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 About ten years
ago I did alot of experimenting at the speech pathology
labof a local hospital. they let me use all kinds of amazing
equipment
(spectrometers,state of the art recording equipment, complex
computer
analysis programs on sound and aerodynamics etc...).
I had a bunch of my favorite local harmonica players come down
and blow
into various gadgets with the same and different harmonicas
much to their
amusement. The results were cataloged and analyzed and with
the help of two speech pathologists I came up with statistical
models to discuss tone production and the harmonica.
It was a lot of work, and at the end of it all I felt like
I knew less then
when I started. It did help me develop the ability to distinguish
between various timbres better, and gave me a vocabulary to
discuss it but... ultimately what I really wanted to do was
improve my own tone, and the research wasn't helping. I gave
up.
When it was all said and done I never finished the scientific
paper. I did write a small essay on what I learned for other
musicians. most of which was honestly pretty boring. i'd like
to include a mercifully abreviated version of that anyway, and
use it as a launching point for understanding and working on
Tone production.
the more important experiences i've had regarding tone have
been personal experiences as an enthusiastic listener, and player.
all of the time spent at the speech lab paled compared to one
day of actual street performing on a windy peer, or an evening
on stage trying to get more out of my amp & mic
technique, so as to be heard over the din of the local guitar
neanderthal.
Anyway, here it is-
TIMBRE
Timbre, is
how-you-tell-two-instruments-apart-that-are-playing-the-same-note-at-the-same-loudness.
It's the character that differentiates between tones with the
same frequency and volume.
Most of us know intuitively what timbre is. we've heard a difference
in our own sound as we switch from one harmonica to another.
we've also heard a difference between our "sound"
and another players sound playing the same harmonica. The first
time I really experienced the latter was during a lesson from
Eddie Manson. I thought my harmonica was having problems. he
took it from me a played one
long beautiful note, then a quick major scale and handed it
back to me. I couldn't believe it was my harp. I was demoralized,
but inspired.
Timbre is a complex topic. So "it is the character that
differentiates between two notes of the same frequency and amplitude"
great, but what does that mean. let's break it down a little.
There is a difference between amplitude and loudness. Amplitude
is a measure of sound pressure which is a quantity, a physical
attribute. Loudness is a quality, a perceptual attribute. loudness
is measured in
Bells. a tenth of a bell is a decibel. it takes three more decibels
to make the sound twice as loud, three less decibels and the
sound is half as loud.
The same is true with frequency and pitch. That is, frequency
is a quantity, a physical attribute, and pitch is a quality,
a perceptual attribute.
Furthermore, loudness differs with pitch. We hear middle frequencies
better than low and high ones of the same amplitude. "So
far there hasn't been any strong evolutionary pressure to hear
a really bithcin' bass groove. While middle frequencies 'Grok!
Run" saber tooth tiger ! Waga waga!", have been very
useful" -Dave Moulton (home recording magazine).
Let's simplify and discuss timbre only in relation to it's physical
attributes. All other things being equal two notes with different
timbre will have a different "spectra". One short
note on the harmonica is actually a complex tone made up of
many simple tones of various frequencies and amplitudes. These
simple tones are called "partials" or "harmonics"
(if they occur at regular intervals), they are called "noise"
(if they do
not). These can be viewed with a Spectrograph.
These two attributes of the timbre, it's SPECTRA and HARMONICS
TO NOISE RATIO, although important, are not the only attributes.
there is one other worthy of mention FORMANTS.
A formant is a boost, a hump in the spectra at a place that
has nothing to do with the fundemaental. a guitar has a large
formant made by its body. Some instruments have no formant,
an oboe for example. whether formants exist on the harmonica
remains to be seen.
For the purpose of brevity i'll limit the discussion to acoustic
tone. "Acoustic" tone is the sound just you and your
harp make before you step up to the Microphone. that is, prior
to it being processed by any transducer (a microphone or pickup)
and turned into an electronic signal. ELECTRIC tone is what
occurs after the transducer.
I think of acoustic tone as divided into three systems:
1) the vocal tract,
2) the harmonica,
-and-
3) the hands
(or coffee cup etc...) should you choose to use them (it).
Let's take a closer look at each of these.
The VOCAL TRACT is a 10 cm, flexible tube, capable of an infinite
number of subtle variations in shape an and volume. In speech
the noise generator (larynx) is located at the beginning of
the system, the back of your throat. The harmonica's noise generator
is at the opposite end of the system. With speaking, and singing
the formants are the throat and sinuses. Their size and shape
give your voice a different and often shifting timbre. With
harmonica the same is true but the role of formants is a much
less dramatic and less misunderstood.
The HARMONICA itself is a free reed instrument. It consists
of a comb, reed plates, reeds, cover plates, and if it's a chromatic,
it also has slide, cursed windsavers and a slide mechanism.
In the last few years there has been a lot of experimenting
and discussion here. It's lead to a great deal of clarification
and controversy. I'm certain that there is little can add to
the discussion that talented harmonica
customizers and bright mechanical engineers haven't already
covered. I recommend searching the Harp-l archives for the role
each part of the harmonica plays in timbre.
I have noticed that different harmonicas sound differently to
my ears when I play them. Also, I can say that they had different
spectra, and harmonics to noise ratios when I checked them out
with the spectrograph. whether that's the size of the reed plates,
or the material the cover plates are made of
etc... I honestly don't know. I just have my treasured opinions.
The HANDS play a huge role in shaping timbre. "They are
to the harp as stops are to the organ " according to my
mentor Eddie Manson. I believe they are undoubtedly the biggest
and most ignored tool in shaping the acoustic tone.
To get an idea of how exaggerated you can change the timbre
with this system (your hands) listen to the aforementioned Mr.
Mansons version of "The Polka" by Shostokovich (the
little fugitive suite -Folkways), or for subtlety, listen to
"Joey's Theme" on the same LP. For that matter listen
to anything by Tom Ball. each solo is a lesson in depth and
blues history.
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