my discussions here, I am assuming professional
level players that have "good" mouthpieces, reeds, embouchures, clarinets,
etc... Another part of the "professional player" assumption is that they
can produce consistent results on a given mouthpiece/reed/instrument
combination.
Now here's another way of looking at question 1 above. If a group of
professional players play clarinet A and clarinet B, and the vast majority
of them agree that one is "brighter" and one is "darker", then there should
be a measurable physical quantity (or quantities) that correlates with this
professional opinion.
The fact is that **there is such a physical quantity**, **this experiment
has been done** and **the physical quantity is in precise agreement with
the players opinions**.
Here's where it gets a bit technical, so I'll try to keep it brief. The
quantity is called the "cutoff frequency". A clarinet is basically a
cylindrical tube, closed at one end, with a tone-hole lattice. As one
opens and closes holes with the fingers, the tone-hole lattice changes.
Each tone hole lattice (for each fingering) has a characteristic "cutoff
frequency" which can be calculated given the size, shape and spacing of the
holes, as well as the size, shape and length of the bore.
You've probably always heard that opening the holes on a clarinet is
equivalent to shortening the length of the tube. That's partially true.
The cutoff frequency is the frequency above which sound waves will continue
to propagate down the tube (and out holes further down). Waves at
frequencies less than the cutoff are reflected back up the tube.
So what's the practical effect of this? As you know, each note on the
clarinet is comprised of a set of harmonics. Because of the closed-end
nature of the clarinet, the harmonics are odd multiples of the fundamental
frequency. Consider a low B (220hz - concert A). Its harmonics would be
at 660Hz, 1100Hz, 1540Hz, 1980Hz, etc... But if you look at the resonance
curve of a typical Buffet clarinet you'll find that there are clearly
defined peaks of decreasing amplitude at 660, 1100 and 1540, but above that
the peaks go away. That's because the cutoff-frequency of the Buffet on a
low B is around 1600Hz.
In other words, the cutoff frequency for a given fingering determines how
many of harmonics will be well defined and of substantial amplitude in the
spectrum of the note.
Arthur Benade did substantial experimentation and measurement of clarinets,
oboes and bassoons and discovered the following amazing (and amazingly
simple) facts about these instruments. This is quoted from his book.
1. On most of the standard woodwinds, the cutoff frequency remains
roughly the same as tone holes are progressively opened to finger
the notes of the low-register scale.
2. It proves possible to correlate the tone-color adjectives used by
musicians to describe the overall tone of an instrument (dark or
bright, for instance) with the value of its average cutoff frequency.
3. Trends in the cutoff frequency on a given instrument run parallel
to trends in the described tone color; furthermore, anomalies of
certain notes on a given instrument can be related directly to
local anomalies in the cutoff frequency.
In practice, this means that because of the precise physical specifications
that clarinets are manufactured to these days the cutoff frequency curve
for two R13 Buffets made according to the same specs would be virtually
identical. A professional listener would, in most cases, not be able to
reliably distinguish between these two instruments (played by a single
professional using the same setup on both), unless there was some
manufacturing defect in one that made a particular note out of tune or
drastically changed the cutoff on a note or group of notes.
On the other hand, the cutoff curve for an R13 A clarinet is substantially
below that of and an R13 Bb clarinet, and correspondingly professional
listeners CAN reliably (in blind studies) tell the difference, and will
note that the A clarinet is "darker".
Furthermore, clarinets from different makers and periods have markedly
different cutoff curves, and are consequently quite distinguishable. By
the way, remember that the fingering system itself does not determine the
cutoff frequencies, but rather the size and placement of holes does.
Therefore, to say just because a clarinet has a German system (Oehler or
Mueller or other) means that it is darker is erroneous. There are in fact
German system clarinets that are brighter and others that are darker than
the standard Buffet R13.
For further reading on this subject and much more detail, references,
graphs and equations, check out my favorite book on the subject,
"Fundamentals of Musical Acoustics," Second, Revised Edition by Arthur H.
Benade, Dover Publications, Inc., New York, NY, 1990.
----------------------
Jonathan Cohler
cohler@-----.net
P.S. For those interested in practical applications of all this: My Rossi
clarinet is definitely "darker" than my R13 (i.e. it has a lower average
cutoff frequency), as well as being better in a hundred other ways!
