Klarinet Archive - Posting 000964.txt from 1998/11

From: Tony@-----.uk (Tony Pay)
Subj: Re: [kl] Why I can't play in tune: a clarinetist's apology
Date: Wed, 25 Nov 1998 11:56:01 -0500

On Wed, 25 Nov 1998 03:30:39 -0600 (CST), pergler@-----.edu said:

> As an enthusiastic amateur, I've heard a lot of good advice about
> intonation, some useless advice too, but little systematic info
> about where the problems come from. So I took a stab at writing a
> short article on what (in my albeit limited experience) causes
> intonation problems and what we as players can learn to do better. I
> would much appreciate any feedback or commentary. It's at
> http://www.math.uchicago.edu/~pergler/tuning.html

Just skimming through, there's a wrinkle you might want to add, though
given the difficulty I just had writing it down, perhaps not:-) But as
a physicist, you might do better.

The sound of a wind instrument like the clarinet, which is a driven
oscillation, is different in character from the sound of a piano, harp
or percussion instrument, which is an oscillation that is set in motion
initially by the player and then decays by itself. Piano manufacturers
are at pains to minimise this difference by careful design, but you can
hear an extreme example of the sort of problem the difference creates if
you try playing in tune with the sound of a bell, which is not designed
to minimise the difference.

The effect of the difference shows up in our perception of pitch,
because the perceived pitch of any sound does not simply depend upon its
fundamental frequency of oscillation. It also depends on the other
frequencies that are 'present' in the sound. This is a fact of
psychoacoustics, by the way, not a fact of acoustics itself.

The sound of a bell contains higher frequencies that are not whole
number multiples of the lowest, because the bell, due to its shape, has
a number of independent modes of vibration that are all present just
after it is struck, and persist independently. Nevertheless, our ear
and brain 'try' to hear the bell as one pitch plus a timbre rather than
a straight chord, and that one pitch is assigned by our hearing
mechanism on the basis both of the lowest frequency and on the results
of an attempt to fit the remaining 'rogue' partials into the framework
of a harmonic series of a lower frequency -- a sort of 'implied'

Then, roughly speaking, we hear the bell at a pitch that corresponds to
a frequency midway between the lowest frequency present in the sound and
the frequency of that 'implied' fundamental.

The 'driven' sound of a wind instrument, on the other hand, settles into
a steady state in which the first few upper partials *are* in a whole
number, harmonic series relationship with the fundamental, so in this
case the fundamental implied by the upper partials coincides with the
real fundamental.

The upshot is that the pitch that a clarinet needs to be at to sound
'the same note' *following* a note on a piano, harp, or (worst case
scenario) bell, may be different from the pitch it needs to be at to
achieve 'zero beats' when it plays *together* with a note on a piano,
harp or bell. Worse, when the two instruments play together, they can
sound out of tune, but changing the pitch of the clarinet doesn't help.

Ain't that strange?

String instruments are an intermediate case, because the bow mechanism
doesn't constrain the vibrations of the string to harmonicity to quite
the same extent as the blowing mechanism on wind instruments. This
also means that string instruments can tolerate more out-of-tuneness
before sounding terrible than wind instruments.

Another thing you might want to mention is the degree to which an
assessment of whether something is in tune or out of tune is learned.
If I listen carefully to a piano, I find I can become aware both that it
*is* out of tune, and that I accept it *as in tune*. This is even
clearer in the case of the organ -- listen to the beginning of a simple
passage of harmony on an equal-tempered organ, and then imagine as you
listen that it's being played by the New York Philharmonic wind section.
Shock, horror, wince!

One more: I know this is controversial, but I'm satisfied myself: the
glissando is less to do with embouchure than with mouth shape, ie tongue
position. (This probably needs a separate post.)

I thought your article was very good and informative, and a contribution
to understanding these matters.

_________ Tony Pay
|ony:-) 79 Southmoor Rd Tony@-----.uk
| |ay Oxford OX2 6RE
tel/fax 01865 553339

"...his playing soars so freely, one is aware of witchcraft without
noticing a single magical gesture."
(C.D.F.Schubart on the harpsichord playing of C.P.E.Bach)


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